Dual-mode biosensor using Tb–Cu MOF@Au nanoenzyme to effectively quench the photocurrent of Bi2O3/Bi2S3/AgBiS2 heterojunction and emit fluorescence for neuron-specific enolases detection

• Published in: Talanta (Oxford) 2024-09, Vol.277, p.126346, Article 126346
• Main Authors: Fu, Junqiang, Wu, Tingting, Kuang, Xuan, Xu, Kun, Ren, Xiang, Wu, Dan, Ma, Hongmin, Li, Faying, Liu, Lei, Wei, Qin
• Format: Article
• Language: English
• Subjects: ascorbic acid; Bi2O3/Bi2S3/AgBiS2; biosensors; detection limit; disease detection; Dual-mode biosensor; electric current; energy; fluorescence; Neuron-specific enolase; oxidation; phosphopyruvate hydratase; Tb–Cu MOF@Au
• ISSN: 0039-9140; 1873-3573; 1873-3573
• DOI: 10.1016/j.talanta.2024.126346

A novel dual-mode biosensor was constructed for the ultrasensitive detection of neuron-specific enolase (NSE), utilizing Tb–Cu MOF@Au nanozyme as the signal label to effectively quench the photoelectrochemical (PEC) signals of Bi2O3/Bi2S3/AgBiS2 composites and initiate fluorescent (FL) signals. First, Bi2O3/Bi2S3/AgBiS2 heterojunction with excellent photoelectric activity was selected as the substrate material to provide a stable photocurrent. The well-matched energy levels significantly enhanced the separation and transfer of photogenerated carriers. Second, a strategy of consuming ascorbic acid (AA) by Tb–Cu MOF@Au nanozyme was introduced to improve the sensitivity of the PEC/FL biosensor. Tb–Cu MOF@Au not only could catalyze the oxidation of AA, but the steric effect further reduced the contact of AA with the substrate. More importantly, in the presence of H2O2, a significant fluorescence was produced from Tb3+ sensitized by the oxidation products of AA. Based on the above strategies, a highly stable and sensitive dual-mode biosensor was proposed for accurate NSE determination. Third, the developed dual-mode biosensor demonstrated excellent performance in detecting NSE. In this study, the PEC method demonstrated a wide detection range from 0.00005 to 200 ng/mL with a low detection limit of 20 fg/mL. The FL method exhibited a linear range from 0.001 to 200 ng/mL with a detection limit of 0.65 pg/mL. The designed biosensor showed potential practical implications in the accurate detection of disease markers. [Display omitted] •A novel dual-mode biosensor for NSE detection was successfully fabricated.•Bi2O3/Bi2S3/AgBiS2 was used as photoactive matrix to provide stable PEC signal.•Tb–Cu MOF@Au was used to quench the photocurrent and generate a fluorescent.•The biosensor exhibited a low detection limit of 20 fg/mL.