Ultrasensitive photoelectrochemical biosensing of multiple biomarkers on a single electrode by a light addressing strategy.

Ultrasensitive multiplexed detection of biomarkers on a single electrode is usually a great challenge for electrochemical sensors. Here, a light addressable photoelectrochemical sensor (LAPECS) for the sensitive detection of multiple DNA biomarkers on a single electrode was reported. The sensor was constructed through four steps: (1) immobilization of capture DNA (C-DNA) of different targets on different areas of a single large-sized gold film electrode, (2) recognition of each target DNA (T-DNA) and the corresponding biotin-labeled probe DNA (P-DNA) through hybridization, (3) reaction of the biotin-labeled probe DNA with a streptavidin-labeled all-carbon PEC bioprobe, and (4) PEC detection of multiple DNA targets one by one via a light addressing strategy. Through this principle, the LAPECS can achieve ultrasensitive detection of three DNA sequences related to hepatitis B (HBV), hepatitis C (HCV) and human immunodeficiency (HIV) viruses with a similar wide calibration range of 1.0 pM ∼ 0.01 μM and a low detection limit of 0.7 pM by using one kind of PEC bioprobe. Moreover, the detection throughput of LAPECS may be conveniently expanded by simply enlarging the size of the substrate electrode or reducing the size of the sensing arrays and the light beam. The present work thus demonstrates the promising applications of LAPECS in developing portable, sensitive, high-throughput, and cost-effective biosensing systems.