Photothermal Therapy for Cancer Treatment

Abstract

Photothermal therapyPhotothermal Therapy is a technique which utilizes light-absorbing materials and converts light energy into heat energy to damage tumor cells. In particular, near-infraredNear Infrared region starts from 800 to 2500 nm is used to induce cell death through photothermal effect. To achieve efficient heat production at tumor site this therapy is facilitated by near-infraredNear Infrared absorbents such as gold, copper sulfide, copper selenide, carbon nanotubes, nanographenes, and dyes like indocyanine green. Generally, fluence rateFluence rate and irradiation timeIrradiation time are mainly two key parameters that influence the anti-tumor activity through photothermal effect. But sometimes it is impossible to determine the true information about the tumor size and the effective distribution of near-infraredNear Infrared absorbents as a consequence therapeutic effect of photothermal therapyPhotothermal Therapy remains noneffective. Another important consideration in photothermal therapyPhotothermal Therapy is heating tumor tissue at optimized temperatureTemperature and minimizing the collateral damage to normal tissues that surrounds the tumor tissue. Commonly tumor tissue is heated to a temperatureTemperature of 50 °C or above to induce inflammation, necrosis, and ultimately cause thermal damage. Moreover, biocompatibility with biological tissue and biopersistence of near-infraredNear Infrared absorbents are also important to treat cancerCancer. Most of the inorganic materials used as photothermal agentsPhotothermal agents remain in the body for a longer period of time therefore eventually organic conductive materials like porphysome, polypyrrole, etc., have recently triggered extensive attention because of their biodegradable nature. However, considering the wavelengthWavelength of laser light for exciting photothermal absorbersPhotothermal absorbers also contributes as a promising candidate to ensure deep tissue penetration of heat. Amalgamating with nano drug delivery technology these organic materials cause better penetration into the tissues and tumor-homing ability which further ensures accurate laser exposure and superior tumor ablation. Despite of aforementioned challenges and important critical considerations with photothermal therapyPhotothermal Therapy it has emerged as an attractive non-invasive technique for tumor ablation.