Nano-Au/cMWCNT Modified speB Gene Specific Amperometric Sensor for Rapidly Detecting Streptococcus pyogenes causing...

A specific 5' NH₂ labeled DNA probe of speB gene was immobilized onto the gold nanoparticles/carboxylated multi walled carbon nanotubes (Nano-Au/cMWCNT) screen printed electrode using EDC/NHS cross linking chemistry. This was followed by hybridization with 0.5-50 ng/6 µl of single stranded genomic DNA Streptococcus pyogenes infected patient throat swab samples. Electrochemical amperometric assay was deciphered by using cyclic voltammetry (CV) with methylene blue a redox indicator. The sensor had a sensitivity of 104.7 µA cm^-2 ng^-1 using CV with a R² of 0.907 and 0.01 ng/6 µl as the limit of detection (LOD). The modified electrode surface morphology was characterized using scanning electron microscopy. The stability of the electrode was seen at 4 °C for 180 days having 6% loss in the initial current. The sensor is speB gene specific and can detect the pathogen within 30 min.