Portable, Self-Powered, and Light-Addressable Photoelectrochemical Sensing Platforms Using pH Meter Readouts for High-Throughput Screening of Thrombin Inhibitor Drugs

In this work, a self-powered, portable, and light-addressable photoelectrochemical sensor (P-LAPECS) is developed for efficient drug screening using a handheld pH meter readout. The sensor, which employs thrombin inhibitors as the drug model, is constructed by evenly immobilizing biotin-labeled and thrombin-cleavable peptides on eight separated sensing zones of a single gold film electrode. The incubation of each peptide sensing zone with thrombin leads to the reduction of binding sites for streptavidin-labeled fullerene (C₆₀) PEC bioprobes, which directly reflects the activity of thrombin by the variation of both photocurrent and photovoltage, and therefore allows the screening of thrombin inhibitors using either a single-channel electrochemical analyzer or a portable pH meter. Consequenty, the inhibition efficiency evaluation of multiple thrombin inhibitors can be achieved by just one electrode, and the screening result obtained by the pH meter is very close to that acquired by the electrochemical analyzer. Moreover, P-LAPECS can realize the light-addressable detection of thrombin with a detection limit as low as 0.05 pM. The present work thus demonstrates the possibility of constructing portable, inexpensive, sensitive, and high-throughput biosensing platforms using ubiquitous pH meters for laboratories all over the world.