Dose enhancement factor caused by gold nanoparticles: influence of the dosimetric sensitivity and radiation dose assessed by electron spin resonance dosimetry

Abstract

Gold nanoparticles have been extensively used to increase the sensitivity of radiation dosimeters. In this work, nanocomposites of alanine (Ala), 2-methylalanine (2MA), asparagine (Asn) and monosodium glutamate (MSG) containing gold nanoparticles were prepared. The influence of the mass percentage of gold (0.1% up to 3%), absorbed dose (2 Gy–10 kGy) and the intrinsic sensitivity of these materials on the dose enhancement factor (DEF) were investigated. The prepared nanocomposites were characterized by UV–vis absorption spectroscopy and dynamic light scattering technique. Electron spin resonance spectroscopy was employed to assess the dosimetric response. The results revealed that the gold nanoparticles aggregated in the nanocomposites of MSG and Asn but not in the Ala and 2MA samples. Higher DEFs were observed for materials with lower intrinsic sensitivities (Asn and MSG) and for lower doses of radiation, suggesting that the dosimetric response of the nanocomposite dosimeters is governed by the probability of radical recombination. The higher the radiation dose, gold mass percentage and/or intrinsic sensitivity of the dosimetric material, the higher the production of radiation-induced free-radicals, enhancing the probability of radical recombination and resulting in lower DEFs. These results bring new insights about the use of gold nanoparticles to the construction of more sensitive radiation dosimeters.

Review of nanomaterial advances for ionizing radiation dosimetry

“…Recently, nanocomposites of alanine (Ala), 2-methylalanine (2MA), asparagine (Asn) and monosodium glutamate (MSG) with various mass % of AuNPs from 0.1 to 3% were compared for dosimetric applications. 128 Additionally, the influence of intrinsic sensitivity of these materials and the absorbed dose (2 Gy–10 kGy) and on DEFs were investigated. The findings showed that the AuNP aggregated in the irradiated MSG and Asn molecules but did not in the Ala or 2MA nanocomposites.…”

Assessment of dosimetric sensitivity enhancement of xylenol orange Fricke gel by AuNPs: optical and MR imaging investigation

“…To this end, 200 mL of 2 mmol l −1 aqueous chloroauric acid solution was added to 200 mL of 8 mmol l −1 aqueous sodium borohydride solution. The system was kept under strong agitation at room temperature for 12 h (Guidelli et al 2016, Lima et al 2021. The initial solution changed its color from yellow to red, indicating that a colloidal dispersion was formed.…”

“…Inserting metallic nanoparticles such as gold and silver nanoparticles (AuNPs and AgNPs, respectively) into dosimetric gels has successfully enhanced their dosimetric sensitivity as verified by Electron Paramagnetic Resonance (EPR, via the EPR-Alanine system) and Optically Stimulated Luminescence (OSL) emission, thereby favoring applications at low-energy photon dosimetry (Guidelli et al 2012, Guidelli et al 2016, Lima et al 2021. The increased sensitivity observed in the case of the EPR-Alanine system stems from the high atomic number of the metallic nanoparticles.…”

Chemical Overview of Gel Dosimetry Systems: A Comprehensive Review

“…It was assumed that the lower DEF of 100 nm AuNPs in comparison with 50 nm particles could be due to the self-absorption effect with larger diameters. Lima et al [ 150 ] established that the higher the radiation dose, gold mass percentage, and/or intrinsic sensitivity of the dosimetry material, the higher the production of radiation-induced free-radicals, enhancing the probability of radical recombination and resulting in lower DEF values.…”