An Electrochemical DNA Biosensor for Ganoderma Boninense Pathogen of the Oil Palm Utilizing a New Ruthenium Complex, [Ru(dppz)2(qtpy)]Cl2

Abstract

A new DNA biosensor for Ganoderma boninense, pathogen of the oil palm has been developed. The system was developed based on a gold electrode (AuE) modified with a conducting polymer film of poly(3,4-ethylenedioxythiophen)-poly(styrenesulfonate) (PEDOT-PSS) containing silver nanoparticles (AgNPs). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques were employed to characterize and optimized the detection system. The modified electrode exhibited higher electrical conductivity compared to the bare electrode. A DNA probe for Ganoderma boninense was immobilized on the modified electrode and a new ruthenium complex was employed as a marker for monitoring hybridization of target DNA. The effect of hybridization temperature and time was studied and was found to be optimal at 45 °C with hybridization time of 35 minutes. Effect of different concentration of target DNA ranged from 1.00 × 10-15 M to 1.00 × 10-9 M was studied and calibration plot with correlation of 0.969 and a detection limit of 6.20 × 10-16 M was obtained. The newly synthesized ruthenium complex has shown a good affinity towards hybridized DNA and proven to be a good hybridization indicator. This work is the first ever reported biosensor based detection method for Ganoderma boninense.