Self-assembled monolayer for toxicant detection using nucleic acid sensor based on surface plasmon resonance technique.

Double stranded calf thymus deoxyribonucleic acid (dsCT-DNA) has been covalently immobilized onto self-assembled monolayer (SAM) of beta-merceptoethanol (MCE) on gold substrates via N-ethyl-N'-(3-dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide chemistry for fabrication of the surface plasmon resonance (SPR) based biosensing device. The dsCT-DNA-MCE-SAM/Au bioelectrode has been characterized using electrochemical impedance spectroscopy, cyclic voltammetry, contact angle measurements and atomic force microscopy, respectively. This biosensing device has been utilized for detection of cypermethrin (0.0005 ppm) using electrochemical and SPR techniques, respectively. The mechanism of interaction of cypermethrin with dsCT-DNA immobilized onto MCE-SAM has been proposed.