Biological Applications of Thermoplasmonics

Abstract

Thermoplasmonics has emerged as an extraordinarily versatile tool with profound applications across various biological domains ranging from medical science to cell biology and biophysics. The key feature of nanoscale plasmonic heating involves remote activation of heating by applying laser irradiation to plasmonic nanostructures that are designed to optimally convert light into heat. This unique capability paves the way for a diverse array of applications, facilitating the exploration of critical biological processes such as cell differentiation, repair, signaling, and protein functionality, and the advancement of biosensing techniques. Of particular significance is the rapid heat cycling that can be achieved through thermoplasmonics, which has ushered in remarkable technical innovations such as accelerated amplification of DNA through quantitative reverse transcription polymerase chain reaction. Finally, medical applications of photothermal therapy have recently completed clinical trials with remarkable results in prostate cancer, which will inevitably lead to the implementation of photothermal therapy for a number of diseases in the future. Within this review, we offer a survey of the latest advancements in the burgeoning field of thermoplasmonics, with a keen emphasis on its transformative applications within the realm of biosciences.

Scattering/Fluorescence Dual-Mode Imaging in MnO2-Coated Silicon Nanospheres for Cancer Cell Detection

“…Nanoparticles (NPs) exhibiting light scattering, fluorescence, photothermal effects, etc., have been developed as imaging and sensing nanoprobes for cancer diagnosis, , photothermal therapy (PTT), , photodynamic therapy (PDT), , and chemodynamic therapy (CDT). , In these techniques, the tumor microenvironment (TME), which is a complex microenvironment created by various cells, such as immune system and vascular system cells, along with cancer cells and tumors, is an important target for diagnosis and for ascertaining therapeutic efficacy. − TME is often characterized by acidic pH levels, overexpression of glutathione (GSH), and high hydrogen peroxide (H 2 O 2 ) levels. , Gold (Au) or silver (Ag) NPs have been used as a main constituent of TME-responsive optical nanoprobes because of their excellent photophysical properties such as large scattering and absorption cross sections and the capability of fluorescence enhancement due to localized surface plasmon resonances (LSPR). ,− Scattering/fluorescence GSH and H 2 O 2 imaging/detection nanoprobes have been developed from plasmonic Ag and Ag 2 S NPs covered with fluorophores by the formation of a GSH and H 2 O 2 -reactive shell such as a manganese oxide (MnO 2 ) shell. ,,,,− Dissolution of the shell via a redox reaction with GSH and H 2 O 2 changes the dielectric environment of NPs, causing the shift of the LSPR peak, which can be monitored as the change of the dark-field (DF) scattering color, , fluorescence intensity, ,, magnetic resonance (MR) signals, , surface-enhanced Raman scattering signals, etc. In addition, the release of Mn 2+ as a reaction product of MnO 2 and GSH serves as an agent to initiate CDT .…”