Bio-inspired enzyme-immobilized nanoreactors with cascade catalytic reaction for accurate detection of cholesterol

Although enzyme-based biochemical detection offers high accuracy and speed, their applications are limited by the instability of biological enzymes. Developing an enzyme-encapsulated system with high activity, strong stability, and high reaction efficiency is a crucial strategy for cholesterol detection. Herein, we developed a bionic artificial cell with hollow multishelled structures (HoMS) covered by phospholipid membranes. The compartmentalized structure and selective permeability of this artificial cell enable stable enzyme encapsulation and efficient signal transmission, achieving rapid and accurate cholesterol detection through signal cascade amplification. Cholesterol oxidase-loaded HoMS@DPPC was used to initiate cholesterol oxidation reaction, and the resulting intermediate product H₂O₂ was regarded as signal molecules to enter horseradish peroxidase-loaded HoMS@DPPC, promoting Amplex Red to produce resorufin. The amplification of cholesterol signal mediated by cascade catalysis makes the present system applicable to the detection of cholesterol, and the method shows high selectivity and accuracy, with a detection range of 0.05–0.3 mM and a detection limit of 4.9 µM. It can be used for the detection of cholesterol in animal serum with a recovery of 90.8% to 104.9%, highly consistent with the results of commercial detection methods. Furthermore, the system can be integrated with smart devices to build an intelligent colorimetric platform, enabling the integration of image analysis and cholesterol concentration detection, opening up a new path for accurate and rapid biochemical detection.