Nanotechnology Nanotechnology 26 (2015) 115102 (13pp)
Nanocluster of superparamagnetic iron oxide nanoparticles coated with poly (dopamine) for magnetic ﬁeld-targeting, highly sensitive MRI and photothermal cancer therapy Ming Wu1,2, Da Zhang1,2, Yongyi Zeng1,2,3, Lingjie Wu1,2, Xiaolong Liu1,2 and Jingfeng Liu1,2,3 1
The United Innovation of Mengchao Hepatobiliary Technology Key Laboratory of Fujian Province, Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou 350025, People’s Republic of China 2 The Liver Center of Fujian Province, Fujian Medical University, Fuzhou 350025, People’s Republic of China 3 Liver Disease Center, The First Afﬁliated Hospital of Fujian Medical University, Fuzhou 350005, People’s Republic of China E-mail: [email protected]
and [email protected]
Received 14 November 2014, revised 28 January 2015 Accepted for publication 9 February 2015 Published 27 February 2015 Abstract
In this paper, a core–shell nanocomposite of clusters of superparamagnetic iron oxide nanoparticles coated with poly(dopamine) (SPION [email protected]
) is fabricated as a magnetic ﬁeld-directed theranostic agent that combines the capabilities of highly sensitive magnetic resonance imaging (MRI) and photothermal cancer therapy. The highly concentrated SPION cluster core is suitable for sensitive MRI due to its superparamagnetic properties, and the poly (dopamine) coating layer can induce cancer cell death under near-infrared (NIR) laser irradiation because of the photothermal conversion ability of PDA. MRI scanning reveals that the nanocomposite has relatively high r2 and r2* relaxivities, and the r2* values are nearly threefold higher than the r2 values because of the clustering of the SPIONs in the nanocomposite core. Due to the rapid response to magnetic ﬁeld gradients, enhanced cellular uptake of our nanocomposite mediated by an external magnetic ﬁeld can be achieved, thus producing signiﬁcantly enhanced local photothermal killing efﬁciency against cancer cells under NIR irritation. S Online supplementary data available from stacks.iop.org/NANO/26/115102/mmedia Keywords: superparamagnetic iron oxide nanoparticles cluster coated with poly(dopamine), magnetic ﬁeld-targeting, MRI, photothermal (Some ﬁgures may appear in colour only in the online journal) 1. Introduction
Superparamagnetic iron oxide nanoparticles (SPIONs), a T2 contrast agent in MRI, have been widely used in detecting disease, injuries, or deﬁciencies in the liver, spleen, and lymph nodes and have demonstrated great potential for application with respect to the early diagnosis of cancer [4–7].
Magnetic resonance imaging (MRI) is a noninvasive imaging modality that provides images with excellent spatial resolution via a precisely tuned radio frequency wave [1–3]. 0957-4484/15/115102+13$33.00
© 2015 IOP Publishing Ltd Printed in the UK
Nanotechnology 26 (2015) 115102
M Wu et al
was reported that PDA may be used as a novel photothermal therapy (PTT) agent due to its high photothermal conversion efﬁciency under near-infrared (NIR) irradiation . Yang et al have reported a multifunctional [email protected]
core–shell nanocomposite for imaging-guided photothermal therapy for cancer , but it suffers from low MRI relaxivities and low magnetic ﬁeld response because of a single SPION core in its structure. Here we have gone a step further and have fabricated an SPION [email protected]
core–shell nanocomposite as a magnetic ﬁeld–directed cancer theranostic agent that combines highly sensitive MRI capability due to the extremely high relaxation rates of the SPION cluster core and cancer cell killing capability due to the photothermal conversion effect of the poly(dopamine) coating layer under near-infrared (NIR) laser irradiation.
However, even with the contrast enhancement of SPIONs, MRI still suffers from low sensitivity. Because most commonly commercialized SPIONs, such as dextran-coated Endorem and carboxydextran-coated Resovist, are ultrasmall (