Genotoxicity monitoring using a 2D-spectroscopic GFP whole cell biosensing system

A 2D-spectroscopic genotoxicity biosensing system is presented. This optical sensing system monitors the genotoxicant-induced expression of green fluorescent protein (GFP) in a recombinant Escherichia coli strain. In this organism, GFP synthesis is driven by the recA gene promoter of the bacterial SOS DNA repair system. Using nalidixic acid as a model genotoxicant, we have demonstrated a response range that varies as a function of the excitation wavelength. When GFP fluorescence was monitored at 510 nm, the linear working range to nalidixic acid was within the range of 0.03–0.3 ppm at 390 nm excitation and 0.05–0.3 ppm at 480 nm excitation.