Enhanced Sensitivity and Responses to Viologens from a Whole Cell Bacterial Bioreporter Treated with Branched Polyethyleneimines

Aims Evaluate the use of polyethyleneimines (PEIs) as membrane permeabilizers to improve the responses and sensitivity of a bacterial bioreporter strain to viologens. Methods and Results The responses from E. coli str. EBS, i.e., E. coli BW25113 carrying plasmid pSDS, when exposed to five different viologens was characterized, as were the toxicities of seven different PEIS, including two linear and five branched species. Based upon these results, benzyl viologen led to the greatest responses and 0.8 kDa branched PEI (BPEI) was the least toxic of the PEIs tested and, therefore, both were selected for the subsequent tests. The bioluminescence and relative responses from E. coli str. EBS exposed to various concentrations of 0.8 kDa BPEI identified 400 mg L−1 as the optimal concentration. Using this concentration, tests were performed with all five of the viologens. Conclusions The responses from E. coli str. EBS to the viologens were improved, with the maximum relative bioluminescence values increasing between 5.6 and 16.5-fold. The minimum detectable levels for four of the viologens were likewise improved 2- to 4-fold. This article is protected by copyright. All rights reserved.