Aptamer-functionalized magnetic nanoparticles conjugated organic framework for immobilization of acetylcholinesterase and its application in inhibitors screening

Construction of new enzyme reactor based on aptamer functionalized magnetic nanoparticles conjugated organic framework (COF) for acetylcholinesterase immobilization has been an enabling endeavor in this work. The aptamer against acetylcholinesterase was selected through a method based on capillary electrophoresis in one round. A new magnetic COF material rich of carboxyl groups was firstly synthesized, and its surface was then modified with the selected aptamer through covalently linking. Acetylcholinesterase was immobilized to fabricate the enzyme reactor Fe₃O₄@COF-Apt-AChE through the high affinity and specificity with its binding aptamer. The as constructed enzyme reactor was comprehensively characterized and the key factors that affected its catalysis efficiency were investigated in detail. Owing to the surface modification of the magnetic COF materials by aptamer for acetylcholinesterase immobilization, the immobilized enzyme exhibited improved substrates affinity. What's more, good reusability (more than 8 times) and prolonged stability (enzyme activity still kept at 90% after 42 days) were also achieved. Finally, the enzyme reactor could be applied in AChE inhibitors screening, which expanded its application capability. The proposed protocol not only paves a new way for fabrication of novel aptamer functionalized magnetic COF materials as enzyme reactors, but also indicates a broadened application of the integration of aptamer and its enzyme.