Research progress of biosensor based on enzyme single molecule nanocapsule technology

[ Instrument R&D of Instrumentation Network ] Recently, biosensors based on enzyme single-molecule nanocapsules (SMENs) technology developed by the team of researchers Lu Xianbo and Chen Jiping of the Ecological Environment Evaluation and Analysis Research Group of Dalian Institute of Chemical Physics, Chinese Academy of Sciences have made new progress. The core performances such as thermal stability, organic solvent tolerance, acid-base tolerance, storage stability, etc. have been improved qualitatively, and SMENs technology was first applied to the field of analysis and biosensing.

Enzyme biosensors have the advantages of simplicity, speed, cheapness, portability and miniaturization, and have broad application prospects in the fields of medical diagnosis, food, environment, etc., but their low stability is an obstacle restricting their application. Enzymes are protein molecules, which have significant selectivity and specificity as an efficient bioreactor. However, they are highly sensitive to the external environment (temperature, solvent, pH, etc.), and have a short shelf life and insufficient stability, which limits their application in different fields, as do enzyme biosensors. Therefore, the development of enzyme biosensors with high stability in different working environments to improve storage and service life is very important for broadening their applications in the fields of analysis, biomedical testing, wearable devices, implantable devices, etc. In traditional research, the nano-regulatory effect of nano-materials is usually used, and different enzyme molecule immobilization methods and sensing strategies are adopted (such as the use of biocompatible inorganic nano-materials as enzyme molecular immobilization units) to significantly improve the enzyme The sensitivity and detection limit performance of biosensors are not significant for improving the stability of enzyme biosensors.

The research team solved the stability problems that troubled the development of enzyme sensors with high-stability enzyme single-molecule nanocapsule technology, using glucose oxidase (GOx) and tyrosinase (Tyr) as model enzymes, respectively. In situ free radical polymerization strategy at room temperature, the single molecules of the above enzymes were encapsulated in a porous polymer shell, and single molecule enzyme nanocapsules (SMENs) with high activity and high stability were developed: glucose oxidase nanocapsules (nGOx) and Tyrosinase nanocapsules (nTyr). The polymer shell effectively stabilizes the internal GOx and Tyr cores, while the porous network structure realizes the rapid transportation of the substrate, thereby forming a class of new biocatalytic nanocapsules with outstanding activity and stability. The multiple covalent binding between the polymer thin layer and the enzyme molecule enhances the stability of the encased enzyme molecule, provides a good microenvironment for it, avoids structural denaturation under high temperature and strong acid-base conditions, and helps in organic Water molecules necessary for enzyme activity are retained during the operation of the solvent system. Taking thermal stability as an example, after incubating at 65°C for 2h, the relative activity of the sensor based on natural Tyr is only 23.2%, while the relative activity of the sensor based on nTyr can still maintain more than 52.7%. Sensors based on nGOx and nTyr show good performance in blood glucose detection and bisphenol A detection, respectively, and have significantly improved thermal stability, organic solvent tolerance, acid-base stability and long storage life. Biosensors based on new single-molecule enzyme nanocapsules can be applied to a variety of extreme application scenarios, and provide solutions for improving the stability of enzyme sensors.

The team is committed to improving the key performance of biosensors such as stability, sensitivity, detection limit, and developing real-time and rapid detection methods of important targets. Related research results were published in "Biosensors and Bioelectronics" and "Analytical Chemistry". The research work was supported by the National Natural Science Foundation of China and the Dalian Chemical Research Institute Innovation Research Fund.