A radiation toxicity biosensing platform based on radioresistant bacteria modified with dr_0423

Radiation toxicity is important for evaluating potential health risks associated with radioactive substances or environmental radioactivity. Whole-cell biosensors can be applied to quantify radiation toxicity, yet it is technically challenging to identify a radiation-sensitive gene in a radioresistant strain and to maintain an ideal microenvironment for the promising radiation toxicity measurement. Herein, we report a microfluidic radiation toxicity whole-cell biosensing scheme based on a transgenic bacteria, membrane microfabrication, dielectrophoresis (DEP)-based cell trapping and amperometric detection. We have identified a radiation-responsive gene promoter (dr_0423) unique to the radioresistant strain D. radiodurans, leading to the development of transgenic bacteria DRPZ423. The dr_0423 promoter activates the expression of beta-galactosidase upon DNA damage from ionizing irradiation, which catalyzes the conversion of p-aminophenyl beta-D-galacto-pyranoside (PAPG) to p-aminophenol (PAP), and generates electrons for amperometric detection. Our biosensing scheme was validated using X-ray and alpha particles, showing promising results with a relative standard deviation of 2.78–6.38 % and a recovery rate exceeding 93.3 %. This biosensing platform offers a reliable method for measuring radiation toxicity, suitable for various applications such as environmental hazard assessment and beyond.