A Colorimetric Plasmonic Nanosensor for Dosimetry of Therapeutic Levels of Ionizing Radiation

Abstract

Modern radiation therapy using highly automated linear accelerators is a complex process that maximizes doses to tumors and minimizes incident dose to normal tissues. Dosimeters can help determine the radiation dose delivered to target diseased tissue while minimizing damage to surrounding healthy tissue. However, existing dosimeters can be complex to fabricate, expensive, and cumbersome to operate. Here, we demonstrate studies of a liquid phase, visually evaluated plasmonic nanosensor that detects radiation doses commonly employed in fractionated radiotherapy (1-10 Gy) for tumor ablation. We accomplished this by employing ionizing radiation, in concert with templating lipid surfactant micelles, in order to convert colorless salt solutions of univalent gold ions (Au(1)) to maroon-colored dispersions of plasmonic gold nanoparticles. Differences in color intensities of nanoparticle dispersions were employed as quantitative indicators of the radiation dose. The nanoparticles thus formed were characterized using UV-vis absorbance spectroscopy, dynamic light scattering, and transmission electron microscopy. The role of lipid surfactants on nanoparticle formation was investigated by varying the chain lengths while maintaining the same headgroup and counterion; the effect of surfactant concentration on detection efficacy was also investigated. The plasmonic nanosensor was able to detect doses as low as 0.5 Gy and demonstrated a linear detection range of 0.5-2 Gy or 5-37 Gy depending on the concentration of the lipid surfactant employed. The plasmonic nanosensor was also able to detect radiation levels in anthropomorphic prostate phantoms when administered together with endorectal balloons, indicating its potential utility as a dosimeter in fractionated radiotherapy for prostate cancer. Taken together, our results indicate that this simple visible nanosensor has strong potential to be used as a dosimeter for validating delivered radiation doses in fractionated radiotherapies in a variety of clinical settings.

Protein‐facilitated gold nanoparticle formation as indicators of ionizing radiation

“…Therefore, there is a need to independently verify the radiation dose delivered to the patient to ensure patient safety and improve the quality of life posttreatment. (Pushpavanam, Narayanan, Chang, Sapareto, & Rege, ). Facile radiation sensors that are easy to fabricate, operate and read would enable clinicians and physicists to verify the radiation dose independently and assist in decision making for future irradiations administered to the patient; however, current dosimeters are insufficient for many routine clinical applications due to their inherent limitations.…”

“…Recently, a gold‐alanine nanocomposite has been evaluated as a radiation dosimeter but the requirement of a sophisticated readout technique like electron paramagnetic resonance has prevented its clinical translation (Guidelli, Ramos, Zaniquelli, Nicolucci, & Baffa, ). To mitigate these concerns, a colorimetric sensor based on the formation of gold nanoparticles as a response to therapeutic levels of ionizing radiation was demonstrated (Sahil Inamdar et al, ; Pushpavanam et al, ). The intensity of color was proportional to the intensity of irradiation and was used as a measure of ionizing radiation.…”

MiRNA Extraction from Cell-Free Biofluid Using Protein Corona Formed around Carboxyl Magnetic Nanoparticles

“…Nanotechnology is holding great promise for diseases diagnosis, targeted delivery of drugs, and biosensors 15–17 . Recently, it has been demonstrated that proteins bind to the surface of nanoparticles when nanomaterials are introduced to biological fluids, to form clouds of adsorbed proteins known as ‘protein corona’ 18–19 .…”

Application of nanotechnology to cancer radiotherapy

“…The detection range can also be expanded to 5–37 Gy through modulating the concentration and chemistry of the templating liquid surfactant. With the help of this nanosensor, the qualitative detection of radiation can be observed by naked eye, and the quantitative radiation dose can be analyzed by an absorbance spectrophotometer (Pushpavanam et al 2015). …”