Design and Functionalization of the NIR-Responsive Photothermal Semiconductor Nanomaterials for Cancer Theranostics

Abstract

Despite the development of medical technology, cancer still remains a great threat to the survival of people all over the world. Photothermal therapy (PTT) is a minimally invasive method for selective photothermal ablation of cancer cells without damages to normal cells. Recently, copper chalcogenide semiconductors have emerged as a promising photothermal agent attributed to strong absorbance in the near-infrared (NIR) region and high photothermal conversion efficiency. An earlier study witnessed a rapid increase in their development for cancer therapy, including CuS, CuSe and CuTe nanocrystals. However, a barrier is that the minimum laser power intensity for effective PTT is still significantly higher than the conservative limit for human skin exposure. Improving the photothermal conversion efficiency and reducing the laser power density has become a direction for the development of PTT. Furthermore, in an effort to improve the therapeutic efficacy, many multimode therapeutic nanostuctures have been formulated by integrating the photothermal agents with antitumor drugs, photosensitizers, or radiosensitizers, resulting in a synergistic effect. Various functional materials also have been absorbed, attached, encapsulated, or coated on the photothermal nanostructures, including fluorescence, computed tomography, magnetic resonance imaging, realizing cancer diagnosis, tumor location, site-specific therapy, and evaluation of therapeutic responses via incorporation of diagnosis and treatment. In this Account, we present an overview of the NIR-responsive photothermal semiconductor nanomaterials for cancer theranostics with a focus on their design and functionalization based on our own work. Our group has developed a series of chalcogenides with greatly improved NIR photoabsorption as photothermal agents, allowing laser exposure within regulatory limits. We also investigated the photothermal bioapplications of hypotoxic oxides including WO, MoO, and RuO, expanding their applications into a new field of photothermal materials. Furthermore, considering a much more enhanced therapeutic effect of multifunctional nanoagents, our group elaborately designed many nanocomposites, such as core-shell nanoparticles of FeO@CuS and CuS@mSiO, based on the integration of photothermal agents with contrast agents or other anticancer medicines, achieving cancer theranostic and synergistic treatment. Ternary compound nanocrystals were also prepared with synthetic simplicity for multimodal imaging-guided therapy for cancer. This Account summarizes our past work, including the design and concept, synthesis, and characterization for in vitro and in vivo applications. Then, we analyzed the tendencies of the NIR-responsive photothermal semiconductor nanomaterials for clinical applications, highlighting their prospects and challenges. We believe that the photothermal technology from the NIR-responsive photothermal semiconductor nanomaterials would promote cancer theranostics to result in giant strides forward in the future.

Hydrogels for Medical and Environmental Applications

“…An injectable, shear‐thinning (thixotropic), gold nanorod‐incorporated, poly (N‐isopropylacrylamide‐co‐methacrylated poly‐β‐cyclodextrin (pNIPAm‐co‐MPCD)‐based hydrogel was shown to be used as a long‐acting implant (20 d stability noted via in vivo studies in mice) for chemo‐photothermal cancer therapy . Photothermal therapy (PTT) is a minimally invasive technique to specifically destroy/ablate cancer cells, preventing healthy cells from significant damage . They use photothermal agents which can absorb light energy and convert it to heat at the specific tumor sites, which can destroy cancer cells via thermal ablation (>45 ° C) or hyperthermia (40–45 °C) .…”

A Multifunctional Biodegradable Nanocomposite for Cancer Theranostics

“…Sci. [7,10,12,18] After 24 h, the mice were euthanized and ex vivo fluorescence imaging was performed on the major organs (heart, liver, spleen, lung, and kidney) and tumor tissue (Figure 6g). The area under the curve (AUC) of ICG/PFP@HMOP-PEG was distinctly greater than the AUC for the other two formulations (Table S1, Supporting Information).…”

“…Various theranostic materials have been explored for tumor imaging and treatment. [7][8][9] The latter are similar to mesoporous silicas, but rather than comprising pure SiO 2 contain organic functional groups within the silica framework. [6] A wide range of organic and inorganic nanomaterial-based theranostic systems have been explored, including mesoporous organosilica nanoparticles (MONs).…”

“…[20,21] A number of contrast agents comprising gasfilled microbubbles can be used for US imaging. [7] PA imaging can improve both the resolution and depth of the US approach. [22] Since micrometer-sized bubbles cannot enter a tumor, they need to be generated in situ, and enhancement of bubble stability would also be highly beneficial for monitoring treatment.…”

Radionuclide 188Re‐Loaded Photothermal Hydrogel for Cancer Theranostics

“…Due to the high specificity, noninvasiveness, low toxicity to normal tissues, photothermal therapy (PTT) employing generated heat from the absorbed optical energy to ablate cancer has attracted attention as an alternative to traditional cancer treatment . Various inorganic phototherapeutic materials including gold nanomaterials and carbon nanomaterials, with strong transformation from near‐infrared (NIR) laser light into thermal energy, have shown encouraging therapeutic efficacy in preclinical animal experiments .…”