Functional fullerene-molybdenum disulfide fabricated electrochemical DNA biosensor for Sul1 detection using enzyme-assisted target recycling and a new signal marker for cascade amplification

Abstract This work describes a DNA biosensor for sensitive detection of the specific Sul1 gene of Salmonella typhimurium. First of all, polyamidoamine (PAMAM) functionalized fullerene (C60) and molybdenum disulfide (MoS2) nanohybrid is synthesized and employed as sensing platform. Secondly, MoS2 doped polyaniline (PANI) nanocomposite is designed as redox nanoprobe to enhance electrochemical signal. Moreover, exonuclease III (exo III)-assisted target recycling strategy impels a large amount of single-stranded capture probe to hybridize with signal marker, resulting in a significantly enhanced response signal. With the cascade amplification strategy, the proposed biosensor shows high sensitivity for target DNA detection with a wide detection linear range from 40 fM to 40 nM. More importantly, it has been applied for assay of Sul1 from Salmonella typhimurium with high specificity and sensitivity, which provides a methodological guidance for detection of pathogenic bacteria.