Defective Se-doped In2S3 nanomaterial-based photoelectrochemical biosensor for the ultrasensitive detection of chloramphenicol

The sensitive and accurate detection of chloramphenicol is of great significance due to its environmental toxicity, which has received particular attention. Herein, a novel defective Se-doped In2S3 (In2S3-xSex) nanostructure with excellent photoelectrochemical (PEC) performance was designed to fabricate a PEC biosensor for the ultrasensitive detection of chloramphenicol (CAP). Specifically, In2S3-xSex was prepared through a one-step hydrothermal strategy by using Na2SeSO3 as the selenium source. We demonstrated that Se doping improved the separation of photocarriers and the absorption of light, resulting in a markedly enhanced photocurrent compared to that of pristine In2S3. In addition, a target-triggered recycling signal amplification procedure was designed to further develop a PEC biosensor by using In2S3-xSex as a signal indicator and SiO2 as a quencher. The fabricated CAP PEC biosensor showed high sensitivity, with a detection limit of 17 fM in a wide linear range from 50 fM to 10 nM. Importantly, the proposed PEC biosensor exhibited excellent selectivity, stability and reproducibility. This sensor was shown to offer great opportunities for the accurate detection of trace antibiotics and various environmental contaminants by altering the corresponding aptamers.