DNA-hybridization detection using light-addressable potentiometric sensor modified with gold layer

Single-stranded deoxyribonucleic acid (ssDNA) probes modified with thiol group were immobilized on the patterned gold surface of a light-addressable potentiometric sensor (LAPS) via gold-thiol bond. The LAPS chip immobilized with ssDNA probe was used as a working electrode in a scanning LAPS measurement system. After the working electrode was incubated with a solution containing strands of complementary target ssDNA, the photocurrent-voltage curves of LAPS shift with increasing target ssDNA concentration. On the contrary, in a control experiment, practically no shift of photocurrent-voltage curve was observed if the LAPS chip was incubated with a solution containing mismatch ssDNA. This provides a convenient and label-free method for the detection of DNA hybridization and therefore, a promising approach for the development of novel LAPS-based DNA chips.