Multifunctional Inorganic Nanoparticles: Recent Progress in Thermal Therapy and Imaging

Abstract

Nanotechnology has enabled the development of many alternative anti-cancer approaches, such as thermal therapies, which cause minimal damage to healthy cells. Current challenges in cancer treatment are the identification of the diseased area and its efficient treatment without generating many side effects. Image-guided therapies can be a useful tool to diagnose and treat the diseased tissue and they offer therapy and imaging using a single nanostructure. The present review mainly focuses on recent advances in the field of thermal therapy and imaging integrated with multifunctional inorganic nanoparticles. The main heating sources for heat-induced therapies are the surface plasmon resonance (SPR) in the near infrared region and alternating magnetic fields (AMFs). The different families of inorganic nanoparticles employed for SPR- and AMF-based thermal therapies and imaging are described. Furthermore, inorganic nanomaterials developed for multimodal therapies with different and multi-imaging modalities are presented in detail. Finally, relevant clinical perspectives and the future scope of inorganic nanoparticles in image-guided therapies are discussed.

Keywords: alternate magnetic field; image-guided therapy; imaging; inorganic nanoparticles; photothermal therapy; surface plasmon resonance.

Figure 1

Scheme illustrating the potential of inorganic nanoparticles in heat-induced therapies and imaging. US: ultrasound; MR: magnetic resonance; CT: computed tomography; QD: quantum dot; UCNP: upconversion nanoparticles; CuS: copper sulfide; CNT: carbon nanotube; AMF: alternate magnetic field; ROS: reactive oxygen species.

Figure 2

In vitro and in vivo micro-CT images: (A) concentration-dependent CT images of air, distilled water, and doxorubicin-loaded hollow gold nanoparticles (Dox-HGNPs); (B) X-ray absorption of Dox-HGNP and Ultravist 300; (C) cross-sectional CT image in the back skin of mice after injection of Dox-HGNPs; and (D) Ultravist 300. Reproduced with permission from [51]. Copyright Journal of Controlled Release, Elsevier, 2015.

Figure 3

In vivo multispectral optoacoustic tomography (MSOT) imaging. (a–e) MSOT images of tumor before and after intravenous injection with Bi₂S₃ nanorods (NRs); and (f) photoacoustic signal intensity in tumor at different time points. Reproduced with permission from [105]. Copyright American Chemical Society, 2015.

Figure 4

(A) Thermal images acquired after the intratumoral injection of nanocubes and the application of magnetic hyperthermia (MHT), near-infrared (NIR)-laser irradiation, or dual-mode treatment (both effects); (B) thermal elevation curves for the non-injected tumor in the dual condition; (C) average final temperature increase obtained on day 0 (1h after injection) and one and two days after injection for non-injected tumors; and (D) average tumor growth in nanocube-injected mice. Reproduced with permission from [143]. Copyright American Chemical Society, 2015.

Figure 5

Multimodal in vivo imaging of quantum rattles (QRs): (A) NIR fluorescent intensity in the areas where QRs (red) and non-fluorescent hollow mesoporous silica shells (HS) control (blue); (B) MR image obtained following the injection of QRs; and 3D photoacoustic images of tumors acquired at 670 nm before (C) and after (D) the injection of QRs. Reproduced with permission from [191]. Copyright Proceedings of the National Academy of Sciences of the United States of America, 2015.