Fast electrochemical deposition of CuO/Cu2O heterojunction photoelectrode: Preparation and application for rapid cathodic photoelectrochemical detection of L-cysteine

Cathodic photoelectrochemical (PEC) bioanalysis has been drawing more attention in recent years due to the advantages of excellent anti-interference capability. l-cysteine (Cys) is an essential sulfur-containing amino acid and has been intensively addressed as targets in previous anodic PEC bioanalysis. Herein a novel and simple cathodic PEC l-cysteine (Cys) sensor is reported, on the basis of facile electrochemical fabrication of CuO/Cu2O heterojunction photocathode and the selective interaction between the copper and Cys via the formation of CuS bond. The as-prepared sensor exhibited excellent biosensing performance in terms of high sensitivity, selectivity and stability. In such a sensor, the binding-induced decrease of cathodic photocurrent can be related to target concentration from 0 and 1.5 μM. This cathodic PEC Cys sensor exempted the use of expensive equipment and required no laborious sensor development procedures. We hope it can inspire more interest for further development of simple and practical PEC sensor toward important biomolecules.