Novel approach for rapid electrochemical profiling of Escherichia coli cell-free supernatant

Herein, we present a novel approach for the characterization of Escherichia coli cell-free supernatant (CFS), based on sample preparation with microfluidic superheating technology and electrodetection of total amount of low molecular weight compounds. CFS pretreatment through an innovative microfluidic superheating enabled removal of extracellular vesicles primary masking the oxidation of electroactive metabolites at screen-printed electrodes. After vesicles removal, the electrooxidation of low molecular weight compounds formed in CFSs as a result of bacterial activity became possible. Our protocol showed low intra-day deviation for CFSs after superheating and high run-to-run electric signal reproducibility and can provide quantitative information on the total content of electroactive compounds. This study represents a significant advance in our comprehension of E. coli CFSs as a source of electroactive low molecular weight compounds and their in vitro profiling by means of electrochemical techniques.