Gravure Printed Electrochemical Biosensor - Science Direct

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Procedia Engineering 25 (2011) 956 – 959

Proc. Eurosensors XXV, September 4-7, 2011, Athens, Greece

Gravure Printed Electrochemical Biosensor A.S.G. Reddya*, B.B. Narakathua, M.Z. Atashbara,b, M. Rebrosb, E. Rebrosovab, M.K. Joyceb a

Depatment of Electrical and Computer engineering, Western Michigan University,Kalamazoo, 49008, USA. b Center for Advancement of Printed Electronics, Western Michigan University,Kalamazoo, 49008, USA.

Abstract An impedance based electrochemical biosensor was successfully printed using a rotogravure printing technique. The biosensor was fabricated on a flexible poly ethylene terephthalate (PET) substrate and silver (Ag) nano particle based ink was used as metallization for the printed interdigitated electrodes ,'(¶V , with dimensions of 200 μm width and spacing. The response of the printed device towards different bio/chemical species such as cadmium sulphide (CdS), lead sulphide (PbS), D-proline and mouse IgG were measured using electrochemical impedance spectroscopy (EIS). The response of the printed biosensors towards these bio/chemicals demonstrated detection capabilities as low as picomolar levels.

© 2011 Published by Elsevier Ltd. Open access under CC BY-NC-ND license. Keywords: Electrochemical; impedance; biosensor; gravure printing; printed electronics; printed sensor.

1. Introduction In recent years, a lot of interest has been centered on the development of low cost printed electronic devices on flexible substrates. Due to the advantages of printing techniques such as high throughput, minimal usage of resources, lower manufacturing temperatures and cost efficiency, research has focused on the use of traditional printing methods such as screen, ink-jet, gravure, flexography and offset [1±4] for manufacturing electronic devices. Research has shown the development of printed electronics for applications such as SULQWHG VHQVRUV >@ UDGLR IUHTXHQF\ LGHQWLILFDWLRQ WDJV 5),'¶V >@ UROOXS displays [3] and RUJDQLFWKLQILOPWUDQVLVWRUV27)7¶V >4]. However, there are no studies that report on

* Corresponding author. Tel.: +1-269-779-8030; fax: +1-269-276-3151. E-mail address: [email protected].

1877-7058 © 2011 Published by Elsevier Ltd. Open access under CC BY-NC-ND license. doi:10.1016/j.proeng.2011.12.235

A.S.G. Reddy et al. / Procedia Engineering 25 (2011) 956 – 959

the adaption of continuous and large area roll-to-roll (R2R) printing methods for the development of electrochemical biosensors. The development of reliable, miniaturized, accurate and cost effective electrochemical sensors that detects various biochemicals is essential for the agricultural, environmental and medical industries [5-6]. The use of interdigitated electrodes (IDEs) for electrochemical biosensing with miniaturized size has also been demonstrated in many studies [7]. Research by Tabei et.al. has showed that microelectrodes provide a higher sensitivity and better signal to noise ratio then macroelectrodes [8]. Traditional immunoassay techniques such as radio immunoassay (RIA), enzyme linked immune assay (ELISA) and fluoro immunoassay (FIA) are hazardous, expensive, laborious and require specific labels for biochemical detection purposes, thus making them more complex and time consuming [9]. Electrochemical impedance spectroscopy (EIS) provides high sensitivity and has received tremendous attention in the field of electrochemical biosensor development [10]. In this work, the use of rotogravure printing for the fabrication of an efficient electrochemical biosensor that incorporates silver (Ag) IDEs is demonstrated. The IDEs, with electrode finger dimensions of 200 μm width and spacing, were rotogravure printed on a flexible poly ethylene terephthalate (PET) substrate. The capability of the fabricated device was demonstrated through the detection of different biochemical species such as cadmium sulfide (CdS), lead sulfide (PbS), D-proline and mouse IgG. 2. Experimental A 175 μm thick PET (Melinex ST 506) from DuPont Teijin Films was used as substrate. IDEs were gravure printed using Ag nanoparticle based ink (TEC-PR-20) from Inktec Inc., with an average particle size of 20 to 30 nm. CdS, PbS, phosphate buffer saline (PBS) (all in crystalline form) and D-proline (in liquid form) were purchased from Sigma±Aldrich Chemical Company. Mouse monoclonal IgG antibody was purchased from Bio-Design International Inc. A PBS (pH 7.4) solution was formed by dissolving crystalline PBS in DI water. Various concentrations of D-proline (100 pM, 100 nM and100 μM) and Mouse IgG (10 pM, 10 nM and 10 μM) were prepared by mixing with PBS. CdS and PbS were dissolved in DI water to prepare different concentrations (100 pM, 100 nM and 100 μM). The electrochemical biosensor was fabricated at the WMU Printing Pilot Plant with Western Michigan 8QLYHUVLW\¶VZHE-fed Cerutti Gravure Press which is known for its high quality printing, high print speeds and use of low viscosity inks. The conductive silver nanoparticle based ink, was used for the metallization of the microelectrodes. The printed device comprises of 8 pair of electrodes; each electrode has dimensions of 8600 ȝPOHQJWK ȝPZLGWKDQG ȝPHOHFWURGHVSDFLQJ (Fig. 1(a)). An array of the printed impedance based biosensors on flexible PET substrates is shown in Fig. 1(b). All measurements were conducted at room temperature. First, the biosensor was rinsed with isopropyl alcohol and distilled water and dried in pressurized air. Varying concentrations of 100 μl sample solutions of PbS, CdS, D-Proline, and Mouse IgG were loaded onto the printed biosensor. The response of the fabricated device at an applied potential of 100 mV and an operating frequency range of 1 Hz to 1 MHz

(a) Fig. 1. (a) Single and (b) array of rotogravure printed electrochemical biosensors.

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was observed. EIS on the printed biosensor was performed using a PARSTAT 2273 potentiostat which was connected to the printed device using alligator clips. The PARSTAT 2273 was controlled by a PC via USB, using a custom-built LabVIEW program. Calibration for the probes and wires was done before taking measurements. At the end of each experiment, the biosensor was rinsed with distilled water and dried with pressurized air. 3. Results and Discussion Fig. 2 depicts the response of the biosensor towards CdS (Fig. 2 (a)) and PbS (Fig. 2 (b)), which are highly toxic pollutants in land and water, for 10 Hz and 100 Hz at an applied potential of 100 mV. The impedance response of the printed biosensor towards CdS was demonstrated in an impedance change from 1.04 0 WR 0.85 0 to 0.8 0; and for PbS from 0 WR 0 WR 0 as the concentration was varied from 100 pm to 100 nM to100 μM, respectively at an operating frequency of 10 Hz. CdS and PbS were detected at concentrations as low as 100 pM which is well below the limit of 3 μM and 3 mM for CdS and PbS regulated by USFDA [11]. Figure 3 (a) depicts the response of the biosensor towards D-proline; which is structurally similar to domoic acid that is a main cause of seafood poisoning. In this figure, the three sets of bars represent the percentage change in measured impedances for the 100 pM, 100 nM and 100μM concentrations of D-proline at operating frequencies of 100 Hz, 200 Hz, 700 Hz and 1 kHz, when compared to the base solution of PBS. It can be observed that the change in impedance percentage value increases as the concentration of the solution was increased. As an example, for measurements at 1 kHz frequency, the impedance percentage change value increased from 45 % to 55 % to 60 % as the concentration of Dproline increased from 100 pM to 100 nM to 100 μM, respectively when compared to PBS. D-proline was detected as low as 100 pM while the USFDA limits for domoic acid is 20 μM [12].

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Fig. 2. Impedance response of printed sensors towards (a) CdS and (b) PbS; at applied potential of 100 mV

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Fig. 3. Impedance response of printed sensors towards (a) D-Proline and (b) Mouse IgG; at applied potential of 100 mV.


Fig. 3(b) depicts the measured impedances for 10 pM, 10 nM and 10 μM concentrations of mouse IgG at an operating frequency range of 1 Hz to 1 MHz and an applied potential of 100 mV. It was observed that a better signal to noise ratio was achieved at lower frequencies of 10 Hz to 2 kHz (as shown in the inset of Fig. 3(b)). As an example, for the measurements at 100 Hz frequency, the impedance value changed by 2 %, 3 % and 5 %, when compared to PBS levels, for 10 pM, 10 nM and 10 μM concentrations of mouse IgG. 4. Conclusion An electrochemical biosensor was successfully inkjet printed using a Ag nanoparticle based ink, with electrodes dimensions of 200 μm (width and spacing). The impedance based response of the sensor towards toxic heavy metals like CdS and PbS, and biological proteins such as D±proline and mouse IgG showed a percentage change of 70 %, 45 %, 60 % and 5 % when compared to DI and PBS, respectively at an applied potential of 100 mV. The results obtained show a promising potential for printed electrochemical biosensors to distinguish among the pico, nano and micro level concentrations of various bio/chemical species. Future studies include research to fabricate selective printed bio/chemical sensors, which can be integrated into Lab-on-a-Chip (LOC) sensing systems. Acknowledgement This work has been partially supported by the U.S Army Grant No. W911NF-09-C-0135. References [1] Reddy ASG, Narakathu BB, Atashbar MZ, Rebros M, Rebrosova E, Joyce M, et al. Printed Capacitive Based Humidity Sensors on Flexible Substrates. Sens. Lett. 2011;9:869-71. [2]. Nilsson HE, Siden J, Olsson T, Jonsson P. Koptioug A. Evaluation of a printed patch antenna for robust microwave RFID tags. IET Microw. Antennas Propag. 2007;1:776±81. [3] Mach P, Rodriguez SJ, Nortrup R, Wiltzius P, Rogers JA. Monolithically integrated, flexible display of polymer-dispersed liquid crystal driven by rubber-stamped organic thin-film transistors. Appl. Phys. Lett. 2001;78:3592±94. [4] Yamao T, Juri K, Kamoi A Hottaa S. Field-effect transistors based on organic single crystals grown by an improved vapor phase method. org. electron. 2009;10:1241-47. [5] Narakathu BB, Bejcek BE, Atashbar MZ. Improved detection limits of toxic biochemical species based on impedance measurements in electrochemical biosensors. Biosensors and Bioelectronics 2010;26:923±8. [6] Petrlova J, Potesil D, Zehnalek J, Sures B, Adam V, et.al. Cisplatin electrochemical biosensor. Electrochim. Acta. 2006;51:5169-73. [7] Liu Q, Yu J, Xiao L, Tang JCO, Zhang Y, Wang P, Yang M. Impedance studies of bio-behavior and chemosensitivity of cancer cells by micro-electrode arrays. Biosens. Bioelectron. 2008;24:1305-10. [8] Tabei H, Takahashi M, Hoshino S, Niwa O, Horiuchi T. Subfemtomole detection of catecholamine with interdigitated array carbon microelectrodes in HPLC. Anal.Chem. 1994;66:3500-02. [9] Muramatsu H, Dicks JM, Tamiya E, Karube I. Piezoelectric crystal biosensor modified with Protein-A for determinationa of Immunoglobins. Anal. Chem. 1987;59:2760-63. [10] Schoning MJ, Krause R, Block K, Musahmeh M, Mulchandani A, Wang J. A dual amperometric/potentiometric FIA-based biosensor for the distinctive detection of organophosporus pesticides. Sens. Actuat. B: Chem. 2003;95:291±96. [11] Sheets RW. Extraction of lead, cadmium and zinc from overglaze decorations on ceramic dinnerware by acidic and basic food substances. Sci. of the total environ. 1997; 197:167-75. [12] Lefebvre KA, Silver MW, Coale SL, Tjeerdema RS. Domoic acid in planktivorous fish in relation to toxic Pseudonitzschia cell densities. Mar.Biol. 2002;140:625-31.

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