Gold nanoparticle‐mediated photothermal therapy: applications and opportunities for multimodal cancer treatment

Abstract

Photothermal therapy (PTT), in which nanoparticles embedded within tumors generate heat in response to exogenously applied laser light, has been well documented as an independent strategy for highly selective cancer treatment. Gold-based nanoparticles are the main mediators of PTT because they offer: (1) biocompatibility, (2) small diameters that enable tumor penetration upon systemic delivery, (3) simple gold-thiol bioconjugation chemistry for the attachment of desired molecules, (4) efficient light-to-heat conversion, and (5) the ability to be tuned to absorb near-infrared light, which penetrates tissue more deeply than other wavelengths of light. In addition to acting as a standalone therapy, gold nanoparticle-mediated PTT has recently been evaluated in combination with other therapies, such as chemotherapy, gene regulation, and immunotherapy, for enhanced anti-tumor effects. When delivered independently, the therapeutic success of molecular agents is hindered by premature degradation, insufficient tumor delivery, and off-target toxicity. PTT can overcome these limitations by enhancing tumor- or cell-specific delivery of these agents or by sensitizing cancer cells to these additional therapies. All together, these benefits can enhance the therapeutic success of both PTT and the secondary treatment while lowering the required doses of the individual agents, leading to fewer off-target effects. Given the benefits of combining gold nanoparticle-mediated PTT with other treatment strategies, many exciting opportunities for multimodal cancer treatment are emerging that will ultimately lead to improved patient outcomes.

Antimicrobial Nanoparticles: applications and mechanisms of action

“…However, photo thermal therapy (PTT) offers a promising new approach for improving the bactericidal potential of AuNPs. 28 Gold nanoparticles irradiated with laser energy release heat due to the excitation and oscillation of electrons, making them useful as anticancer or antibacterial agents. AuNPs treated S. aureus had enhanced bactericidal effect when exposed to laser energy.…”

“…AuNPs treated S. aureus had enhanced bactericidal effect when exposed to laser energy. 28 Gold nanoparticles have been studied as potential drug and gene delivery systems in cancer therapy.…”

Gold nanoparticles enlighten the future of cancer theranostics

“…86,[125][126][127][128][129] Two main processes occur based on the heat energy contents: 1) the heat from the energy transformation is passed to the surrounding medium via the phonon-phonon relaxation within ~100 ps and 2) a competitive process takes place between the heating by the electrons and the cooling by the surrounding medium, and when the heating rate is much faster than the cooling rate, AuNPs are melted in hundreds of femtoseconds. [125][126][127][128] To facilitate cancer PTT, the first process has to dominate, and therefore, continuous-wave (CW) lasers that overlap maximally with the AuNP SPR absorption band need to be utilized.…”

Multimodal Magnetic-Plasmonic Nanoparticles for Biomedical Applications

“…An external NIR laser can be applied, causing the oscillation of the plasmons and resulting in the nanoparticles generating heat, which has been shown to be highly effective in the thermal ablation of cancer cells [61,62]. Nanoparticles based on gold are the most popular choice for photothermal agents as it is biocompatible enabling a thiol functionalisation which allows the easy attachment of antibodies and other targeting agents.…”