Nanostructured MoS2-Based Advanced Biosensors - American ...

This article is made available for a limited time sponsored by ACS under the ACS Free to Read License, which permits copying and redistribution of the article for non-commercial scholarly purposes.

Review Cite This: ACS Appl. Nano Mater. 2018, 1, 2−25

www.acsanm.org

Nanostructured MoS2‑Based Advanced Biosensors: A Review Shaswat Barua,†,‡ Hemant Sankar Dutta,† Satyabrat Gogoi,† Rashmita Devi,† and Raju Khan*,† †

Analytical Chemistry Group, Chemical Sciences & Technology Division, Academy of Scientific and Innovative Research, CSIR-North East Institute of Science & Technology, Jorhat 785006, Assam, India ‡ Department of Chemistry, School of Basic Sciences, Assam Kaziranga University, Koraikhowa, NH-7, Jorhat 785006, Assam, India ABSTRACT: The introduction of nanotechnology in biosensor applications has significantly contributed to human lifestyle by rendering advanced personalized diagnostics and health care and monitoring equipment and techniques. Nanomaterials and nanostructures have recently gained impetus in the domain of biosensors because of their manifold applications. Transition-metal dichalcogenides (TMDs) newly attracted interest because of their multidimensional structures and structure-dependent unique electronic, electrocatalytic, and optical properties, which can be explored to design novel biosensing platforms. The content of the present article aspires to advocate a critical evaluation on the recent advances in the domain of dimensionally different MoS2, the most widely explored TMD, and their relevance in biosensing application. This encompasses the major structural attributes and synthetic methodologies of zero-, one-, two-, and threedimensional MoS2 nanostructures, pertaining to their biosensing potential. Herein, we described the prevailing and potential applications of MoS2 nanostructures in optical, electrochemical, and electronic biosensors. KEYWORDS: MoS2, advanced biosensor, nanostructures, optical, electrochemical

1. INTRODUCTION

In broader aspects, nanomaterials can be categorized as zero(0D), one- (1D), two- (2D), and three-dimensional (3D) structures. The synthesis and applications of MoS2 with different dimensions have been well documented in the literature. Variation of the precursors, synthetic materials, and methodologies mainly dictates the shape and size of the MoS2 nanostructures.10−12 Each dimension has a unique attribute that renders tremendous potential for biosensing applications. 0D MoS2 quantum dots, also referred to as “inorganic fullerenes”, are nanooctahedral structures with size 100 nm. 3D nanomaterials include nanoclusters, nanodispersions, etc. Recent literature showcased the synthesis of 3D hierarchical architectures based on the selfassembly of MoS2. Such assembled nanomaterials have shown immense potential as hydrogen evolution reactors, visible-light photocatalysts, high-performance flexible supercapacitors, lithium-ion batteries, etc.91−93 However, very few reports have endorsed the biosensing capabilities of 3D MoS2. 2.4.1. Structure of 3D MoS2. Efficient 3D MoS2 nanostructures, like nanoporous sheets, core−shell, double-gyroid, vertical nanoflakes, etc., have been studied by a few research groups.95−99 Kong et al. described the 3D structure of MoS2 in comparison with MoSe2.97 One neutral layer was described to consist of three covalently bonded sheets of atomic thickness, with an interlayer distance of 6 Å (Figure 17). Such crystals have two kinds of sites, viz., terrace and edge. Anisotropic bonding and surface energy prefer platelet-like morphology for such layered nanomaterials.85,97,100,101 Figure 17d shows the TEM and HRTEM images (showing atomic planes) of the densely packed grain-like morphology of MoS2 with an individual grain size of about 10 nm. Raman spectra for 3D MoS2 nanostructures are shown in Figure 17e. Again, Figure 17f represents the excited A1g and E12g modes for the edge- and terrace-terminated MoS2 respectively, while Figure 17g shows the Raman spectrum for the terrace-terminated MoS2.85 Again, Lu et al. observed a nanoflower-like morphology (Figure 18) of 3D MoS2 nanostructures, with larger stretched “thin folding leaves”, when observed under SEM and TEM. Further, HRTEM images revealed the (002) plane of MoS2 with an interlayer spacing of ∼0.65 nm.95 2.4.2. Synthesis of 3D MoS2. 3D MoS2 and MoSe2 thin films were synthesized by Kong and co-workers in 2013, with vertically aligned layers.85 They demonstrated that the sulfurization reaction undergoes diffusion of sulfur into the MoS2 layers and converts it into sulfide. Again, 3D MoS2 sheets were synthesized by using tetrakis(diethylaminodithiocarbo-

Figure 13. (a) STEM−HAADF image of 2D MoS2. (b and c) Filtered images of MoS2 layers, distinguishing molybdenum and sulfur. Reprinted with permission from ref 80. Copyright 2013 Nature Publishing Group.

results in interesting excitonic and fluorescent attributes that have immense utility in biosensing. 2.3.2. Synthesis of 2D MoS2. The most common method for synthesizing 2D MoS2 nanosheets includes the exfoliation of layers from bulk MoS2 by ultrasonication.83 Mechanical or ultrasonic exfoliation generally results in uniform monolayers, which, however, suffer some demerits like low yield, flake deposition, etc. Solution-based exfoliation techniques are used to obtain mixtures of single-layer and multilayered MoS2 sheets. Organic solvents, metal-ion intercalation, and the use of surfactants facilitate such exfoliation processes.84−89 Surfactant-free liquid-exfoliation methods were also reported, which led to the production of 2D-layered MoS2.85 Different solvent systems were investigated for the efficient dispersion of MoS2 sheets, although low-boiling ones are preferred for the subsequent drying process.90 Again, chemical gas or vapor deposition techniques have been employed to synthesize 2D MoS2 nanosheets. Liu et al. recently synthesized 2D MoS2 thin layers by a two-step thermolysis process, taking (NH4)2MoS4 as the precursor (Figure 15).89 The high-temperature-annealed ammonium thiomolybdate produced MoS2 layers with high surface area, which resulted in augmentation of the electrical properties. However, large-area uniformity with controllable synthesis is still a challenge. Chemical vapor deposition techniques are useful in synthesizing a wafer-scale 2D MoS2 with a wide potential for electronic applications. Lin et al. reported a waferscale synthesis of MoS2 layers by a two-step thermal process, using MoO3 as the precursor in the presence of sulfur (Figure 16).8 The chemical equations involved in this process are MoO3(s) + H 2(g) → MoO2 (s) + H 2O(g)

(3)

(2)

Figure 14. (a) FESEM image of MoS2 nanosheets. (b) TEM image showing lateral dimensions and (c) electron diffraction pattern of 2D MoS2. Reprinted with permission from ref 81. Copyright 2015 Nature Publishing Group. 8

DOI: 10.1021/acsanm.7b00157 ACS Appl. Nano Mater. 2018, 1, 2−25

Review

ACS Applied Nano Materials

Figure 15. Two-step thermolysis process for synthesizing 2D MoS2. Reprinted with permission from ref 89. Copyright 2012 American Chemical Society.

Figure 16. (a) Schematic illustration for the synthesis of MoS2 layers by MoO3 sulfurization. (b) MoS2 layer grown on a wafer. Reprinted with permission from ref 30. Copyright 2012 Royal Society of Chemistry.

Figure 17. (a) Layered crystal structure of S−Mo−S (or Se−Mo−Se). (b) Platelet-like nanostructures and nanotubes of MoS2 and MoSe2. (c) 3D nanostructures of MoS2. (d) TEM image of 3D MoS2 (the HRTEM image shows three atomic planes of S−Mo−S). (e) Raman spectrum from MoS2. (f) Excited A1g and E12g modes, respectively, for edge- and terrace-terminated MoS2. (g) Raman spectrum for terrace-terminated MoS2. Reprinted with permission from ref 97. Copyright 2013 American Chemical Society.

19a).91 Parts b−d of Figure 19 show 4 and 15 layers of graphene and the selected-area electron diffraction (SAED) pattern, respectively. A schematic diagram of the experimental setup and the optical images of the samples are shown in Figure 19e,f. Further, in 2014, the self-assembly of MoS2 nanostructures with 3D hierarchical frameworks was performed by a

mato)molybdate(IV) as the precursor of both molybdenum and sulfur. The synthesis was comprised of a chemical vapor deposition method, where graphene was first synthesized onto a 3D nickel foam. Subsequently, it was reacted with tetrakis(diethylaminodithiocarbomato)molybdate(IV) to obtain 3D MoS2/graphene/nickel (3D MoS2/G/Ni;Figure 9


Review


Figure 18. (a) SEM and (b) TEM images showing the nanoflower-like morphology of 3D MoS2. (c) HRTEM image showing the interplanar distance with the (002) plane. Reprinted with permission from ref 95. Copyright 2017 Nature Publishing Group.

Figure 19. (a−c) Schematic depiction of 3D MoS2/G/Ni nanostructures. (b and c) HRTEM image of graphene. (d) SAED pattern. (e) Experimental setup for the synthesis. (f) Optical images of the samples. Reprinted with permission from ref 91. Copyright 2014 Wiley-VCH Verlag GmbH & Co. KGaA.

simple hydrothermal method.102 Such methods have also been employed for synthesizing MoS2 nanoflowers on a carbon fiber cloth. These nanosheet-assembled MoS2 nanoflowers were synthesized by using Na2MoO4 and CSN2H4 as precursors (Figure 20). Then GO was added to recover the rapid capacity fading of the MoS2 nanoflower-based anode.94 Further, MoS2-coated carbon foam/nitrogen-doped graphene were successfully synthesized by using 3D melamine foams. Very recently, Zhang et al. reported the successful synthesis of a visible-light-responsive self-assembled MoS2/ RGO by a hydrothermal method.92 Subsequent freeze-drying yielded a 3D aerogel, which showed potential as a visible-light photocatalyst.

It has been observed that a hydrothermal approach is the most widely used method for synthesizing nanostructured MoS2, regardless of the dimensions. However, literature reports on 3D MoS2 are very few to date.

3. PROPERTIES 3.1. Electronic Properties. Band structure and density of states dependent electronic properties of a MoS2 monolayer are inevitable in determining its application in electronic devices. The band structures of MoS2 have been calculated by Kuc et al. using the first-principle calculations with Perdew−Burke− Ernzerhof (PBE) exchange-correlation functionals. The incorporation of the PBE scheme in DFT to obtain the band 10


Review


bulk with a fundamental band gap of ∼1.2 eV, which initiates because of the transition from the Γ high-symmetry point of the valence-band maximum to the conduction-band minimum present between the Γ−K high-symmetry points, as shown in Figure 21. However, the position of the conduction-band minimum at the Γ point is dependent on the interlayer interactions.104,105 Therefore, by a reduction of the number of layers from the bulk form, the conduction-band minimum shifts to a higher energy at the Γ point of the Brilluoin zone. Nevertheless, the band-energy values at the K point stay almost unchanged with a change in the slab thickness. This opens up the direct-band-gap behavior at the K point in the monolayer structure with an energy difference of ∼1.9 eV.103,106 However, it has been proposed that reducing the number of layers increases the exciton binding energies from 0.1 eV (in the bulk system) to about 1.1 eV (in the monolayer) because of the strongly reduced dielectric constants.107 The excitonic effects should be incorporated in order to calculate the fundamental band gap. The GW approach, where the self energy is given by

Figure 20. Synthesis of RGO-decorated MoS2 nanoflowers. Reprinted with permission from ref 94. Copyright 2015 American Chemical Society.

structures increased the fraction of accuracy with the experimental results.103 MoS2 is an indirect semiconductor in

Figure 21. (a) MoS2 band structure calculated at the DFT/PBE level with a reduction in the number of layers from the bulk to the monolayer. The red dashed line shows the Fermi level, and the colored lines (blue and green) indicate the energy bands (valence and conduction) of the structure. The arrows indicate the fundamental band gap for the given system. Reprinted with permission from ref 103. Copyright 2011 American Physical Society. (b) Brillouin zone and high-symmetry points of the MoS2 reciprocal lattice. 11


Review


Figure 22. (a) (i) PEG-MoS2 captured by bacteria. (ii) Catalytic decomposition of H2O2. (iii) Laser irradiation (808 nm) inducing hyperthermia and accelerating GSH oxidation. (b) Bacterial colonies of E. coli incubated in (I) phosphate-buffered saline (PBS), (II) MoS2, (III) H2O2, (IV) MoS2 + H2O2, (V) PBS + NIR, (VI) MoS2 + NIR, (VII) H2O2 + NIR, and (VIII) MoS2 + H2O2 + NIR. Reprinted with permission from ref 130. Copyright 2016 American Physical Society.

mobility.115 Nevertheless, at sufficiently scaled lengths, such issues may not be significant because the performance would mainly depend on the contacts rather than transport through the channel.116 3.2. Catalytic Properties. Recently significant works have been reported showing the catalytic activity of MoS 2 nanostructures and MoS2-based heterostructures.117−128 Edges and metallic 1T polymorphic MoS2 nanostructures provided the catalytic activity. The catalytic activity is further dictated by nanostructures with atomic-level precision.129 Recently, Yin et al. reported a poly(ethylene glycol)-functionalized MoS2 nanoflower (PEG-MoS2 NF) system that showed profound catalytic effects during the decomposition of H2O2, generating a hydroxyl radical.130 This system induced a near-IR (NIR) photothermal effect, which imparted an excellent antibacterial effect against both Gram-positive and Gram-negative bacteria. GSH oxidation was observed to be accelerated by NIR irradiation with effective bactericidal activity by inducing hyperthermia (Figure 22). Further, the edges of MoS2 mediate proton adsorption and, subsequently, dihydrogen formation. The electrical conductivity and redox electrochemistry of MoS2 endorses them for energyconversion- and storage-device-based applications.131 Yu et al. observed the electrocatalytic activity for hydrogen evolution by forming Ni−Co−MoS2 nanoboxes.131 Interestingly, it was reported that the catalytic activity of MoS2 for such a reaction decreases with increasing layers.130 Moreover, MoS2 nanostructures have also been investigated for their electrocatalytic activity in solar cells.132

the product of the Green’s (G) function and the screened Coulomb interaction (W), has been used to calculate the fundamental band gap of the MoS2 monolayer and is found to be ∼2.8 eV.108 The band-gap property of the MoS2 monolayer makes it a promising candidate for nanoelectronic biosensing applications. It has higher potential than its analogue graphene in such applications, which lacks the band-gap property in its original form. Demonstration of the MoS2 monolayer with room temperature on/off ratios of 1 × 108, mobility of >200 cm2 V−1 s−1, and ultralow standby power dissipation has enabled the realization of practical electronic devices.109−111 Moreover, the MoS2 monolayer has a carrier lifetime of ∼100 ps and a diffusion coefficient of ∼20 cm2 s−1.112 Conclusively, it is worth mentioning that the above properties are highly suitable to establish field-effect and electrochemical-based biosensors. The precision in fabricating MoS2 down to a monolayer configuration with uniform thickness control enables accurate control of the electrostatic characteristics of the transistor. The lower in-plane dielectric constant is also attributed to precise control of the electrostatic characteristics, thereby pushing its limit to sub-5-nm-scale transistor technology.113,114 Notably, electron transport in the MoS2 monolayer is much slower compared to that in bulk semiconductors. Yu et al. listed approaches for improving carrier transport in the MoS2 monolayer and accounted for intrinsic electron−phonon scattering, surface optical phonon scattering, Coulombic impurity scattering, atomic defect scattering, charge trapping, and metal-to-insulator transitioning as the reasons for low 12


Review


Figure 23. (a) Differential-reflectance spectrum showing A and B exciton absorption. The red, yellow, and green arrows represent the different exciting photon energies and (b) PL spectrum for 2.33 eV (532 nm) excitation showing A and B exciton luminescence. Reprinted with permission from ref 137. Copyright 2012 Nature Publishing Group. (c and d) Layer-dependent PL and Raman spectra showing the dramatic increase of the luminescence quantum efficiency in the MoS2 monolayer. Reprinted with permission from ref 138. Copyright 2010 American Chemical Society. (e) Peak position of the Raman modes and their dependency on the layer thickness. Reprinted with permission from ref 139. Copyright 2012 WileyVCH Verlag GmbH & Co. KGaA. (f) Refractive index and extinction coefficient variation of the monolayer with the wavelength. Reprinted with permission from ref 140. Copyright 2014 AIP Publishing LLC.

Figure 24. (a) Fabrication of a gold/MoS2 electrode: (1) molybdenum deposited on a gold electrode using an e-beam evaporator, (2) H2S + Ar plasma reacting with a molybdenum film in a PECVD chamber, (3) H2S penetrating into molybdenum, and (4) a MoS2 biosensor device. Reprinted with permission from ref 153. Copyright 2015 Royal Society of Chemistry. (b) Construction of a TMD biosensor electrode by drop-casting on a GC electrode, followed by immobilization of GOx, cross-linked with glutaraldehyde (GTA) for the electrochemical sensing of gluocose. Reprinted with permission from ref 147. Copyright 2017 American Chemical Society. (c) Biofunctionalization layers on a MoS2 device surface. Reprinted with permission from ref 151. Copyright 2014 John Wiley and Sons. (d) MoS2-based modified electrodes for glucose sensing (S, source; D, drain). Reprinted with permission from ref 152. Copyright 2015 John Wiley and Sons.

3.3. Optical Properties. The layer-dependent bandstructure variation in MoS2 is of particular interest among researchers for its optoelectronic properties. The generation of

a direct band gap in monolayer MoS2 provides strong luminescence properties, which are absent in the bulk material. In addition to the changes in the band structure, there is a 13


Review


Figure 25. (a) Voltametric detection of H2O2 by a MoS2/GOx-modified electrode and (b) amperometric responses of a MoS2-modified electrode. Reprinted with permission from ref 154. Copyright 2013 American Chemical Society. (C) SWV responses of the modified electrode in 0.1 M PBS with injections of dsDNA. Reprinted with permission from ref 155. Copyright 2014 American Chemical Society. (d) EIS response (Nyquist plots) of thrombin and adenosine triphosphate (ATP) detection by usinga gold/MoS2-based biosensor. Reprinted with permission from ref 156. Copyright 2016 American Chemical Society.

intensity. A slight red shift in the absorption resonance and PL energy was observed with increasing film thickness.141 The minor shift can be ascertained by the fact that the direct band gap is only slightly sensitive at the K point to the layer thickness because of the quantum confinement effect.142 The possession of PL characteristics provides the possibility of using such structures in fluorescence-based applications, which can be used to trace, image, and sense biological components.143,144 The Raman characteristics of the MoS2 monolayer is also a function of the dimension and permittivity of the environment. Attaching biological components may alter such characteristics and thus can be used as a biosensing principle.145,146

structural change in the thin-film MoS2. The inversion symmetry existing in the bulk and thin films with an even number of layers is explicitly broken in films with odd numbers of layers. This leads to the generation of a valley-contrasting optical selection rule, thus allowing spin-valley-coupled band structures.133 The broken inversion symmetry breaks down Kramers’ degeneracy and splits the valence bands by ∼160 meV.134 This leads to the possession of strongly bound excitons whose binding energies depend on the number of layers. These excitons decide the optical properties of the material, as shown in Figure 23. The optical absorption spectrum is obtained by measuring the differential reflectance of MoS2 samples on a substrate and the bare substrate of hexagonal boron nitride. The pronounced absorption minima correspond to the A and B excitons (Figure 23a).135,136 Figure 23b shows the PL spectra for the total unpolarized emission under 2.33 eV (532 nm) excitation. The strongest emission near 1.9 eV (652 nm) arises from A exciton complexes, the weaker emission at 2.1 eV (590 nm) is due to the B excitons, and the feature near 1.8 eV (688 nm) corresponds to emissions from defect-trapped excitons.137 Again, Splendiani et al. demonstrated the layer dependence of the PL and Raman signals in MoS2.138 With a increase in the number of layers from the monolayer, the PL signal decreased; however, the Raman signal slightly improved because of the increased amount of material interaction. Nevertheless, the intrinsic quantum efficiency increased dramatically on going toward the monolayer structure because there is a huge jump in the PL emission.139,140 The weak interlayer coupling between the restacked MoS2 sheets gradually decreased the emission

4. APPLICATION OF MOS2 IN BIOSENSING 4.1. Electrochemical Biosensors. Recent development in electrochemical biosensors mostly focuses on the use of nanomaterials and nanostructures. TMDs have attained significant attention of the scientific community because of their analogous attributes to that of graphene. In a recent report, Rohaizad et al. demonstrated the fabrication of an electrochemical biosensor by exfoliation of TMD for efficient sensing of glucose up to 2.8 μM.147 The construction of such biosensors includes the selection of the matrix material, fabrication of the electrode, use of a mediator (or mediator free) for immobilization of the labeling biomolecules (or label free), and detection of analytes using electrochemical techniques.144 Glassy carbon (GC), platinum, indium−tin oxide, and screen-printed electrodes are generally used for anchoring the biosensor matrix by different techniques like 14


Review

ACS Applied Nano Materials Table 1. List of Analytes, LODs, and Techniques Used in the Fabrication of MoS2-Based Electrochemical Biosensors serial no.

matrix

analyte

technique

LOD

ref

1 2 3 4 5 6 7 8 9 10 11 12 13 14

MoS2 MoS2 MoS2 nanoparticles MoS2/thionine MoS2/poly(xanthurenic acid) MoS2/PANI gold/MoS2 MoS2 single layer gold/MoS2 nanoparticles gold/MoS2 MoS2/PANI poly(m-aminobenzenesulfonic acid)-reduced MoS2 nickel-doped MoS2/RGO MoS2

glucose H2O2 H2O2 dsDNA adenine and guanine chloramphenicol miR-21 dopamie thrombin and ATP ribaflavin adenine and guanine dopamine glucose glucose

CV CV amperometry SWV DPV DPV DPV CV CV DPV DPV DPV CV CV

2.8 μM 20 ng mL−1 2.5 μM 0.09 ng mL−1 3 × 10−8 for adenine, 1.7 × 10−8 for guanine 6.9 × 10−8 mol L−1 0.26 pM

147 153 154 155 165 166 167 171 172 173 174 175 176 177

0.74 nm for ATP, 0.0012 nM for thrombin 20 nM 3 × 10−9 for adenine, 5 × 10−9 for guanine 0.22 μM 0.042 μM

Figure 26. MoS2-based FET biosensor. (a) Schematic diagram of the sensing scheme showing the MoS2 channel functionalized with receptors for specifically capturing the target biomolecules and the drain and source contacts and the Ag/AgCl reference electrode for biasing the device, (b) optical image of a MoS2 flake in a SiO2/silicon substrate (scale bar = 10 μm), (c) optical image of the FET device, (d) image and schematic (inset) showing the macrofluidic integrated FET chip, (e) transfer characteristics of a biotin-functionalized FET device measured in a pure buffer (0.01× PBS), with the addition of a streptavidin solution (10 μM in 0.01× PBS) and again with a pure buffer, and (f) comparison of the sensitivities in the subthreshold, saturation, and linear regions of the transistor device. Reprinted with permission from ref 184. Copyright 2014 American Chemical Society. (g) Image of the FET biosensor integrated with a PDMS (polydimethylsiloxane) reservoir and (h) experimental setup showing an inlet/ outlet tubing kit, driven by a motorized syringe pump. Reprinted with permission from ref 183. Copyright 2015 Nature Publishing Group.

15


Review

ACS Applied Nano Materials drop-casting, electrochemical deposition, etc.148−150 Further, HfO2, silicon wafer, etc., are used for device fabrication.151,152 Kim et al. recently demonstrated an in situ synthesis of MoS2, on a polymeric printed circuit board, using a plasma-enhanced chemical vapor deposition (PECVD) technique for efficient sensing of H2O2.153 Figure 24 shows different types of MoS2based electrochemical biosensors for the sensitive detection of bioanalytes. Most of the electrochemical biosensors based on MoS2 nanostructures employ potentiometric and amperometric techniques for the detection of bioanalytes. Besides, squarewave voltammetry (SWV), differential-pulse voltammetry (DPV), and electron impedance spectroscopy (EIS) are the commonly used techniques for detecting bioanalytes with a high level of sensitivity.154−156 Figure 25 shows the widely used techniques for MoS2-based electrochemical biosensors. A range of analytes have been successfully detected by MoS2based electrochemical biosensors. MoS2-based hybrid materials have also been explored for the fabrication of sensor probes for the highly selective and sensitive detection of bioanalytes.157−164 Poly(xanthurenic acid) based on MoS2 support was electrochemically synthesized by Yang and co-workers. They prepared a highly electroactive biosensing matrix by an ultrasonic method for the efficient detection of guanine and adenine.165 With a similar approach, a MoS2 and PANI composite was prepared through the in situ electrochemical detection of chloramphenicol.166 Again, gold nanoparticle decorated 2D MoS2 nanosheets were used for the electrochemical sensing of glucose in the presence of commonly interfering species like ascorbic acid, dopamine, uric acid, and acetaminophen.21,167 A myoglobin-immobilized 0D MoS2 nanoparticles−GO hybrid was fabricated by Yoon and coworkers for the detection of H2O2. They observed the enhancement of the electrochemical signal because of GO, which may be attributed to the high surface area available for the immobilization of myoglobin.168 With a similar approach, an extremely sensitive (2.5 nM) H2O2 biosensor based on MoS2 quantum dots (∼2 nm) was fabricated by Wang et al. in 2013.152 Another thionin-functionalized MoS2-based electrochemical biosenser was fabricated for the direct detection of DNA with sensitivity up to the ppb level.153 Electrochemically reduced single-layer 2D MoS2 nanostructures exhibited a fast electron-transfer rate, which helped in the detection of glucose with high sensitivity.169 Micromolar-level electrochemical biosensing of glucose was achieved by using a glucose oxidase (GOx)-immobilized gold/MoS2 nanohybrid.170 Literature reports primarily showcased the utility of 2D MoS 2 nanostructures in the development of electrochemical biosensors.163 However, MoS2 nanostructures of other dimensions have also been explored for the biosensing of different analytes, which will be discussed in the following sections. Table 1 encompasses a list of analytes, lowest detection limits (LODs), and techniques used in the fabrication of MoS2-based electrochemical biosensors. 4.2. Field-Effect Transistor (FET)-Based Biosensors. FET-based biosensors are of great interest for researchers for its highly desirable characteristics of label-free rapid electrical detection capabilities, low power consumption, mass production, compactness, and the possibility of on-chip integration of the chip with measurement systems. FET conventionally consists of two electrodes (drain and source) that are connected electrically via a semiconductor material (channel). The current flow between the drain and source through the

channel is modulated by a third electrode, namely, a gate, which is capacitively coupled through a dielectric layer covering the channel. Capturing biomolecules using a functionalized channel produces an electrostatic effect that is transduced into a readable signal in the form of a change in the electrical characteristics of the FET device.178 Nevertheless, the performance characteristics are dependent on the biasing strategy of the device.179 Figure 26 illustrates the sensing principle, detection strategy, and chip design of MoS2-based FET biosensors. The possession of a direct band gap in MoS2 allows better control between the conductive and insulated states and also prevents leakage currents.180 This permits the designed FET to obtain higher sensitivity and accurate sensing with a very low concentration of the analytes. However, in comparison to its counterpart, a graphene-based FET device possesses a zero band gap and thus cannot be switched off, thereby inducing leakages and a higher potential for inaccuracies.181 Furthermore, the absence of out-of-plane dangling bonds in MoS2 reduces the surface roughness scattering and interface traps. This results in better electrostatic control due to the lower density of the interface states on the semiconductor−dielectric interface, thereby reducing the low frequency noise, which hinders the performance of FET-based biosensors.182 MoS2-nanosheet-based FET biosensors have been demonstrated to detect proteins, pH, cancer biomarkers, etc., with high sensitivity and selectivity.183−186 It has been articulated that a few-layer MoS2-film-based FET device shows a more stable and sensitive response than the monolayer-based device.139 Chip integration with microfluidics opens up huge prospects in realizing compact sensor systems with clinically meaningful detection limits, allowing their usage in point-ofcare diagnosis applications.187,188 Additionally, recent developments in the synthesis and growth of MoS2 thin films as well as a demonstration of the integrated logic circuits on MoS2 illustrate the viability of realizing MoS2-based FET biosensors with low processing cost and multiplexed detection capabilities.21,189−197 Table 2 presents recent reports on the MoS2-based FET biosensors, sensor material used, and detection limits. Table 2. Recent Reports on MoS2-Based FET Biosensors target streptavidin DNA hybridization PSA tumor necrosis factor-α (TNFα) opioid peptide DAMGO PSA

sensor material Si/SiO2/MoS2/ biotin Si/SiO2/MoS2/ DNA conjugates Si/SiO2/MoS2/ anti-PSA Si/SiO2/MoS2/ HfO2/antiTNF-α Si/SiO2/MoS2/ wsMOR Si/SiO2/MoS2/ HfO2/anti-PSA

detection range

detection limit

ref

100 fM

184

10−100 fM

10 fM

196

1 pg mL−1 to 1 ng mL−1 60 fM to 6 pM

1 pg mL−1 60 fM

21 155

3 nM to 1 μM 3 nM

190

375 fM to 3.75 nM

170

375 fM

4.3. Optical Biosensor. 4.3.1. MoS2 as a Fluorescence Probe. MoS2 has recently found widespread applications as a fluorescence probe in the detection of various biological and environmental analytes (Table 3). As discussed in the previous section, MoS 2 possesses good optical properties like fluorescence and have been utilized to design various sensing 16


Review

ACS Applied Nano Materials Table 3. MoS2 as a Fluorescence Probe for Biosensing Applications dimension 2D

0D 2D

0D 2D

matrix

mode

analyte

single-layer MoS2 MoS2 nanosheets MoS2 nanosheets

turn on turn on turn on

DNA and small biomolecules ssDNA pathogens, S. typhimurium

aptamer-functionalized MoS2 MoS2nanosheets MoS2 nanosheets MoS2/RGO hybrid MoS2 nanosheets MoS2 quantum dot MoS2 nanosheets MoS2 nanosheets boron- and nitride-doped MoS2 nanosheets gold-modified MoS2 hybrid

turn turn turn turn turn turn turn turn turn

PSA DNA detection DNA detection GSH lead(II) hyaluronic acid Ag+ in an aqueous medium and bacteria S2− Hg2+

single-layer MoS2/FA nanosheet MoS2 bio-nanohybrid MoS2 quantum dot MoS2 quantum dot@PANI MoS2@Fe3O4−ICG/PtIV nanoflowers

on on on off on on on off off

induced blue shift NIR imaging NIR imaging imaging imaging imaging

LOD

ref

500 pM 500 pM 10 CFU mL−1 0.2 ng mL−1 0.67 ng mL−1 15 pM 25.0 μM 0.22 μM 0.7 U mL ∼10 nM 0.42 μM 1 nM

199 200 201 202 203 204 205 206 55 207 206 208

DNA detection

209

tissue cancer phototherapy cancer cells SOSG cells cancer cells MR/IR/PA and combined PTT/PDT/chemotherapy triggered by 808 nm laser

210 41 47 211 212

platforms. The art of literature reveals multiple aspects of nanoMoS2 in biosensing applications. On the basis of the morphological characteristics and optical properties, it can be used as either a fluorescence probe or a quencher. Generally, 2D nanosheets have been reportedly used as quenchers in different sensing platforms. The efficiency of MoS2 nanosheets to absorb emissive radiation over a wide range of wavelengths as well as their ability to interact specifically with certain bioentities makes them suitable to act as quenchers. Förster-resonance-energy-transfer-based nanoprobes are known to use MoS2 nanosheets frequently as the fluorescence acceptor in an acceptor−donor couple. On the other hand, quantum-sized 0D MoS2 can be directly used as a sensing probe because of its good fluorescence characteristics. In this section of the paper, we are trying to provide a concise account of the working mechanism of different MoS2-based sensors.198 DNA is one of the most widely reported biomolecules that can be detected by a MoS2 sensing platform with high selectivity and sensitivity. Generally, 2D MoS2 nanosheets have been used as quenchers that work in conjugation with a strongly fluorescent probe. Single-layer MoS2 can be considered to be S−Mo−S sandwich structure in which each molybdenum is coordinated in a trigonal-prismatic geometry to six sulfur atoms. With such unique morphological characteristics, MoS2 nanosheets can specifically absorb single-stranded DNA (ssDNA) via the van der Waals force between nucleobases and the basal plane of MoS2. In most of the cases, the target DNA molecule is labeled with a fluorescent dye or functionalized with a fluorescent nanostructure. As a result of specific MoS2 nanosheets/ssDNA interaction, the fluorescence efficiency of the probe gets hindered, and the diminished intensity can be correlated to the quantitative amount of ssDNA present in the system. Zhu et al. reported the detection of DNA and small biomolecules by using such a technique.199 Huang et al. demonstrated a slightly modified strategy for the detection of ssDNA but with a turn-on type of response (Figure 27).200 A dye-labeled DNA (P1:5′-TAMRA-TGCGAACCAGGAATT-

Figure 27. MoS2/dye-labeled ssDNA (P1). Reprinted with permission from ref 200. Copyright 2014 Royal Society of Chemistry.

3′) was used as the probe for the detection of its complementary DNA (T1:5′-AATTCCTGGTTCGCA-3′). The probe worked at an excitation wavelength of 565 nm with consequent emission at a wavelength of 580 nm. Because of the interaction of P1 and MoS2, the probe fluorescence is quenched. However, in the presence of target DNA, i.e., T1, P1 forms a double-stranded form (dsDNA). Contrary to ssDNA, dsDNA has very weak binding affinity toward MoS2, and, hence, P1/MoS2 interaction is interrogated. As a result, fluorescence is restored, and measurement of the fluorescence intensity provides the quantitative indication of T1.200 Singh et al. used the same technique for detection of pathogen Salmonella typhimurium. A fluorescein-labeled aptamer (AptFAM) was used as the probe for the specific recognition of the pathogen. In the presence of S. typhimurium, the Apt-FAM probe prefers to bind with the target pathogen instead of MoS2 nanosheets. As a result, a turn-on kind of response is achieved. The method can be selectively used for the detection of S. typhimurium over Escherichia coli and Pemphigus vulgaris.201 Kong et al. followed the detection of a prostate-specific antigen (PSA), a biomarker for the early diagnosis of prostate cancer. The quenched fluorescence intensity of a dye-labeled aptamer/ MoS2 sensing platform was restored successfully in the presence of the target PSA.202 17


Review


Figure 28. Band-gap-dependent detection of Hg2+ based on a MoS2-doped sensing probe. Reprinted with permission from ref 208. Copyright 2015 Royal Society of Chemistry.

gives strong fluorescence at an excitation wavelength of 425 nm. However, in the presence of GSH, free-radical reaction gets hindered. GSH scavenges the free radicals, thereby lowering the HTA formation. Consequently, fluorescence is quenched with a turn-off type of response. Thus, measurement of the diminished fluorescence intensity provides a quantitative estimation of GSH.205 On the other hand, MoS2 has been used for bioimaging applications as well. As described in the optical properties segment, MoS2 with variant morphology is suitable for bioimaging applications. Han et al. reported an upconversion multifunctional nanostructure-based bioimaging platform.210 They covalently grafted upconversion nanoparticles with chitosan-functionalized MoS2 (MoS2/CS) and folic acid (FA). The MoS2 surface was loaded with zinc phthalocyanine. The whole nanoassembly was integrated into PDT with photothermal therapy (PTT) and used in upconversion luminescence imaging.209 Similarly, Dong et al. used a MoS2 quantum dot as both conventional and upconversion nanomaterials for bioimaging of SOSG cells.41 Wang and co-workers reported MoS2 quantum dot@PANI (MoS2@PANI) inorganic−organic nanohybrids. Such a nanoassembly exhibits substantial potentiality to enhance the photoaccoustic (PA) imaging/Xray-computed tomography signal as well as perform efficient radiotherapy/PTT of cancer cells.211 Liu et al. designed a multifunctional composite system comprised of MoS2@ Fe3O4−ICG/PtIV (MoS2@Fe-ICG/Pt). Such a nanoassembly was obtained by covalent grafting of Fe3O4 nanoparticles with polyethylenimine-functionalized MoS2 and then loading indocyanine green molecules (ICG, photosensitizers) and platinum(IV) prodrugs (PtIV prodrugs) on the surface of MoS2@Fe3O4. The resultant nanohybrid system of Mo@FeICG/Pt demonstrated good magnetic resonance/IR thermal/ photoacoustic trimodal bioimaging utility.212 4.3.2. Colorimetric Detection. In addition to fluorescencebased techniques, a dimensionally different MoS2 has also been utilized in the colorimetric assay by exploring its useful optical properties. MoS2 possesses a strong characteristic optical absorbance over a wide range of wavelengths. Such a unique absorption of MoS2 can be attributed to the confinement of electronic movements, and the absence of interlayer interference confers monolayer band gaps. Both 0D and 2D MoS2 possess the potential to be used in colorimetric-based biosensing applications. In this context, we highlight a few of the recent reports on MoS2-based colorimetric sensors. It has been reported that 2D TMDs including MoS2 exhibit

In addition to DNA molecules, other bioentities and different environmental analytes have also been detected by using MoS2based sensing platforms. Gu et al. used a MoS2 quantum dot as the fluorescence probe for the detection of hyaluronic acid. Unlike 2D MoS2, this 0D quantum-sized nanoform is soluble in water and, hence, offers further advantages in biosensing applications. The formation of a MoS2 quantum dot/hyaluronic acid/gold nanoparticle nanoassembly leads to fluorescence quenching because of electron transfer from donors (MoS2 quantum dots) to acceptors (hyaluronic acid/gold nanoparticle). Thus, the quantification of a diminished fluorescence intensity (turn-off response) facilitates the detection of hyaluronic acid.55 Similarly, Wang et al. used fluorescent MoS2 nanosheets for the quantitative detection of PbII and S2− ions. They observed that the doping of MoS2 with PbII can significantly enhance the fluorescence properties, while the addition of S2− results in drastic quenching. These properties were explored to develop a MoS2-based sensing platform for the detection of PbII (turn-on response) and S2− ions (turn-off response).206 Yang et al. reported a method for the detection of Ag+ in solution and bacteria. They used rhodamine B isothiocyanate (RhoBS) adsorbed MoS2, which suffers quenching of the fluorescence. On the surface of MoS2, Ag+ undergoes reduction by the action of RhoBS. This resulted in the detachment of silver from the MoS2 surface, restoring the fluorescence intensity (turn-on response).207 Liu et al. modified MoS2 by doping with boron and nitride and used it in the detection of environmental pollutant Hg2+. The whole mechanism relies on band-gap-dependent fluorescence of doped MoS2 (Figure 28). In the pristine state, MoS2 possesses a band gap of 1.20 eV. However, this value increased by up to 1.61 eV after doping with boron and nitride. With the introduction of Hg2+, the band gap decreased significantly with a consequent decrease in the fluorescence intensity. Thus, it offers a turn-off responsedependent detection of Hg2+.208 Literature also shows some exciting detection techniques, where nanostructured MoS2 has been found to play a unique role (other than quencher or probe). For example, Zhang et al. described a nanohybrid comprised of RGO/MoS2 for the detection of GSH that was used as the photocatalyst to produce • OH radicals at the photocatalyst−solution interface in the presence of visible light. Terephthalic acid was used as a working probe, which accepts the free •OH radicals and gets converted into 2-hydroxyterephthalic acid (HTA). HTA is a photoactive compound and 18


Review


ssDNA hybrid in the presence of the target DNA can be utilized for the detection of DNA molecules (Figure 29b).216 Thus, the above motion gives us the impression that, by utilizing the optical properties of MoS2, it is possible to design sensing platforms for various analytes. In this context, understanding of the material properties of dimensionally different MoS2 and their interaction with various bioentities is imperative to obtaining highly sensitive sensing probes.

peroxidase-like catalytic activities, which can be utilized to design various sensing platforms. Recently, Wang et al. reported the detection of FeII by using luminescent MoS2-nanosheetbased peroxidase mimetics. The developed nanosheets possess the ability to catalyze oxidation of the peroxidase substrate ophenylenediamine (OPD) in the presence of H2O2, which gives a yellow product. Fe2+ can enhance the catalytic activity of MoS2 nanosheets greatly and thereby influence the OPD reaction, which can be followed by colorimetric measurements. This constitutes the basis of FeII estimation in a sensitive manner.213 A similar strategy was adopted by Guo et al. showing that MoS2 nanosheets catalyze the reaction of 3,3′,5,5′-tetramethylbenzidine (TMB) with H2O2 to give a blue product, 3,3′,5,5′-tetramethylbenzidinediimine. The formation of this blue product can be followed calorimetrically, which provides a method for the sensitive and selective detection of H2O2.214 Lin et al. followed the same method for the determination of glucose. They combined MoS2nanosheets with GOx, which catalyzes the oxidation of glucose to gluconic acid, and oxygen of the solution is converted into H2O2. The formation of H2O2 depends on the oxidation of glucose present in the system. Thus, the estimation of H2O2 by using TMB provides a quantitative amount of glucose (Figure 29a).215 In

5. CONCLUSION AND FUTURE SCOPES The review addressed the structure, synthesis, and promising biosensing capabilities of MoS2 nanostructures of zero, one, two, and three dimensions. We demonstrated that different dimensions of MoS2 implicate different optical and electrochemical attributes. Electronic and optical properties of MoS2 have been discussed thoroughly with special emphasis on their biosensing potential. This review also highlights the work on electrochemical and fluorescence biosensors based on MoS2 nanostructures. Further, transistor-based biosensors has also been discussed pertaining to the fabrication of biosensing devices. The preparation of composite materials based on dimensionally different MoS 2 may address various advanced applications related to biosensing. All of the dimensions discussed here have been explored to a considerable extent. In the coming years, novel synthetic methods are anticipated to regulate the desired shape and size of MoS2, which will dictate its overall performance as efficient biosensing probes.

■

AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected] (R.K.). ORCID

Shaswat Barua: 0000-0003-0050-3698 Satyabrat Gogoi: 0000-0002-8860-5615 Raju Khan: 0000-0002-3007-0232 Notes

The authors declare no competing financial interest.

■

Figure 29. (a) Colorimetric estimation of H2O2 and glucose. Reprinted with permission from ref 215, Copyright 2014 Royal Society of Chemistry. (b) Utilization of size-dependent optical absorption for the estimation of DNA. Reprinted with permission from ref 216. Copyright 2015 John Wiley and Sons.

ACKNOWLEDGMENTS The Director, CSIR-North East Institute of Science and Technology, Jorhat, is deeply acknowledged for his kind support. S.B. thankfully acknowledges CSIR, India, for a CSIR Nehru Post Doctoral Research Fellowship (HRDG/CSIRNehru PDF/CS/EMR-1/01/2017). S.G. acknowledges SERB, DST, India, for financial support through Grant PDF/2016/ 003142. R.K. acknowledges DBT, India. for financial support through Grant BT/PR16223/NER/95/494/2016.

addition to peroxidase-like catalytic activities, MoS2 also possesses size-dependent optical absorption, which has been utilized in the detection of DNA molecules. In a salt solution, 2D MoS2 exhibits a tendency to agglomerate and often forms larger aggregates than those in an aqueous medium. As a result, the optical absorption capacity decreases considerably. However, upon functionalization with ssDNA, such a tendency of MoS2 gets hindered, and the original light absorption ability is restored. However, in the presence of target DNA, 2D MoS2 again forms aggregates, leading to a decrease in the optical absorbance. Thus, diminished optical absorption of the MoS2/

(1) Mehrotra, P. Biosensors and their Applications. J. Oral Biol. Craniofac. Res. 2016, 6, 153−159. (2) Zhang, D.; Ouyang, X.; Li, L.; Dai, B.; Zhang, Y. Real-time Amperometric Monitoring of Cellular Hydrogen Peroxide Based on Electrodeposited Reduced Graphene Oxide Incorporating Adsorption of Electroactive Methylene Blue Hybrid Composites. J. Electroanal. Chem. 2016, 780, 60−67. (3) Turner, A. P. F. Biosensors: Sense and Sensibility. Chem. Soc. Rev. 2013, 42, 3184−3196. (4) Peppas, N. A.; Van Blarcom, D. S. Hydrogel-Based Biosensors and Sensing Devices for Drug Delivery. J. Controlled Release 2016, 240, 142−150.

■

19

REFERENCES


Review


Pancreatic Cancer Biomarker CA19−9. ACS Appl. Mater. Interfaces 2017, 9, 25878−25886. (25) Hu, J.; Odom, T. W.; Lieber, C. M. Chemistry and Physics in One Dimension: Synthesis and Properties of Nanowires and Nanotubes. Acc. Chem. Res. 1999, 32, 435−445. (26) Doria, G.; Conde, J.; Veigas, B.; Giestas, L.; Almeida, C.; Assuncao, M.; Rosa, J.; Baptista, P. V. Noble Metal Nanoparticles for Biosensing Applications. Sensors 2012, 12, 1657−1687. (27) Bai, J.; Zhou, B. Titanium Dioxide Nanomaterials for Sensor Applications. Chem. Rev. 2014, 114, 10131−10176. (28) Thompson, R. B.; Jones, E. R. Enzyme-Based Fiber Optic Zinc Biosensor. Anal. Chem. 1993, 65, 730−734. (29) Kaushik, A.; Khan, R.; Solanki, P. R.; Pandey, P.; Alam, J.; Ahmad, S.; Malhotra, B. D. Iron Oxide Nanoparticles-Chitosan Composite Based Glucose Biosensor. Biosens. Bioelectron. 2008, 24, 676−683. (30) Lin, Y. C.; Zhang, W.; Huang, J. K.; Liu, K. K.; Lee, Y. H.; Liang, C. T.; Chu, C. W.; Li, L. J. Wafer-Scale MoS2 Thin Layers Prepared by MoO3 Sulfurization. Nanoscale 2012, 4, 6637−6641. (31) Chou, J.; Yang, H.; Chen, C. Glucose Biosensor of RutheniumDoped TiO2 Sensing Electrode by Co-Sputtering System. Microelectron. Reliab. 2010, 50, 753−756. (32) Seifert, G.; Terrones, H.; Terrones, M.; Jungnickel, G.; Frauenheim, T. Structure and Electronic Properties of MoS 2 Nanotubes. Phys. Rev. Lett. 2000, 85, 146−149. (33) Margulis, L.; Salitra, G.; Tenne, R.; Talianker, M. Nested Fullerene-Like Structures. Nature 1993, 365, 113−114. (34) Albu-Yaron, A.; Levy, M.; Tenne, R.; Popovitz-Biro, R.; Weidenbach, M.; Bar-Sadan, M.; Houben, L.; Enyashin, A. N.; Seifert, G.; Feuermann, D.; Katz, E. A.; Gordon, J. M. MoS2 Hybrid Nanostructures: From Octahedral to Quasi-Spherical Shells within Individual Nanoparticles. Angew. Chem., Int. Ed. 2011, 50, 1810−1814. (35) Tenne, R. Doped and Heteroatom-Containing Fullerene-Llike Structures and Nanotubes. Adv. Mater. 1995, 7, 965−995. (36) Enyashin, A. N.; Gemming, S.; Bar-Sadan, M.; Popovitz-Biro, R. P.; Hong, S. Y.; Prior, Y.; Tenne, R.; Seifert, G. Structure and Stability of Molybdenum Sulfide Fullerenes. Angew. Chem., Int. Ed. 2007, 46, 623−627. (37) Alexandrou, I.; Sano, N.; Burrows, A.; Meyer, R. R.; Wang, H.; Kirkland, A. I.; Kiely, C. J.; Amaratunga, G. A. J. Structural Investigation of MoS2 Core-Shell Nanoparticles Formed by an Arc Discharge in Water. Nanotechnology 2003, 14, 913. (38) Wilcoxon, J. P.; Samara, G. A. Strong Quantum-Size Effects in a Layered Semiconductor: MoS2 Nanoclusters. Phys. Rev. B: Condens. Matter Mater. Phys. 1995, 51, 7299−7302. (39) Chhowalla, M.; Amaratunga, G. A. Thin Films of Fullerene-Like MoS2 Nanoparticles with Ultra-Low Friction and Wear. Nature 2000, 407, 164−167. (40) Li, Y.; Wang, H.; Xie, L.; Liang, Y.; Hong, G.; Dai, H. MoS2 Nanoparticles Grown on Graphene: An Advanced Catalyst for the Hydrogen Evolution Reaction. J. Am. Chem. Soc. 2011, 133, 7296− 7299. (41) Dong, H.; Tang, S.; Hao, Y.; Yu, H.; Dai, W.; Zhao, G.; Cao, Y.; Lu, H.; Zhang, X.; Ju, H. Fluorescent MoS2 Quantum Dots: Ultrasonic Preparation, Up-conversion and Down-conversion Bioimaging, and Photodynamic Therapy. ACS Appl. Mater. Interfaces 2016, 8, 3107− 3114. (42) Xu, S.; Li, D.; Wu, P. One-Pot, Facile, and Versatile Synthesis of Monolayer MoS2 /WS2 Quantum Dots as Bioimaging Probes and Efficient Electrocatalysts for Hydrogen Evolution Reaction. Adv. Funct. Mater. 2015, 25, 1127−1136. (43) Dai, W.; Dong, H.; Fugetsu, B.; Cao, Y.; Lu, H.; Ma, X.; Zhang, X. Tunable Fabrication of Molybdenum Disulfide Quantum Dots for Intracellular Micro RNA Detection and Multiphoton Bioimaging. Small 2015, 11, 4158−4164. (44) Kufer, D.; Nikitskiy, I.; Lasanta, T.; Navickaite, G.; Koppens, F. H. L.; Konstantatos, G. Hybrid 2D−0D MoS2 − PbS Quantum Dot Photodetectors. Adv. Mater. 2015, 27, 176−180.

(5) Jianrong, C.; Yuqing, M.; Nongyue, H.; Xiaohua, W.; Sijiao, L. Nanotechnology and Biosensors. Biotechnol. Adv. 2004, 22, 505−518. (6) Aydemir, N.; Malmstrom, J.; Travas-Sejdic, J. Conducting Polymer Based Electrochemical Biosensors. Phys. Chem. Chem. Phys. 2016, 18, 8264−8277. (7) Zhang, G.; Liu, H.; Qu, J.; Li, J. Two-Dimensional Layered MoS2: Rational Design, Properties and Electrochemical Applications. Energy Environ. Sci. 2016, 9, 1190−1209. (8) Lin, Y. C.; Dumcenco, D. O.; Huang, Y. S.; Suenaga, K. Atomic Mechanism of the Semiconducting-to-Metallic Phase Transition in Single-Layered MoS2. Nat. Nanotechnol. 2014, 9, 391−396. (9) He, Q.; Zeng, Z.; Yin, Z.; Li, H.; Wu, S.; Huang, X.; Zhang, H. Fabrication of Flexible MoS2 Thin-Film Transistor Arrays for Practical Gas-Sensing Applications. Small 2012, 8, 2994−2999. (10) Li, N.; Lee, G.; Jeong, Y. H.; Kim, K. S. Tailoring electronic and magnetic properties of MoS2 nanotubes. J. Phys. Chem. C 2015, 119, 6405−6413. (11) Zhang, X.; Lai, Z.; Tan, C.; Zhang, H. Solution-Processed TwoDimensional MoS2 Nanosheets: Preparation, Hybridization, and Applications. Angew. Chem., Int. Ed. 2016, 55, 8816−8838. (12) Xing, W.; Chen, Y.; Wang, X.; Lv, L.; Ouyang, X.; Ge, Z.; Huang, H. MoS2 quantum dots with a tunable work function for highperformance organic solar cells. ACS Appl. Mater. Interfaces 2016, 8, 26916−26923. (13) Feldman, Y.; Frey, G. L.; Homyonfer, M.; Lyakhovitskaya, V.; Margulis, L.; Cohen, H.; Hodes, G.; Hutchison, J. L.; Tenne, R. Bulk Synthesis of Inorganic Fullerene-like MS2 (M = Mo, W) from the Respective Trioxides and the Reaction Mechanism. J. Am. Chem. Soc. 1996, 118, 5362−5367. (14) Hershfinkel, M.; Gheber, L. A.; Volterra, V.; Hutchison, J. L.; Margulis, L.; Tenne, R. J. Nested Polyhedra of MX2 (M = W, Mo; X = S, Se) Probed by High-Resolution Electron Microscopy and Scanning Tunneling Microscopy. J. Am. Chem. Soc. 1994, 116, 1914−1917. (15) Scheffer, L.; Rosentzveig, R.; Margolin, A.; Popovitz-Biro, R.; Seifert, G.; Cohen, S. R.; Tenne, R. Scanning tunneling microscopy study of WS2 nanotubes. Phys. Chem. Chem. Phys. 2002, 4, 2095− 2098. (16) Xiao, L.; Xu, L.; Gao, C.; Zhang, Y.; Yao, Q.; Zhang, G. J. A MoS2 Nanosheet-Based Fluorescence Biosensor for Simple and Quantitative Analysis of DNA Methylation. Sensors 2016, 16, 1561− 1571. (17) Zhu, C.; Zeng, Z.; Li, H.; Li, F.; Fan, C.; Zhang, H. Single-layer MoS2-based Nanoprobes for Homogeneous Detection of Biomolecules. J. Am. Chem. Soc. 2013, 135, 5998−6001. (18) Xiang, X.; Shi, J.; Huang, F.; Zheng, M.; Deng, Q.; Xu, J. MoS2 Nanosheet-Based Fluorescent Biosensor for Protein Detection via Terminal Protection of Small-Molecule-Linked DNA and Exonuclease III-Aided DNA Recycling Amplification. Biosens. Bioelectron. 2015, 74, 227−232. (19) Kalantar-zadeh, K.; Ou, J. Z. Biosensors Based on TwoDimensional MoS2. ACS Sens. 2016, 1, 5−16. (20) Sun, H.; Chao, J.; Zuo, X.; Su, S.; Liu, X.; Yuwen, L.; Fan, C.; Wang, L. Gold Nanoparticle-Decorated MoS2 Nanosheets for Simultaneous Detection of Ascorbic Acid, Dopamine and Uric Acid. RSC Adv. 2014, 4, 27625−27629. (21) Ha, H. D.; Han, D. J.; Choi, J. S.; Park, M.; Seo, T. S. Dual Role of Blue Luminescent MoS2 Quantum Dots in Fluorescence Resonance Energy Transfer Phenomenon. Small 2014, 10, 3858−3862. (22) Zhang, X.; Lai, Z.; Liu, Z.; Tan, C.; Huang, Y.; Li, B.; Zhao, M.; Xie, L.; Huang, W.; Zhang, H. A Facile and Universal Top-Down Method for Preparation of Monodisperse Transition-Metal Dichalcogenide Nanodots. Angew. Chem., Int. Ed. 2015, 54, 5425−5428. (23) Wang, J.; Liu, G.; Jan, M. R. Ultrasensitive Electrical Biosensing of Proteins and DNA: Carbon-Nanotube Derived Amplification of the Recognition and Transduction Events. J. Am. Chem. Soc. 2004, 126, 3010−3011. (24) Thapa, A.; Soares, A. C.; Soares, J. C.; Awan, I. T.; Volpati, D.; Melendez, M. E.; Fregnani, J. H. T. G.; Carvalho, A. L.; Oliveira, O. N., Jr Carbon Nanotube Matrix for Highly Sensitive Biosensors To Detect 20


Review


(65) Ghorbani-Asl, M. A.; Zibouche, N.; Wahiduzzaman, M.; Oliveira, A. F.; Kuc, A.; Heine, T. Electromechanics in MoS2 and WS2: Nanotubes Vs. Monolayers. Sci. Rep. 2013, 3, 2961−2969. (66) Nath, M.; Govindaraj, A.; Rao, C. N. R. Simple Synthesis of MoS2 and WS2 Nanotubes. Adv. Mater. 2001, 13, 283−286. (67) Remikar, M.; Skraba, Z.; Regula, M.; Ballif, C.; Sanjines, R.; Levy, F. New Crystal Structures of WS2: Microtubes, Ribbons, and Ropes. Adv. Mater. 1998, 10, 246−249. (68) Remskar, M.; Mrzel, A.; Skraba, Z.; Jesih, A.; Ceh, M.; Demsar, J.; Stadelmann, P.; Levy, F.; Mihailovic, D. Self-Assembly of Subnanometer-Diameter Single-Wall MoS2 Nanotubes. Science 2001, 292, 479−481. (69) Song, X. C.; Zheng, Y. F.; Zhao, Y.; Yin, H. Y. Hydrothermal Synthesis and Characterization of CNT@MoS2 Nanotubes. Mater. Lett. 2006, 60, 2346−2348. (70) Zhang, C.; Wang, Z.; Guo, Z.; Lou, X. W. Synthesis of MoS2−C one-dimensional nanostructures with improved lithium storage properties. ACS Appl. Mater. Interfaces 2012, 4, 3765−3768. (71) Yang, L.; Wang, S.; Mao, J.; Deng, J.; Gao, Q.; Tang, Y.; Schmidt, O. G. Hierarchical MoS 2 /Polyaniline Nanowires with Excellent Electrochemical Performance for Lithium-Ion Batteries. Adv. Mater. 2013, 25, 1180−1184. (72) Li, G.; Zeng, X.; Zhang, T.; Ma, W.; Li, W.; Wang, M. synthesis of hierarchical hollow MoS2 nanotubes as anode materials for highperformance lithium-ion batteries. CrystEngComm 2014, 16, 10754− 10759. (73) Fathipour, S.; Remskar, M.; Varlec, A.; Ajoy, A.; Yan, R.; Vishwanath, S.; Rouvimov, S.; Hwang, W. S.; Xing, H. G.; Jena, D.; Seabaugh, A. Synthesized Multiwall MoS2 Nanotube and Nanoribbon Field-Effect Transistors. Appl. Phys. Lett. 2015, 106, 022114. (74) Barua, S.; Thakur, S.; Aidew, L.; Buragohain, A. K.; Chattopadhyay, P.; Karak, N. One Step Preparation of a Biocompatible, Antimicrobial Rreduced Graphene Oxide-Silver Nanohybrid as a Topical Antimicrobial Agent. RSC Adv. 2014, 4, 9777− 9783. (75) Barua, S.; Chattopadhyay, P.; Phukan, M. M.; Konwar, B. K.; Islam, J.; Karak, N. Biocompatible Hyperbranched Epoxy/SilverReduced Graphene Oxide-Curcumin Nanocomposite as an Advanced Antimicrobial Material. RSC Adv. 2014, 4, 47797−47805. (76) Tan, C.; Zhang, H. Two-Dimensional Transition Metal Dichalcogenide Nanosheet-based Composites. Chemical. Chem. Soc. Rev. 2015, 44, 2713−2731. (77) Yan, Y.; Xia, B.; Ge, X.; Liu, Z.; Wang, J. Y.; Wang, X. (2013). Ultrathin MoS2 Nanoplates with Rich Active Sites as Highly Efficient Catalyst for Hydrogen Evolution. ACS Appl. Mater. Interfaces 2013, 5, 12794−12798. (78) Jariwala, D.; Sangwan, V. K.; Lauhon, L. J.; Marks, T. J.; Hersam, M. C. Emerging device applications for semiconducting twodimensional transition metal dichalcogenides. ACS Nano 2014, 8, 1102−1120. (79) Wang, Q. H.; Kalantar-Zadeh, K.; Kis, A.; Coleman, J. N.; Strano, M. S. Electronics and Optoelectronics of Two-Dimensional Transition Metal Dichalcogenides. Nat. Nanotechnol. 2012, 7, 699− 704. (80) Yu, Y.; Li, C.; Liu, Y.; Su, L.; Zhang, Y.; Cao, L. Controlled Scalable Synthesis of Uniform, High-Quality Monolayer and FewLayer MoS2 Films. Sci. Rep. 2013, 3, 1866−1872. (81) Mishra, A. K.; Lakshmi, K. V.; Huang, L. Eco-Friendly Synthesis of Metal Dichalcogenides Nanosheets and Their Environmental Remediation Potential Driven By Visible Light. Sci. Rep. 2015, 5, 15718−15726. (82) Chhowalla, M.; Shin, H. S.; Eda, G.; Li, L. J.; Loh, K. P.; Zhang, H. The Chemistry of Two-Dimensional Layered Transition Metal Dichalcogenide Nanosheets. Nat. Chem. 2013, 5, 263−275. (83) Novoselov, K. S.; Jiang, D.; Schedin, F.; Booth, T. J.; Khotkevich, V. V.; Morozov, S. V.; Geim, A. K. Two-Dimensional Atomic Crystals. Proc. Natl. Acad. Sci. U. S. A. 2005, 102, 10451− 10453.

(45) Wang, Y.; Ni, Y. Molybdenum Disulfide Quantum Dots as a Photoluminescence Sensing Platform for 2,4,6-trinitrophenol Detection. Anal. Chem. 2014, 86, 7463−7470. (46) Gopalakrishnan, D.; Damien, D.; Shaijumon, M. M. Shaijumon, MoS2 Quantum Dot-Interspersed Exfoliated MoS2 Nanosheets. ACS Nano 2014, 8, 5297−5303. (47) Liu, T.; Chao, Y.; Gao, M.; Liang, C.; Chen, Q.; Song, G.; Cheng, L.; Liu, Z. Ultra-small MoS2 nanodots with rapid body clearance for photothermal cancer therapy. Nano Res. 2016, 9, 3003− 3017. (48) Eda, G.; Yamaguchi, H.; Voiry, D.; Fujita, T.; Chen, M. W.; Chhowalla, M. Photoluminescence from Chemically Exfoliated MoS2. Nano Lett. 2011, 11, 5111−5116. (49) Li, H.; Yin, Z. Y.; He, Q. Y.; Li, H.; Huang, X.; Lu, G.; Fam, D. W. H.; Tok, A. I. Y.; Zhang, Q.; Zhang, H. Fabrication of single- and multilayer MoS2 film-based field-effect transistors for sensing NO at room temperature. Small 2012, 8, 63−67. (50) Nicolosi, V.; Chhowalla, M.; Kanatzidis, M. G.; Strano, M. S.; Coleman, J. N. Liquid Exfoliation of Layered Materials. Science 2013, 340, 1226419. (51) Smith, R. J.; King, P. J.; Lotya, M.; Wirtz, C.; Khan, U.; De, S.; O’Neill, A.; Duesberg, G. S.; Grunlan, J. C.; Moriarty, G.; Chen, J.; Wang, J.; Minett, A. I.; Nicolosi, V.; Coleman, J. N. Large-Scale Exfoliation of Inorganic Layered Compounds in Aqueous Surfactant Solutions. Adv. Mater. 2011, 23, 3944−3948. (52) Lee, Y. H.; Zhang, X. Q.; Zhang, W. J.; Chang, M. T.; Lin, C. T.; Chang, K. D.; Yu, Y. C.; Wang, J. T. W.; Chang, C. S.; Li, L. J.; Lin, T. W. Synthesis of Large-Area MoS2 Atomic Layers with Chemical Vapor Deposition. Adv. Mater. 2012, 24, 2320−2325. (53) Altavilla, C.; Sarno, M.; Ciambelli, P. A Novel Wet Chemistry Approach for the Synthesis of Hybrid 2D Free-Floating Single or Multilayer Nanosheets of MS2@oleylamine (MMo, W). Chem. Mater. 2011, 23, 3879−3885. (54) Peng, Y. Y.; Meng, Z. Y.; Zhong, C.; Lu, J.; Yu, W. C.; Jia, Y. B.; Qian, Y. T. Hydrothermal Synthesis and Characterization of SingleMolecular-Layer MoS2 and MoSe2. Chem. Lett. 2001, 30, 772−773. (55) Gu, W.; Yan, Y.; Zhang, C.; Ding, C.; Xian, Y. One-Step Synthesis of Water-Soluble MoS2 Quantum Dots via a Hydrothermal Method as a Fluorescent Probe for Hyaluronidase Detection. ACS Appl. Mater. Interfaces 2016, 8, 11272−11279. (56) Lin, H.; Wang, C.; Wu, J.; Xu, Z.; Huang, Y.; Zhang, C. Colloidal synthesis of MoS2 Quantum Dots: Size-Dependent Tunable Photoluminescence and Bioimaging. New J. Chem. 2015, 39, 8492− 8497. (57) Stengl, V.; Henych, J. Strongly luminescent Monolayered MoS2 Prepared by Effective Ultrasound Exfoliation. Nanoscale 2013, 5, 3387−3394. (58) Goswami, N.; Giri, A.; Pal, S. K. MoS2 Nanocrystals Confined in a DNA Matrix Exhibiting Energy Transfer. Langmuir 2013, 29, 11471−11478. (59) Zhu, Y. Q.; Hsu, W. K.; Grobert, N.; Chang, B. H.; Terrones, M.; Terrones, H.; Kroto, H. W.; Walton, D. R. M.; Wei, B. Q. Production of WS2 Nanotubes. Chem. Mater. 2000, 12, 1190−1194. (60) Milosevic, I.; Nikolic, B.; Dobardzic, E.; Damnjanovic, M.; Popov, I.; Seifert, G. Electronic Properties and Optical Spectra of MoS2 and WS2 Nanotubes. Phys. Rev. B: Condens. Matter Mater. Phys. 2007, 76, 233414. (61) Zibouche, N.; Kuc, A.; Heine, T. From Layers to Nanotubes: Transition Metal Disulfides TMS2. Eur. Phys. J. B 2012, 85, 49. (62) Remskar, M.; Mrzel, A.; Virsek, M.; Godec, M.; Krause, M.; Kolitsch, A.; Singh, A.; Seabaugh, A. The MoS2 Nanotubes with Defect-Controlled Electric Properties. Nanoscale Res. Lett. 2010, 6, 26. (63) Tenne, R.; Margulis, L.; Genut, M.; Hodes, G. Polyhedral and Cylindrical Structures of Tungsten Disulphide. Nature 1992, 360, 444−446. (64) Margulis, L.; Dluzewski, P.; Feldman, Y.; Tenne, R. TEM Study of Chirality in MoS2 Nanotubes. J. Microsc. 1996, 181, 68−71. 21


Review

ACS Applied Nano Materials (84) Xu, M.; Liang, T.; Shi, M.; Chen, H. Graphene-Like TwoDimensional Materials. Chem. Rev. 2013, 113, 3766−3798. (85) Coleman, J. N.; et al. Two-Dimensional Nanosheets Produced By Liquid Exfoliation of Layered Materials. Science 2011, 331, 568− 571. (86) Varrla, E.; Backes, C.; Paton, K. R.; Harvey, A.; Gholamvand, Z.; McCauley, J.; Coleman, J. N. Large-scale production of size-controlled MoS2 nanosheets by shear exfoliation. Chem. Mater. 2015, 27, 1129− 1139. (87) Forsberg, V.; Zhang, R.; Bäckstrom, J.; Dahlstrom, C.; Andres, B.; Norgren, M.; Andersson, M.; Hummelgard, M.; Olin, H. Exfoliated MoS2 in Water without Additives. PLoS One 2016, 11, e0154522. (88) Zeng, Z.; Yin, Z.; Huang, X.; Li, H.; He, Q.; Lu, G.; Boey, F.; Zhang, H. Single-Layer Semiconducting Nanosheets: High-Yield Preparation And Device Fabrication. Angew. Chem., Int. Ed. 2011, 50, 11093−11097. (89) Liu, K. K.; Zhang, W.; Lee, Y. H.; Lin, Y. C.; Chang, M. T.; Su, C. Y.; Chang, C. S.; Li, H.; Shi, Y.; Zhang, H.; Lai, C. S.; Li, L. J. Growth of Large-Area and Highly Crystalline MoS2 Thin Layers on Insulating Substrates. Nano Lett. 2012, 12, 1538−1544. (90) Zhou, K. G.; Mao, N. N.; Wang, H. X.; Peng, Y.; Zhang, H. L. A Mixed-Solvent Strategy for Efficient Exfoliation Of Inorganic Graphene Analogues. Angew. Chem., Int. Ed. 2011, 50, 10839−10842. (91) Geng, X.; Wu, W.; Li, N.; Sun, W.; Armstrong, J.; Al-hilo, A.; Brozak, M.; Cui, J.; Chen, T.-p. Three-Dimensional Structures of MoS2 Nanosheets with Ultrahigh Hydrogen Evolution Reaction in Water Reduction. Adv. Funct. Mater. 2014, 24, 6123−6129. (92) Zhang, R.; Wan, W.; Li, D.; Dong, F.; Zhou, Y. Threedimensional MoS2/Reduced Graphene Oxide Aerogel As A Macroscopic Visible-Light Photocatalyst. Chin. J. Catal. 2017, 38, 313−320. (93) Wang, P. P.; Sun, H.; Ji, Y.; Li, W.; Wang, X. Three-Dimensional Assembly of Single-Layered MoS2. Adv. Mater. 2014, 26, 964−969. (94) Xiong, F.; Cai, Z.; Qu, L.; Zhang, P.; Yuan, Z.; Asare, O. K.; Xu, W.; Lin, C.; Mai, L. Three-Dimensional Crumpled Reduced Graphene Oxide/MoS2 Nanoflowers: A Stable Anode For Lithium-Ion Batteries. ACS Appl. Mater. Interfaces 2015, 7, 12625−12630. (95) Lu, X.; Lin, Y.; Dong, H.; Dai, W.; Chen, X.; Qu, X.; Zhang, X. One-Step Hydrothermal Fabrication of Three-dimensional MoS2 Nanoflower using Polypyrrole as Template for Efficient Hydrogen Evolution Reaction. Sci. Rep. 2017, 7, 42309−42317. (96) Yang, L.; Zhou, W.; Hou, D.; Zhou, K.; Li, G.; Tang, Z.; Li, L.; Chen, S. Porous Metallic MoO2-Supported MoS2 Nanosheets for Enhanced Electrocatalytic Activity in the Hydrogen Evolution Reaction. Nanoscale 2015, 7, 5203−5208. (97) Kong, D.; Wang, H.; Cha, J. J.; Pasta, M.; Koski, K. J.; Yao, J.; Cui, Y. Synthesis of MoS2 and MoSe2 Films With Vertically Aligned Layers. Nano Lett. 2013, 13, 1341−1347. (98) Zhang, N.; Ma, W.; Wu, T.; Wang, H.; Han, D.; Niu, L. EdgeRich MoS2 Naonosheets Rooting into Polyaniline Nanofibers as Effective Catalyst for Electrochemical Hydrogen Evolution. Electrochim. Acta 2015, 180, 155−163. (99) Nikam, R. D.; Lu, A. Y.; Sonawane, P. A.; Kumar, U. R.; Yadav, K.; Li, L. J.; Chen, Y. T. Three-dimensional heterostructures of MoS2 nanosheets on conducting MoO2 as an efficient electrocatalyst to enhance hydrogen evolution reaction. ACS Appl. Mater. Interfaces 2015, 7, 23328−23335. (100) Jaramillo, T. F.; Jørgensen, K. P.; Bonde, J.; Nielsen, J. H.; Horch, S.; Chorkendorff, I. Identification of Active Edge Sites for Electrochemical H2 Evolution from MoS2 Nanocatalysts. Science 2007, 317, 100−102. (101) Tian, R.; Wang, W.; Huang, Y.; Duan, H.; Guo, Y.; Kang, H.; Li, H.; Liu, H. 3D Composites of Layered MoS2 and Graphene Nanoribbons for High Performance Lithium-Ion Battery Anodes. J. Mater. Chem. A 2016, 4, 13148−13154. (102) Chang, Y. H.; Nikam, R. D.; Lin, C. T.; Huang, J. K.; Tseng, C. C.; Hsu, C. L.; Cheng, C. C.; Su, C. Y.; Li, L. J.; Chua, D. H. C. Enhanced Electrocatalytic Activity of MoSx on TCNQ-Treated Electrode For Hydrogen Evolution Reaction. ACS Appl. Mater. Interfaces 2014, 6, 17679−17685.

(103) Kuc, A.; Zibouche, N.; Heine, T. Influence of Quantum Confinement on the Electronic Structure Of The Transition Metal Sulfide TS2. Phys. Rev. B: Condens. Matter Mater. Phys. 2011, 83, 245213. (104) Han, S. W.; Kwon, H.; Kim, S. K.; Ryu, S.; Yun, W. S.; Kim, D. H.; Hwang, J. H.; Kang, J. S.; Baik, J.; Shin, H. J.; Hong, S. C. BandGap Transition Induced by Interlayer Van Der Waals Interaction In MoS2. Phys. Rev. B: Condens. Matter Mater. Phys. 2011, 84, 045409. (105) Han, S. W.; Cha, G. B.; Frantzeskakis, E.; Razado-Colambo, I.; Avila, J.; Park, Y. S.; Kim, D.; Hwang, J.; Kang, J. S.; Ryu, S.; Yun, W. S.; Hong, S. C.; Asensio, M. C. Band-Gap Expansion In The SurfaceLocalized Electronic Structure Of MoS2 (0002). Phys. Rev. B: Condens. Matter Mater. Phys. 2012, 86, 115105. (106) Kadantsev, E. S.; Hawrylak, P. Electronic Structure of A Single Mos2 Monolayer. Solid State Commun. 2012, 152, 909−913. (107) Cheiwchanchamnangij, T.; Lambrecht, W. R. L. Quasiparticle Band Structure Calculation Of Monolayer, Bilayer, And Bulk MoS2. Phys. Rev. B: Condens. Matter Mater. Phys. 2012, 85, 205302. (108) Komsa, H. P.; Krasheninnikov, A. V. Effects of confinement and environment on the electronic structure and exciton binding energy of MoS2 from first principles. Phys. Rev. B: Condens. Matter Mater. Phys. 2012, 86, 241201. (109) Radisavljevic, B.; Radenovic, A.; Brivio, J.; Giacometti, V.; Kis, A. Single-layer MoS2 transistors. Nat. Nanotechnol. 2011, 6, 147−150. (110) Tsai, D. S.; Lien, D. H.; Tsai, M. L.; Su, S. H.; Chen, K. M.; Ke, J. J.; Yu, Y. C.; Li, L. J.; He, J. H. Trilayered MoS2 MetalSemiconductor Metal Photodetectors: Photogain and Radiation Resistance. IEEE J. Sel. Top. Quantum Electron. 2014, 20, 30. (111) Kang, M.; Kim, Y. A.; Yun, J. M.; Khim, D.; Kim, J.; Noh, Y. Y.; Baeg, K. J.; Kim, D. Y. Stable Charge Storing in Two-Dimensional MoS2 Nanoflake Floating Gates for Multilevel Organic Flash Memory. Nanoscale 2014, 6, 12315−12323. (112) Wang, R.; Ruzicka, B. A.; Kumar, N.; Bellus, M. Z.; Chiu, H. Y.; Zhao, H. Ultrafast and Spatially Resolved Studies of Charge Carriers in Atomically Thin Molybdenum Disulfide. Phys. Rev. B: Condens. Matter Mater. Phys. 2012, 86, 045406. (113) Liu, L.; Lu, Y.; Guo, J. On Monolayer MoS2 Field-Effect Transistors at the Scaling Limit. IEEE Trans. Electron Devices 2013, 60, 4133−4139. (114) Desai, S. B.; Madhvapathy, S. R.; Sachid, A. B.; Llinas, J. P.; Wang, Q.; Ahn, G. H.; Pitner, G.; Kim, M. J.; Bokor, J.; Hu, C.; Wong, H. S. P.; Javey, A. MoS2 Transistors with 1-Nanometer Gate Lengths. Science 2016, 354, 99−102. (115) Yu, Z.; Ong, Z. Y.; Li, S.; Xu, J. B.; Zhang, G.; Zhang, Y. W.; Shi, Y.; Wang, X. Analyzing the Carrier Mobility in Transition-Metal Dichalcogenide MoS2 Field-Effect Transistors. Adv. Funct. Mater. 2017, 27, 1604093. (116) Franklin, A. D. Nanomaterials in transistors: From HighPerformance to Thin-Film Applications. Science 2015, 349, aab2750. (117) Laursen, A. B.; Kegnaes, S.; Dahl, S.; Chorkendorff, I. Molybdenum sulfides-efficient and viable materials for electro-and photoelectrocatalytic hydrogen evolution. Energy Environ. Sci. 2012, 5, 5577−5591. (118) Hinnemann, B.; Moses, P. G.; Bonde, J.; Jorgensen, K. P.; Nielsen, J. H.; Horch, S.; Chorkendorff, I.; Norskov, J. K. Biornimetic hydrogen evolution: MoS2 nanoparticles as catalyst for hydrogen evolution. J. Am. Chem. Soc. 2005, 127, 5308−5309. (119) Vrubel, H.; Merki, D.; Hu, X. L. Hydrogen evolution catalyzed by MoS3 and MoS2 particles. Energy Environ. Sci. 2012, 5, 6136−6144. (120) Bonde, J.; Moses, P. G.; Jaramillo, T. F.; Norskov, J. K.; Chorkendorff, I. Hydrogen evolution on nano-particulate transition metal sulfides. Faraday Discuss. 2009, 140, 219−231. (121) Kibsgaard, J.; Chen, Z. B.; Reinecke, B. N.; Jaramillo, T. F. Engineering the surface structure of MoS2 to preferentially expose active edge sites for electrocatalysis. Nat. Mater. 2012, 11, 963−969. (122) Chen, Z. B.; Cummins, D.; Reinecke, B. N.; Clark, E.; Sunkara, M. K.; Jaramillo, T. F. Core-shell MoO3-MoS2 Nanowires for Hydrogen Evolution: A Functional Design for Electrocatalytic Materials. Nano Lett. 2011, 11, 4168−4175. 22


Review


Te) from ab-initio theory: new direct band gap semiconductors. Eur. Phys. J. B 2012, 85, 186. (143) Tadi, K. K.; Palve, A. M.; Pal, S.; Sudeep, P. M.; Narayanan, T. N. Single Step, Bulk Synthesis of Engineered MoS2 Quantum Dots for Multifunctional Electrocatalysis. Nanotechnology 2016, 27, 275402. (144) Kalantar-zadeh, K.; Ou, J. Z.; Daeneke, T.; Strano, M. S.; Pumera, M.; Gras, S. L. Two-Dimensional Transition Metal Dichalcogenides in Biosystems. Adv. Funct. Mater. 2015, 25, 5086− 5099. (145) Ravula, S.; Essner, J. B.; Baker, G. A. Kitchen-Inspired Nanochemistry: Dispersion, Exfoliation, and Hybridization of Functional MoS2 Nanosheets using Culinary Hydrocolloids. Chem. Nano. Mater. 2015, 1, 167−177. (146) Li, F.; Zhang, L.; Li, J.; Lin, X.; Li, X.; Fang, Y.; Huang, J.; Li, W.; Tian, M.; Jin, J.; Li, R. Synthesis of CueMoS2/rGO hybrid as nonnoble metal electro catalysts for the hydrogen evolution reaction. J. Power Sources 2015, 292, 15−22. (147) Rohaizad, N.; Mayorga-Martinez, C. C.; Sofer, Z.; Pumera, M. 1T-Phase Transition Metal Dichalcogenides (MoS2, MoSe2, WS2, and WSe2) with Fast Heterogeneous Electron Transfer: Application on Second-Generation Enzyme-Based Biosensor. ACS Appl. Mater. Interfaces 2017, 9, 40697−40706. (148) Khan, R.; Gorski, W.; Garcia, C. D. Nanomolar Detection of Glutamate at a Biosensor Based on Screen-Printed Electrodes Modified with Carbon Nanotubes. Electroanalysis 2011, 23, 2357− 2363. (149) Khan, R. Supported TritonX-100 Polyaniline Nano-Porous Electrically Active Film onto Indium-Tin-Oxide Probe for Sensors Application. Adv. Chem. Eng. Sci. 2011, 01, 140−146. (150) Sharma, A.; Kumar, A.; Khan, R. Electrochemical immunosensor based on poly (3, 4-ethylenedioxythiophene) modified with gold nanoparticle to detect aflatoxin B 1. Mater. Sci. Eng., C 2017, 76, 802−809. (151) Wang, L.; Wang, Y.; Wong, J. I.; Palacios, T.; Kong, J.; Yang, H. Y. Functionalized MoS2 Nanosheet-Based Field-Effect Biosensor for Label-Free Sensitive Detection of Cancer Marker Proteins in Solution. Small 2014, 10, 1101−1105. (152) Su, S.; Chao, J.; Pan, D.; Wang, L.; Fan, C. Electrochemical Sensors Using Two-Dimensional Layered Nanomaterials. Electroanalysis 2015, 27, 1062−1072. (153) Kim, H.; Kim, H.; Ahn, C.; Kulkarni, A.; Jeon, M.; Yeom, G. Y.; Lee, M.; Kim, T. In situ Synthesis of Mos2 on a Polymer Based Gold Electrode Platform and Its Application in Electrochemical Biosensing. RSC Adv. 2015, 5, 10134−10138. (154) Wang, T.; Zhu, H.; Zhuo, J.; Zhu, Z.; Papakonstantinou, P.; Lubarsky, G.; Lin, J.; Li, M. Biosensor Based on Ultrasmall MoS2 Nanoparticles for Electrochemical Detection of H2O2 Released by Cells at the Nanomolar Level. Anal. Chem. 2013, 85, 10289−10295. (155) Wang, T.; Zhu, R.; Zhuo, J.; Zhu, Z.; Shao, Y.; Li, M. Direct Detection of DNA Below Ppb Level Based on Thionin-Functionalized Layered MoS2 Electrochemical Sensors. Anal. Chem. 2014, 86, 12064− 12069. (156) Su, S.; Sun, H.; Cao, W.; Chao, J.; Peng, H.; Zuo, X.; Yuwen, L.; Fan, C.; Wang, L. Dual-target electrochemical biosensing based on DNA structural switching on gold nanoparticle-decorated MoS2 nanosheets. ACS Appl. Mater. Interfaces 2016, 8, 6826−6833. (157) Li, X.; Shan, J.; Zhang, W.; Su, S.; Yuwen, L.; Wang, L. Recent Advances in Synthesis and Biomedical Applications of Two-Dimensional Transition Metal Dichalcogenide Nanosheets. Small 2017, 13, 1602660. (158) Hu, Y.; Huang, Y.; Tan, C.; Zhang, X.; Lu, Q.; Sindoro, M.; Huang, X.; Huang, W.; Wang, L.; Zhang, H. Two-dimensional transition metal dichalcogenide nanomaterials for biosensing applications. Mater. Chem. Frontiers 2017, 1, 24−36. (159) Li, B. L.; Wang, J.; Zou, H. L.; Garaj, S.; Lim, C. T.; Xie, J.; Li, N. B.; Leong, D. T. Low-Dimensional Transition Metal Dichalcogenide Nanostructures Based Sensors. Adv. Funct. Mater. 2016, 26, 7034−7056.

(123) Merki, D.; Fierro, S.; Vrubel, H.; Hu, X. L. Amorphous molybdenum sulfide films as catalysts for electrochemical hydrogen production in water. Chem. Sci. 2011, 2, 1262−1267. (124) Merki, D.; Vrubel, H.; Rovelli, L.; Fierro, S.; Hu, X. L. Fe, Co, and Ni ions promote the catalytic activity of amorphous molybdenum sulfide films for hydrogen evolution. Chem. Sci. 2012, 3, 2515−2525. (125) Benck, J. D.; Chen, Z.; Kuritzky, L. Y.; Forman, A. J.; Jaramillo, T. F. Amorphous Molybdenum Sulfide Catalysts for Electrochemical Hydrogen Evolution: Insights into the Origin of their Catalytic Activity. ACS Catal. 2012, 2, 1916−1923. (126) Huang, X.; Zeng, Z. Y.; Bao, S. Y.; Wang, M. F.; Qi, X. Y.; Fan, Z. X.; Zhang, H. Solution-phase epitaxial growth of noble metal nanostructures on dispersible single-layer molybdenum disulfide nanosheets. Nat. Commun. 2013, 4, 1444. (127) Lukowski, M. A.; Daniel, A. S.; Meng, F.; Forticaux, A.; Li, L.; Jin, S. Enhanced Hydrogen Evolution Catalysis from Chemically Exfoliated Metallic MoS2 Nanosheets. J. Am. Chem. Soc. 2013, 135, 10274−10277. (128) Voiry, D.; Yamaguchi, H.; Li, J.; Silva, R.; Alves, D. C. B.; Fujita, T.; Chen, M.; Asefa, T.; Shenoy, V. B.; Eda, G.; Chhowalla, M. Enhanced catalytic activity in strained chemically exfoliated WS2 nanosheets for hydrogen evolution. Nat. Mater. 2013, 12, 850−855. (129) Yu, Y.; Huang, S.; Li, Y.; Steinmann, S. N.; Yang, W.; Cao, L. Layer-dependent electrocatalysis of MoS2 for hydrogen evolution. Nano Lett. 2014, 14, 553−558. (130) Yin, W.; Yu, J.; Lv, F.; Yan, L.; Zheng, L. R.; Gu, Z.; Zhao, Y. Functionalized nano-MoS2 with peroxidase catalytic and near-infrared photothermal activities for safe and synergetic wound antibacterial applications. ACS Nano 2016, 10, 11000−11011. (131) Yu, X. Y.; Feng, Y.; Jeon, Y.; Guan, B.; Lou, X. W. D.; Paik, U. Formation of Ni−Co−MoS2 Nanoboxes with Enhanced Electrocatalytic Activity for Hydrogen Evolution. Adv. Mater. 2016, 28, 9006− 9011. (132) Yuan, X.; Li, X.; Zhang, X.; Li, Y.; Liu, L. MoS2 vertically grown on graphene with efficient electrocatalytic activity in Pt-free dyesensitized solar cells. J. Alloys Compd. 2018, 731, 685−692. (133) Xiao, D.; Liu, G. B.; Feng, W.; Xu, X. D.; Yao, W. Coupled spin and valley physics in monolayers of MoS2 and other group-VI dichalcogenides. Phys. Rev. Lett. 2012, 108, 196802. (134) Zhu, Z. Y.; Cheng, Y. C.; Schwingenschlogl, U. Giant spinorbit-induced spinsplitting in two-dimensional transition-metal dichalcogenide semiconductors. Phys. Rev. B: Condens. Matter Mater. Phys. 2011, 84, 153402. (135) Coehoorn, R.; Haas, C.; Dijkstra, J.; Flipse, C. J. F.; de Groot, R. A.; Wold, A. Electronic structure of MoSe2, MoS2, and WSe2. I. Band-Structure Calculations and Photoelectron Spectroscopy. Phys. Rev. B: Condens. Matter Mater. Phys. 1987, 35, 6195. (136) Coehoorn, R.; Haas, C.; de Groot, R. A. Electronic structure of MoSe2, MoS2, and WSe2. II. The Nature of the Optical Band Gaps. Phys. Rev. B: Condens. Matter Mater. Phys. 1987, 35, 6203. (137) Mak, K. F.; He, K.; Shan, J.; Heinz, T. F. Control of Valley Polarization in Monolayer MoS2 by Optical Helicity. Nat. Nanotechnol. 2012, 7, 494−498. (138) Splendiani, A.; Sun, L.; Zhang, Y.; Li, T.; Kim, J.; Chim, C. Y.; Galli, G.; Wang, F. Emerging Photoluminescence in Monolayer MoS2. Nano Lett. 2010, 10, 1271−1275. (139) Li, H.; Zhang, Q.; Yap, C. C. R.; Tay, B. K.; Edwin, T. H. T.; Olivier, A.; Baillargeat, D. From Bulk to Monolayer MoS2: Evolution of Raman Scattering. Adv. Funct. Mater. 2012, 22, 1385−1390. (140) Liu, H. L.; Shen, C. C.; Su, S. H.; Hsu, C. L.; Li, M. Y.; Li, L. J. Optical Properties of Monolayer Transition Metal Dichalcogenides Probed by Spectroscopic Ellipsometry. Appl. Phys. Lett. 2014, 105, 201905. (141) Eda, G.; Yamaguchi, H.; Voiry, D.; Fujita, T.; Chen, M.; Chhowalla, M. Photoluminescence from Chemically Exfoliated MoS2. Nano Lett. 2011, 11, 5111−5116. (142) Kumar, A.; Ahluwalia, P. K. Electronic structure of transition metal dichalcogenides monolayers 1H-MX2 (M = Mo, W; X = S, Se, 23


Review

ACS Applied Nano Materials (160) Chen, Y.; Wu, Y.; Sun, B.; Liu, S.; Liu, H. Two-Dimensional Nanomaterials for Cancer Nanotheranostics. Small 2017, 13, 1603446. (161) Mao, S.; Chang, J.; Pu, H.; Lu, G.; He, Q.; Zhang, H.; Chen, J. Two-dimensional nanomaterial-based field-effect transistors for chemical and biological sensing. Chem. Soc. Rev. 2017, 46, 6872−6904. (162) He, X. P.; Tian, H. Photoluminescence Architectures for Disease Diagnosis: From Graphene to Thin-Layer Transition Metal Dichalcogenides and Oxides. Small 2016, 12, 144−160. (163) Zhu, C.; Yang, G.; Li, H.; Du, D.; Lin, Y. Electrochemical Sensors and Biosensors Based on Nanomaterials and Nanostructures. Anal. Chem. 2015, 87, 230−249. (164) Narayanan, T. N.; Vusa, C. S. R.; Alwarappan, S. Selective and Efficient Electrochemical Biosensing of Ultrathin Molybdenum Disulfide Sheets. Nanotechnology 2014, 25, 335702. (165) Yang, T.; Chen, M.; Nan, F.; Chen, L.; Luo, X.; Jiao, K. Enhanced electropolymerization of poly(xanthurenic acid)−MoS 2 film for specific electrocatalytic detection of guanine and adenine. J. Mater. Chem. B 2015, 3, 4884−4891. (166) Yang, R.; Zhao, J.; Chen, M.; Yang, T.; Luo, S.; Jiao, K. Electrocatalytic determination of chloramphenicol based on molybdenum disulfide nanosheets and self-doped polyaniline. Talanta 2015, 131, 619−623. (167) Zhu, D.; Liu, W.; Zhao, D.; Hao, Q.; Li, J.; Huang, J.; Shi, J.; Chao, J.; Su, S.; Wang, L. Label-Free Electrochemical Sensing Platform for MicroRNA-21 Detection Using Thionine and Gold Nanoparticles Co-Functionalized MoS2 Nanosheet. ACS Appl. Mater. Interfaces 2017, 9, 35597−35603. (168) Yoon, J.; Lee, T.; Bapurao, B.; Jo, J.; Oh, B. K.; Choi, J. W. Electrochemical H2O2 Biosensor Composed of Myoglobin on MoS2 Nanoparticle-Graphene Oxide Hybrid Structure. Biosens. Bioelectron. 2017, 93, 14−20. (169) Su, S.; Sun, H.; Xu, F.; Yuwen, L.; Wang, L. Highly Sensitive and Selective Determination of Dopamine in The Presence Of Ascorbic Acid Using Gold Nanoparticles-Decorated Mos2 Nanosheets Modified Electrode. Electroanalysis 2013, 25, 2523−2529. (170) Yoon, J.; Lee, T.; Bapurao, B.; Jo, J.; Oh, B. K.; Choi, J. W. Electrochemical H2O2 Biosensor Composed of Myoglobin on MoS2 Nanoparticle-Graphene Oxide Hybrid Structure. Biosens. Bioelectron. 2017, 93, 14−20. (171) Wu, S.; Zeng, Z.; He, Q.; Wang, Z.; Wang, S. J.; Du, Y.; Yin, Z.; Sun, X.; Chen, W.; Zhang, H. Electrochemically Reduced Single-Layer MoS2 Nanosheets: Characterization, Properties, and Sensing Applications. Small 2012, 8, 2264−2270. (172) Su, S.; Sun, H.; Xu, F.; Yuwen, L.; Fan, C.; Wang, L. Direct Electrochemistry of Glucose Oxidase and a Biosensor for Glucose Based on A Glass Carbon Electrode Modified with MoS2 Nanosheets Decorated with Gold Nanoparticles. Microchim. Acta 2014, 181, 1497−1503. (173) Wang, Y.; Zhuang, Q.; Ni, Y. Fabrication of riboflavin electrochemical sensor based on homoadenine single-stranded DNA/ molybdenum disulfide−graphene nanocomposite modified gold electrode. J. Electroanal. Chem. 2015, 736, 47−54. (174) Yang, T.; Yang, R.; Chen, H.; Nan, F.; Ge, T.; Jiao, K. Electrocatalytic activity of molybdenum disulfide nanosheets enhanced by self-doped polyaniline for highly sensitive and synergistic determination of adenine and guanine. ACS Appl. Mater. Interfaces 2015, 7, 2867−2872. (175) Yang, T.; Chen, H.; Jing, C.; Luo, S.; Li, W.; Jiao, K. Using poly (m-aminobenzenesulfonic acid)-reduced MoS 2 nanocomposite synergistic electrocatalysis for determination of dopamine. Sens. Actuators, B 2017, 249, 451−457. (176) Geng, D.; Bo, X.; Guo, L. Ni-doped molybdenum disulfide nanoparticles anchored on reduced graphene oxide as novel electroactive material for a non-enzymatic glucose sensor. Sensor. Sens. Actuators, B 2017, 244, 131−141. (177) Parlak, O.; Iṅ cel, A.; Uzun, L.; Turner, A. P.; Tiwari, A. Structuring Au nanoparticles on two-dimensional MoS 2 nanosheets for electrochemical glucose biosensors. Biosens. Bioelectron. 2017, 89, 545−550.

(178) Matsumoto, A.; Miyahara, Y. Current and Emerging Challenges of Field Effect Transistor Based Bio-Sensing. Nanoscale 2013, 5, 10702−10718. (179) Nam, H.; Oh, B. R.; Chen, P.; Yoon, J. S.; Wi, S.; Chen, M.; Kurabayashi, K.; Liang, X. Two Different Device Physics Principles for Operating MoS2 Transistor Biosensors with Femtomolar-Level Detection Limits. Appl. Phys. Lett. 2015, 107, 012105. (180) Mak, K. F.; Lee, C.; Hone, J.; Shan, J.; Heinz, T. F. Atomically Thin MoS2: A new Direct-Gap Semiconductor. Phys. Rev. Lett. 2010, 105, 136805. (181) Di Bartolomeo, A. Graphene schottky diodes: An Experimental Review of The Rectifying Graphene/Semiconductor Heterojunction. Phys. Rep. 2016, 606, 1−58. (182) Deen, M. J.; Shinwari, M. W.; Ranuárez, J.; Landheer, D. Noise Considerations in Field-Effect Biosensors. J. Appl. Phys. 2006, 100, 074703. (183) Nam, H.; Oh, B. R.; Chen, P.; Chen, M.; Wi, S.; Wan, W.; Kurabayashi, K.; Liang, X. Multiple MoS2 Transistors for Sensing Molecule Interaction Kinetics. Sci. Rep. 2015, 5, 10546. (184) Sarkar, D.; Liu, W.; Xie, X.; Anselmo, A. C.; Mitragotri, S.; Banerjee, K. MoS2 Field-Effect Transistor for Next-Generation LabelFree Biosensors. ACS Nano 2014, 8, 3992−4003. (185) Lee, J.; Dak, P.; Lee, Y.; Park, H.; Choi, W.; Alam, M. A.; Kim, S. Two-dimensional layered MoS2 biosensors enable highly sensitive detection of biomolecules. Sci. Rep. 2015, 4, 7352. (186) Lim, D.; Kannan, E. S.; Lee, I.; Rathi, S.; Li, L.; Lee, Y.; Khan, M. A.; Kang, M.; Park, J.; Kim, G. H. High performance MoS2-Based Field-Effect Transistor Enabled by Hydrazine Doping. Nanotechnology 2016, 27, 225201. (187) Yang, Y.; Yang, X.; Tan, Y.; Yuan, Q. Recent Progress in Flexible and Wearable Bio-Electronics Based on Nanomaterials. Nano Res. 2017, 10, 1560−1583. (188) Viswanathan, S.; Narayanan, T. N.; Aran, K.; Fink, D.; Paredes, J.; Ajayan, P. M.; Filipek, S.; Miszta, P.; Tekin, H. C.; Inci, F.; Demirci, U.; Li, P.; Bolotin, K. I.; Liepmann, D.; Renugopalakrishanan, V. Graphene-Protein Field Effect Biosensors: Glucose Sensing. Mater. Today 2015, 18, 513−522. (189) Baek, S. H.; Choi, Y.; Choi, W. Large-Area Growth of Uniform Single-Layer MoS2 Thin Films by Chemical Vapor Deposition. Nanoscale Res. Lett. 2015, 10, 388. (190) Zhao, W.; Yu, H.; Liao, M.; Zhang, L.; Zou, S.; Yu, H.; He, C.; Zhang, J.; Zhang, G.; Lin, X. Large Area Growth of Monolayer MoS2 Film on Quartz and its Use as a Saturable Absorber in Laser ModeLocking. Semicond. Sci. Technol. 2017, 32, 025013. (191) Bersch, B. M.; Eichfeld, S. M.; Lin, Y. C.; Zhang, K.; Bhimanapati, G. R.; Piasecki, A. F.; Labella, M., III; Robinson, J. A. Selective-area growth and controlled substrate coupling of transition metal dichalcogenides. 2D Mater. 2017, 4, 025083. (192) Hussain, S.; Shehzad, M. A.; Vikraman, D.; Khan, M. F.; Singh, J.; Choi, D. C.; Seo, Y.; Eom, J.; Lee, W. G.; Jung, J. Synthesis and Characterization of Large-Area and Continuous MoS2 Atomic Layers by RF Magnetron Sputtering. Nanoscale 2016, 8, 4340−4347. (193) Su, Y.; Kshirsagar, C. U.; Robbins, M. C.; Haratipour, N.; Koester, S. J. Symmetric Complementary Logic Inverter Using Integrated Black Phosphorus and MoS2 Transistors. 2D Mater. 2016, 3, 011006. (194) Kwon, H.; Jeon, P. J.; Kim, J. S.; Kim, T. Y.; Yun, H.; Lee, S. W.; Lee, T.; Im, S. Large Scale MoS2 Nanosheet Logic Circuits Integrated by Photolithography on Glass. 2D Mater. 2016, 3, 044001. (195) Wang, H.; Yu, L.; Lee, Y. H.; Shi, Y.; Hsu, A.; Chin, M. L.; Li, L. J.; Dubey, M.; Kong, J.; Palacios, T. Integrated Circuits Based on Bilayer MoS2 Transistors. Nano Lett. 2012, 12, 4674−4680. (196) Lee, D. W.; Lee, J.; Sohn, I. Y.; Kim, B. Y.; Son, Y. M.; Bark, H.; Jung, J.; Choi, M.; Kim, T. H.; Lee, C.; Lee, N. E. Field-Effect Transistor with a Chemically Synthesized MoS2 Sensing Channel for Label-Free and Highly Sensitive Electrical Detection of DNA Hybridization. Nano Res. 2015, 8, 2340−2350. (197) de Moraes, A. C. M.; Kubota, L. T. Recent Trends in FieldEffect Transistors-Based Immunosensors. Chemosensors 2016, 4, 20. 24


Review


Oligonucleotides Induced Dispersion Behavior for Label-Free Detection of Single-Nucleotide Polymorphism. Adv. Funct. Mater. 2015, 25, 3541−3550.

(198) Naylor, C. H.; Kybert, N. J.; Schneier, C.; Xi, J.; Romero, G.; Saven, J. G.; Liu, R.; Johnson, A. T. C. Scalable Production of Molybdenum Disulfide Based Biosensors. ACS Nano 2016, 10, 6173− 6179. (199) Zhu, C.; Zeng, Z.; Li, H.; Li, F.; Fan, C.; Zhang, H. Single-layer MoS2-based Nanoprobes for Homogeneous Detection of Biomolecules. J. Am. Chem. Soc. 2013, 135, 5998−6001. (200) Huang, Y.; Shi, Y.; Yang, H. Y.; Ai, Y. A Novel Single-Layered MoS2 Nanosheet Based Microfluidic Biosensor for Ultrasensitive Detection of DNA. Nanoscale 2015, 7, 2245−2249. (201) Singh, P.; Gupta, R.; Sinha, M.; Kumar, R.; Bhalla, V. MoS2 based Digital Response Platform for Aptamer Based Fluorescent Detection of Pathogens. Microchim. Acta 2016, 183, 1501−1506. (202) Kong, R. M.; Ding, L.; Wang, Z.; You, J.; Qu, F. A Novel Aptamer-Functionalized MoS2 Nanosheet Fluorescent Biosensor for Sensitive Detection of Prostate Specific Antigen. Anal. Bioanal. Chem. 2015, 407, 369−377. (203) Xiang, X.; Shi, J.; Huang, F.; Zheng, M.; Deng, Q.; Xu, J. MoS2 Nanosheet-Based Fluorescent Biosensor for Protein Detection via Terminal Protection of Small-Molecule-Linked DNA and Exonuclease III-Aided DNA Recycling Amplification. Biosens. Bioelectron. 2015, 74, 227−232. (204) Huang, J.; Ye, L.; Gao, X.; Li, H.; Xu, J.; Li, Z. Molybdenum Disulfide-Based Amplified Fluorescence DNA Detection Using Hybridization Chain Reactions. J. Mater. Chem. B 2015, 3, 2395−2401. (205) Zhang, N.; Ma, W.; Han, D.; Wang, L.; Wu, T.; Niu, I. The Fluorescence Detection of Glutathione by •OH Radicals’ Elimination with Catalyst Of Mos2/Rgo under Full Spectrum Visible Light Irradiation. Talanta 2015, 144, 551−558. (206) Wang, Y.; Hu, J.; Zhuang, Q.; Ni, Y. Label-Free Fluorescence Sensing of Lead (II) Ions and Sulfide Ions Based on Luminescent Molybdenum Disulfide Nanosheets. ACS Sustainable Chem. Eng. 2016, 4, 2535−2541. (207) Yang, Y.; Liu, T.; Cheng, L.; Song, G.; Liu, Z.; Chen, M. MoS2based Nanoprobes for Detection of Silver ions in Aqueous Solutions and Bacteria. ACS Appl. Mater. Interfaces 2015, 7, 7526−7533. (208) Liu, X.; Li, L.; Wei, Y.; Zheng, Y.; Xiao, Q.; Feng, B. Facile Synthesis of Boron-and Nitride-Doped MoS 2 Nanosheets as Fluorescent Probes for the Ultrafast, Sensitive, and Label-Free Detection of Hg2+. Analyst 2015, 140, 4654−4661. (209) Jin, K.; Xie, L.; Tian, Y.; Liu, D. Au-Modified Monolayer MoS2 Sensor for DNA Detection. J. Phys. Chem. C 2016, 120, 11204−11209. (210) Han, J.; Xia, H.; Wu, Y.; Kong, S. N.; Deivasigamani, A.; Xu, R.; Hui, K. M.; Kang, Y. Single-layer MoS2 Nanosheet Grafted Upconversion Nanoparticles for Near-Infrared Fluorescence ImagingGuided Deep Tissue Cancer Phototherapy. Nanoscale 2016, 8, 7861− 7865. (211) Wang, J.; Tan, X.; Pang, X.; Liu, L.; Tan, F.; Li, N. MoS2 Quantum Dot@Polyaniline Inorganic−Organic Nanohybrids for in vivo Dual-Modal Imaging Guided Synergistic Photothermal/Radiation Therapy. ACS Appl. Mater. Interfaces 2016, 8, 24331−24338. (212) Liu, B.; Li, C.; Chen, G.; Liu, B.; Deng, X.; Wei, Y.; Xia, J.; Xing, B.; Ma, P.; Lin, J. Synthesis and Optimization of MoS2@ Fe3O4ICG/Pt (IV) Nanoflowers for MR/IR/PA Bioimaging and Combined PTT/PDT/Chemotherapy Triggered by 808 nm Laser. Adv. Sci. 2017, 4, 1600540. (213) Wang, Y.; Hu, J.; Zhuang, Q.; Ni, Y. Enhancing sensitivity and selectivity in a label-free colorimetric sensor for detection of iron (II) ions with luminescent molybdenum disulfidenanosheet-based peroxidase mimetics. Biosens. Bioelectron. 2016, 80, 111−117. (214) Guo, X.; Wang, Y.; Wu, F.; Ni, Y.; Kokot, S. A colorimetric method of analysis for trace amounts of hydrogen peroxide with the use of the nano-properties of molybdenum disulfide. Analyst 2015, 140, 1119−1126. (215) Lin, T.; Zhong, L.; Guo, L.; Fu, F.; Chen, G. Seeing diabetes: visual detection of glucose based on the intrinsic peroxidase-like activity of MoS2 nanosheets. Nanoscale 2014, 6, 11856−11862. (216) Li, B. L.; Zou, H. L.; Lu, L.; Yang, Y.; Lei, J. L.; Luo, H. Q.; Li, N. B. Size-Dependent Optical Absorption of Layered MoS2 and DNA 25
