Photoelectrochemical biosensor based on Bi2S3/Bi2O2CO3 for lactic acid detection

Photoelectrochemical biosensor based on Bi 2 S 3 /Bi 2 O 2 CO 3 heterojunction as photoelectrically active material and lactate oxidase was constructed for sensitive detection of lactic acid in serum. Topological transformation method was utilized to prepare Bi 2 S 3 /Bi 2 O 2 CO 3 composites, which can generate electron–hole pairs triggering photoelectrochemical reactions under light illumination. The Bi 2 S 3 /Bi 2 O 2 CO 3 heterojunction effectively promoted the separation and transportation of photogenerated electrons and holes, leading to improved photoelectric conversion efficiency. Lactic acid is catalyzed by lactate oxidase to generate H 2 O 2 , which reacts with photogenerated holes, leading to photocurrent increase, achieving quantitative detection of lactic acid. The prepared biosensor has a wide detection range for lactic acid from 0.01 mM to 10 mM, with detection limit as low as 0.006 mM. In addition, the detection of lactic acid in serum samples further validated the potential application of the sensor. Graphical abstract