Bisphenol A (BPA), one of the most important endocrine disrupting chemicals, is a threat to human and wildlife health. Electrochemical enzyme biosensor has been regarded as ideal alternative analytical technique for ultrasensitive and rapid detection of BPA, while the unstable and easily deactivated nature of enzyme limits its development. In order to improve the stability of enzyme, tyrosinase was chosen as a model enzyme, and tyrosinase nanocapsules (nTyr) were prepared by encapsulating a single tyrosinase molecule into a thin network polymer shell through in-situ polymerization method in aqueous solution. The characterization of particle size distribution, TEM and FTIR indicated the successful formation of single tyrosinase molecule nanocapsule. And the porous network polymer shell of nTyr ensured the maintenance of tyrosinase activity and fast substrate transportation. The obtained nTyr was used to construct an electrochemical biosensor for BPA detection, exhibiting a low detection limit of 12 nmol L^-1 and a wide linear range from 5 × 10^-8 to 2 × 10^-6 mol L^-1. Compared with native tyrosinase, the nTyr based biosensor displayed dramatically enhanced stability including thermal stability, organic solvent tolerance and acid/base tolerance. The excellent performance of nTyr based biosensor was not only attributed to the protection of biocompatible rigid polymer shells, but also the multipoint covalent attachments between tyrosinase cores and polymer shells. The robust biosensor was further used for rapid detection of BPA leached from plastic products with satisfactory results. The nTyr based nano-biosensor provides a prospective solution to resolve the stability problem of enzyme biosensors in different application scenarios.

双酚A（BPA）是最重要的破坏内分泌的化学物质之一，对人类和野生生物的健康构成威胁。电化学酶生物传感器已被认为是超灵敏和快速检测BPA的理想替代分析技术，而酶的不稳定和容易失活的性质限制了它的发展。为了提高酶的稳定性，选择酪氨酸酶作为模型酶，并通过水溶液中原位聚合法将单个酪氨酸酶分子包封在薄的网络聚合物壳中制备酪氨酸酶纳米胶囊（nTyr）。粒度分布，TEM和FTIR的表征表明成功形成了单个酪氨酸酶分子纳米胶囊。nTyr的多孔网络聚合物外壳确保了酪氨酸酶活性的维持和快速的底物运输。获得的nTyr用于构建BPA检测的电化学生物传感器，其检测限低至12 nmol L^-1且线性范围从5×10 ^-8到2×10 ^-6  mol L ^-1。与天然酪氨酸酶相比，基于nTyr的生物传感器显示出显着增强的稳定性，包括热稳定性，有机溶剂耐受性和酸/碱耐受性。基于nTyr的生物传感器的出色性能不仅归因于对生物相容性刚性聚合物壳的保护，而且还归因于酪氨酸酶核心与聚合物壳之间的多点共价连接。坚固的生物传感器还被用于快速检测从塑料产品中浸出的双酚A，结果令人满意。基于nTyr的纳米生物传感器为解决酶生物传感器在不同应用场景下的稳定性问题提供了前瞻性的解决方案。