Design, fabrication and testing of an electrochemically based DNA biosensor for detection of Coniella Granati fungal disease of pomegranate fruit and aster yellows bacterial grapevine disease

[摘要] ENGLISH ABSTRACT: A portable low cost electrochemical DNA potentiostat biosensor was investigatedfor the detection of Coniella granati pathogenic disease of pomegranate fruit, using linear biotinylated DNA probes, immobilized on streptavidin modified screen printed carbon electrode.A cyclic voltammetric based electrochemical technique was chosen to detect the presence of Coniella granati pathogenic disease. A modified streptavidin screen printed carbon electrode was selected as a transducer, with the biotinylatedprobe DNA immobilized non-covalently on the electrode workspace. The streptavidin-biotinylated probe DNA was validated by the use of streptavidin coated magnetic beads, with the biotinylated probe DNA in a bind or washbuffer solution.A portable electrochemical potentiostat was designed and fabricated to electronicallydetect the change in current peak due to the electrochemical reductionand oxidation reaction of the DNA samples, after the immobilization occurred. A potassium ferricyanide solution was used to perform a functionalitysensor test with the portable potentiostat. The expected change in current peaks due to the redox reaction of the sample was observed.The operation of the sensor and portable potentiostat was then verified by successfullymeasuring different DNA concentrations of aster yellows and Coniella granati. The results confirmed that the potentiostat biosensor is capable to detect plant disease successfully.

[发布机构] Stellenbosch University