Detection of hexahydro-1,3-5-trinitro-1,3,5-triazine (RDX) with a microbial sensor

Explosives such as hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) are common contaminants found in soil and groundwater at military facilities worldwide, but large-scale monitoring of these contaminants at low concentrations is difficult. Biosensors that incorporate aptamers with high affinity and specificity for a target are a novel way of detecting these compounds. This work describes novel riboswitch-based biosensors for detecting RDX. The performance of the RDX riboswitch was characterized in Escherichia coli using a range of RDX concentrations from 0-44 μmol l^-1. Fluorescence was induced at RDX concentrations as low as 0.44 μmol l^-1. The presence of 4.4 μmol l^-1 RDX induced an 8-fold increase in fluorescence and higher concentrations did not induce a statistically significant increase in response.