Ultrasensitive electrochemical determination of bisphenol A in food samples based on a strategy for activity enhancement of enzyme: Layer-by-layer self-assembly of tyrosinase between two-dimensional porphyrin metal-organic framework nanofilms

Bisphenol A, as an endocrine disruptor, has aroused widespread attention for its safety. Electrochemical enzyme based biosensor is a powerful tool for the determination of bisphenol A, but the instability of enzyme limits its practical application. Assembling biomacromolecules in metal-organic frameworks (MOFs) can preserve their biological functions in harsh environments. In this work, tyrosinase (Tyr) was assembled layer-by-layer in an ultrathin copper-porphyrin MOF nanofilm (Tyr@Cu-TCPP) via a simple one-step solvothermal method, and an ultrasensitive electrochemical biosensor was fabricated for bisphenol A detection. Compared with native Tyr or a traditional surface-adsorbed structure of Tyr on Cu-TCPP nanofilm, Tyr@Cu-TCPP retained superior enzymatic activity when exposed to elevated temperatures and extreme acidity or basicity, the sensor exhibited significantly enhanced thermal and long-term storage stability, as well as acid/base tolerance. In addition, the electrochemical biosensor based on Tyr@Cu-TCPP showed significantly enhanced sensing performance, including a wide linear range of 3.5 nM-18.9 mu M, with a detection limit of 1.2 nM. For the first time, the fabrication of an electrochemical biosensor relying on enzyme assembled between two-dimensional MOF nanomaterial layers has been reported. This method greatly improves the activity and stability of the biosensor, and provides a promising strategy for promoting the application of enzyme biosensors in harsh detection environments, discovering and controlling environmental pollutants and food hazards.

Automated summary

This research developed a new electrochemical biosensor for the detection of bisphenol A by assembling tyrosinase in a metal-organic framework. The sensor exhibited enhanced enzymatic activity and stability compared to traditional methods and was capable of detecting bisphenol A in extreme conditions.