DNA biosensor for detection of Neisseria gonorrhoeae causing sexually transmitted disease.

A sequence-specific electrochemical sexually transmitted disease (STD) sensor based on self-assembled monolayer of thiolated DNA probe specific to target opa gene for detection of Gonorrhoea, a sexually transmitted disease has been fabricated. 6-Mercapto-1-hexanol (MCH) has been used as a blocking agent to facilitate oligos "stand" up at the surface, a configuration favoring subsequent DNA hybridization and to repel non-specific adsorption of undesired DNA. The results of differential pulse voltammetric studies of this STD sensor reveal low detection limit (1.0 × 10(-18)M) and a wide dynamic range (from 1.0 × 10(-6)M to 0.5 × 10(-18)M) arising due to the stable hybridization using methylene blue as an electro-active DNA hybridization indicator. The experimental results with genomic DNA, clinical patient sample of Neisseria gonorrhoeae, culture of non-N. gonorrhoeae Neisseria species (NgNS) and gram negative bacteria indicate that the fabricated sensor is specific to this STD.