Determination of topographical radiation dose profiles using gel nanosensors

Abstract

Despite the emergence of sophisticated technologies in treatment planning and administration, routine determination of delivered radiation doses remains a challenge due to limitations associated with conventional dosimeters. Here, we describe a gel-based nanosensor for the colorimetric detection and quantification of topographical radiation dose profiles in radiotherapy. Exposure to ionizing radiation results in the conversion of gold ions in the gel to gold nanoparticles, which render a visual change in color in the gel due to their plasmonic properties. The intensity of color formed in the gel was used as a quantitative reporter of ionizing radiation. The gel nanosensor was used to detect complex topographical dose patterns including those administered to an anthropomorphic phantom and live canine patients undergoing clinical radiotherapy. The ease of fabrication, operation, rapid readout, colorimetric detection, and relatively low cost illustrate the translational potential of this technology for topographical dose mapping in radiotherapy applications in the clinic.

Radiation-Responsive Amino Acid Nanosensor Gel (RANG) for Radiotherapy Monitoring and Trauma Care

“…We also previously used a similar approach for the spatial determination of ionizing radiation doses. 28 Addition of 700 μL of 5 mM glutathione, a thiol-containing tripeptide, indeed arrested the development of color in the hydrogel, lending further credence to this hypothesis (Figure 4C). Taken together, these results indicate the need for chloroaurate ions, phenylalanine, tryptophan, and glutathione as functional components for detecting ionizing radiation; as indicated previously, interaction with the phenyl ring in phenylalanine likely inhibits spontaneous nanoparticle formation in the presence of tryptophan.…”

“…Glutathione from MilliporeSigma (700 μL of 5 mM) was added on top of the RANG 10 min postirradiation and incubated for 30 min in order to was arrest growth of nanoparticles in the irradiated RANGs. 28 Glutathione on the surface was discarded after incubation, and the RANGs were washed with Milli-Q water to further remove any excess glutathione. The samples were transported back (driving time ≈ 30 min) to Arizona State University for subsequent analyses.…”

“…Gold nanoparticles demonstrate unique size- and shape-dependent plasmonic properties, which have been exploited in several biomedical applications. , We recently developed a sensing approach in which templating ligands (e.g., cationic surfactants) facilitate the formation of gold nanoparticles from colorless precursor salt solutions following exposure to therapeutic levels of radiation. − Here, we carried out fundamental studies on the templating of gold nanoparticles by amino acids and related compounds under ionizing radiation. Parallel screening, chemical informatics modeling, foundational mechanistic studies, and translational evaluation were carried out, and lead candidates were formulated as radiation-responsive amino acid nanosensor gels or RANGs for use in dose detection applications.…”

Fluorescent Nanogel Sensors for X-ray Dosimetry

“…Excessive or insufficient doses of X-rays potentially threaten patients, so monitoring the delivered doses is of vital significance. To reach this goal, a variety of sensors (or dosimeters) have been developed to measure the dose of ionizing radiation. − For instance, thermoluminescent dosimeters are widely used for personal dosimetry. The pretreatment and readout procedure of thermoluminescent dosimeters are complicated and time-consuming .…”

“…Hydrogels feature three-dimensional polymeric networks with a large amount of water, showing good tissue equivalence. Hydrogels have garnered much attention for a variety of sensors, biosensors, and X-ray dosimeters. ,− Ionizing radiation-induced polymerization hydrogel-based dosimeters are widely studied; however, polymerization continues up to 48 h after irradiation. Therefore, they cannot be utilized immediately after irradiation .…”