A capacitive DNA sensor-based test for simple and sensitive analysis of antibiotic resistance in field setting

To meet urgent needs for solving serious worldwide drug-resistance problems, a sensitive label-free capacitive sensor developed in our group was investigated as a tool to be applied in the field of antibiotic resistance genotyping, for instance the detection of ampicillin resistance gene (ampR). Proof-of-concept data demonstrated its detection sensitivity of pico-molar without any signal amplification step and a dynamic range of at least three orders of magnitude. The detection limits of less than 1 pM for the single-stranded ampR oligonucleotide and 4 pM for the double-stranded target can reliably be achieved after only 2.5 min sample reaction. Reusability of the probe-functionalized disposable electrode was investigated by comparing different regeneration solutions; mix of 25 mM NaOH/30% formamide was employed to regenerate the electrode for at least six cycles without significant loss of sensing ability. Assay is performed automatically and result is retrieved in 20 min. The developed sensitive genotyping tool is expected to provide simple, fast and affordable screening for monitoring spread of antibiotic resistances, which is suitable for testing in field setting.