Gold nanorods and graphene oxide enhanced BSA-AgInS2 quantum dot-based photoelectrochemical sensors for detection of dopamine

Abstract

Quantum dot (QD)-based photoelectrochemical (PEC) sensors have attracted considerable attention owing to their advantages, while the heavy metal ions existed in most investigated QDs limit their practical applications in biochemical detection. Herein, we present a PEC biosensor based on bovine serum albumin-coated AgInS2 QDs (BSA-AgInS2) with low toxicity for the sensitive detection of dopamine (DA). In this study, the fabrication and measurement conditions were optimized first. Furthermore, different nanomaterials were introduced as hybrid nanocomposites to enhance the sensing properties. The experimental results revealed that gold nanorods (AuNRs) improved the photoelectric properties, and graphene oxide (GO) enhanced the catalytic properties on DA of BSA-AgInS2 QD-based PEC sensors. Due to the enhancement effects of both GO and AuNRs, the sensitivity and limit of detection (LOD) of BSA-AgInS2/AuNRs/GO-based PEC sensors reached 4.5 nA/μM and 66.8 nM, respectively, in the linear range of 0.3–10 μM when optimal concentrations of GO (0.17 mg/mL) and AuNRs (66.75 μg/mL) were used. Moreover, our designed PEC sensors showed high selectivity for DA over the interfering substances of ascorbic acid (AA) and uric acid (UA). Thus, a universal strategy to enhance the sensing properties of PEC sensors by the improvement of photoelectric and catalytic properties separately was proven.