Disposable electrochemical enzyme-amplified genosensor for Salmonella bacteria detection

This paper describes the use of oligonucleotide modified screen-printed carbon electrodes for the enzyme-amplified sensing of DNA sequences that identify the Salmonella bacteria. The capture probe was immobilized onto screen-printed carbon electrodes using the adsorption method. Hybridization reaction was detected through the sandwich format, based on the coupling of biotin-streptavidin interaction using a streptavidin conjugated to alkaline phosphatase. The enzyme catalyzed the conversion of electroinactive alpha-naphthyl phosphate to alpha-naphthol; this product is electroactive and has been detected by differential pulse voltammetry. The electrochemical genoassay allowed specific detection of the polymerase chain reaction (PCR) amplified targets, even diluting the sample of interest about 50-fold.