Rapid and Sensitive Strategy for Salmonella Detection Using an InvA Gene-Based Electrochemical DNA Sensor

摘要

A rapid and sensitive strategy for the detection of Salmonella was proposed by integrating simpleDNA extraction, specific polymerase chain reaction (PCR) with an invA gene-based electrochemicalDNA sensor. The amplified target sequence of invA gene could be specifically captured on the sensinginterface, and further hybridized with biotinylated detection probe to form a sandwich-typehybridization structure. The electrochemical signal was amplified by streptavidin-alkaline phosphatase(ST-AP), producing sensitive enzyme-catalyzed electrochemical DNA sensing. The fabrication andhybridization processes were characterized with electrochemical impedance spectroscopy (EIS), squarewave voltammetry (SWV) and surface plasmon resonance (SPR). The designed DNA sensor coulddiscriminate satisfactorily the complementary and mismatched oligonucleotides, indicating goodselectivity. The linear calibration range for target DNA detection was from 1 pM to 10 nM with adetection limit of 0.5 pM, showing high sensitivity. Under optimal conditions, the proposed strategy5 -1 could quantitatively detect Salmonella from 10 to 10 CFU mL within 3.5 h. This strategy presented asimple, rapid and sensitive platform for Salmonella detection and would become a powerful tool forpathogenic microorganisms screening in clinical diagnostics, food safety, biothreat detection andenvironmental monitoring.