Measurement of alpha radiation based on amperometric activity of bacteria focused electrokinectically in microfluidics

The nuclear radiation exposure in Fukushima in 2011 has aroused the publics' anxiety on nuclear safety. The alpha particles in such radiation may induce cancer and other serious diseases once entering the human body, yet high-sensitivity detection of alpha radiation remains unavailable and technically challenging. Here, we report the development of an effective and reliable alpha radiation measurement scheme requiring an exposure area of <1 cm2 based on microfluidics. The working principle is based on the β-galactosidase generation of genetically modified radiation-resistant bacteria Deinococcus Radiodurans upon exposure of alpha radiation. We further adopt dielectrophoretic focusing to increase the local population density of D. Radiodurans in the exposure region in the device. P-Aminophenyl-β-D-galacto-pyranoside (PAPG) will be added to the detection chamber in order to convert β-galactosidase to p-Aminophenol (PAP), which can then be quantified by amperometry through electrochemical sensing electrodes prefabricated inside the detection chamber. Therefore, the microfluidic radiation sensor can quantify the alpha radiation level as electrical signals. As a pilot study, we first apply isopropyl β-D-1-Thiogalactopyranoside (IPTG) to induce an equivalent effect as the radiation exposure for calibrating the microfluidic detection scheme. We will present our results on the measurement of alpha radiation in our conference presentation. Altogether, this work has demonstrated a novel biomicrofluidic technique for achieving effective and reliable radiation monitoring with reduced cost.