Plasmonic Gel Based Nanosensor for Colorimetric Dose Response in Proton Beam Therapy

Proton beam therapy is a state of the art radiotherapy medical procedure that uses proton beams for tumor ablation for cancer treatment. One of the major advantages of proton therapy over traditional particle therapy methods is that the exit dose for protons is negligible as compared to other charged particles reducing the damage caused to healthy tissue. This study reports the development of a novel plasmonic gel based nanosensor for colorimetric dose response in the therapeutic dose range (0.5-5 Gy) implemented in proton beam therapy. Gold salt present in the gel undergo reduction from Au⁺ to Au(0) to eventually form gold nanoparticles templated by cationic surfactants following irradiation with proton beams. A resulting pink colored gel is formed with different intensities quantifying the different radiation doses employed during the study. The chain length of the cationic surfactants was varied and its role in determining nanoparticle formation efficacy was determined. A linear range for detection from 0-3 Gy signifies its application in fractionated radiotherapy. A successful test of translational capability of the gel based nanosensor was displayed when it was able to detect the delivered the dose delivered to the anthropomorphic phantom. The simplicity in fabrication of these gels, its detection range for radiotherapy regime and the ease in colorimetric detection with translational potentials represents the first of its kind gel based plasmonic nanosensor for clinical proton beam therapy.