Nanoclay gel-based radio-fluorogenic gel dosimeters using various fluorescence probes

We report a nanoclay-based radio-fluorogenic gel (NC-RFG) dosimeters using various fluorescence probes, including coumarin, coumarin-3-carboxylic acid (CCA), benzoic acid, terephthalic acid, trimeric acid, and pyromellitic acid. Following irradiation, these non-fluorescent compounds were converted into fluorescent compounds via interaction with OH radicals produced by water radiolysis. The dose responses of the respective NC-RFGs under X-ray irradiation were evaluated using a fluorescent spectrometer and, with the exception of the coumarin sample, were found to demonstrate high linearity within the range 0-5 Gy. Using the CCA-based fluorescence probe, the effects of preparation condition were investigated and comparisons of its gelatin-based gel and aqueous solutions were made. The high sensitivity of the CCA-based NC-RFG was found to arise from enhancement effects dependent on nanogel gel characteristics such as pH and low reactivity via radicals.