Understanding the Role of NIR Laser Power and Wavelength in Tuning the Photothermal Transduction Efficiency of Gold Nanosystems in Biomedical Applications

Photothermal therapy (PTT) is an emerging, affordable alternative to conventional therapies for superficial tumors and topical microbial infections. Photothermal agents (PTA) play a crucial role to achieve PTT. Several nanoparticles have been widely used as PTA owing to their small size and tunability of absorbance in the near infrared region (NIR). When irradiated with the NIR laser, they generate localized heat, which results in localized ablation of cancer cells or microbes. Additionally, several organic or inorganic PTAs exhibit surface plasmon resonance (SPR), an important characteristic for achieving laser-induced hyperthermia. However, among the various nano PTAs, the metallic nanosystems exhibit comparatively better thermal raise properties. Among the metallic systems, gold is a superior, biocompatible, and well-studied system for PTT. However, the photothermal conversion efficacy of the PTAs greatly depend on the wavelength and the power of the laser source used. In this regard, this study is aimed at understanding the photothermal conversion efficacy of gold coated calcium peroxide nanoparticles when exposed to lasers of various wavelengths and power. The results showed that the photothermal conversion efficacy (PTE) of the particles irradiated with continuos laser was higher, when compared with the particles irradiated with low power pointer laser and pulsed laser.