Electrochemical Detection of Gene of Based on Glucose-Oxidase-Mimicking Nanotags of Gold-Nanoparticles-Doped Copper Metal-organic Frameworks.

The present work developed an electrochemical genosensor for the detection of virulence outer membrane protein A ( tDNA) gene of () by exploiting the excellent glucose-oxidase-mimicking activity of copper Metal-organic frameworks (Cu-MOF) doped with gold nanoparticle (AuNPs). The signal nanotags of signal probes (sDNA) that biofunctionalized AuNPs@Cu-MOF (sDNA-AuNPs@Cu-MOF) were designed using an Au-S bond. The biosensor was prepared by immobilization capture probes (cDNA) onto an electrodeposited AuNPs-modified glassy carbon electrode (GCE). AuNPs@Cu-MOF was introduced onto the surface of the GCE via a hybridization reaction between cDNA and tDNA, as well as tDNA and sDNA. Due to the enhanced oxidase-mimicking activity of AuNPs@Cu-MOF to glucose, the biosensor gave a linear range of 1.0 × 10 to 1.0 × 10 mol L to tDNA with a detection limit (LOD) of 0.42 fmol L under optimized conditions using differential pulse voltammetry measurement (DPV). It can be applied in the direct detection of gene segments in total DNA extracts from with a broad linear range of 5.4-5.4 × 10 CFU mL and a LOD of 0.35 CFU mL. The biosensor showed good selectivity, fabricating reproducibility and storage stability, and can be used for the detection of gene segments in real samples with recovery between 87.5% and 107.3%.