Analysis of the Efficiency of Photothermal and Photodynamic Cancer Therapy via Nanogolds and Photosensitizers

Abstract

Factors influencing the cancer therapy efficiency in both photothermal therapy (PTT) and photodynamic therapy (PDT) using nanogold particles and photosensitizers, respectively, are analyzed. In PTT, heat diffusion kinetics is used to calculate the temperature increase resulted from the nanogold absorption of light energy, whereas photochemical kinetics is used to find the efficacy of PDT, or the generation rate of reactive oxygen species. The critical factors of the PTT/PDT synergistic efficacy include: the concentration of the initiator (nanogold or photosensitizers) in the treated medium, the wavelength and energy of the light applied to the medium. Optimal parameters are calculated for maximum PDT efficacy. In PTT, diode laser (at 810 nm) is used to heat nanogolds (rod-shape or core-shell). In PDT, photosensitizers of riboflavin, 5-ALA, methylene blue and indocyanine green may be used with the associate light at wavelength of (365, 430 nm), (530-670 nm) and (780-850 nm) respectively. Both single light or dual light in infrared or visible wavelength are proposed to activate the photosensitizers or nanogolds. Optimization is required for maximum synergistic efficacy.