Novel Gram-negative bacteria hydrogel radiation dosimeters: Water equivalence and comparison with Gram-positive bacterial dosimeter

Hydrogel-based dosimeters incorporating microbiological agents have emerged as promising tools for assessing radiation effects in biologically relevant environments. In this study, the water equivalence of hydrogels inoculated with Escherichia coli (Gram-negative) is evaluated and compared with systems containing Staphylococcus aureus (Gram-positive). Analytical methods and Monte Carlo simulations were employed to determine mass stopping power and attenuation coefficients for electrons, protons, and photons. The results demonstrate strong agreement between E. coli and S. aureus-based systems, with differences below 4 % for mass stopping power and 2 % for attenuation coefficients. These findings indicate that Gram-negative inoculated hydrogels exhibit near water-equivalent behavior across clinically relevant radiation types. Overall, it is found that E. coli-based hydrogel dosimeters show significant potential for application in therapeutic beam dosimetry, while also providing a platform for investigating radiation-induced biological effects.