Electrochemical Acetylcholinesterase Biosensor Based on Polylactide-Nanosilver Composite for the Determination of Anti-dementia Drugs

摘要

A new acetylcholinesterase biosensor has been developed for the determination of anticholinesterase drugs applied for neurodegenerative disease treatment. For this purpose, silver nanosendrites were deposited by potentiostatic electrolysis on a glassy carbon electrode covered with oligolactides cross-linked with p-tert-butylthiacliax[4]arene core in the cone, partial cone, and 1,3-alternate configurations. The roles of macrocycle configuration and electrolysis conditions on the silver depostion were characterized and optimal conditions selected for the subsequent immobilization of acetylcholinesterase. Silver nanoparticles provide higher response at low working potential (0.05 V) due to the electrostatic accumulation of silver ions and prevention of their leaching after reoxidation. The biosensor allows the determination of 10(-12) - 10(-7) M donepezil, berberine, and huperzine A within 20-30 s by the relative decay of the current related to the oxidation of thiocholine formed in enzymatic reaction. The reversible inhibition of immobilized acetylcholinesterase with huperzine A was quantified for the first time. The developed biosensor was employed for the analysis of spiked urine samples.