Electrochemical identification of the property of peripheral nerve fiber based on a biocompatible polymer film via in situ incorporating gold nanoparticles

We report a simple electrochemical method for the identification of properties of peripheral nerve fibers, based on the detection of a neurotransmitter enzyme, acetylcholinesterase (AChE). A poly(diallydimethylammonium) (PDDA) adulterated poly(dimethylsiloxane) (PDMS) film is spin-coated on the surface of gold electrodes. Gold nanoparticles (AuNPs) are in situ synthesized on the polymer film, which act as electron antennae between the film and the electrode surface and also provide a biocompatible interface. Ibis PDMS-PDDA/AuNPs film shows different adsorption sites to choline oxidase (ChO) and AChE; after incubation with ChO, the polymer-gold nanocomposite film also shows excellent adsorption ability to AChE. Moreover the adsorption sites of AChE would not be blocked by bovine serum albumin (BSA) which provides a good platform for the quantitative amperometric determination of AChE via the oxidation of the enzymatically generated H2O2 in the bienzyme system in the presence of acetylcholine. The detection limit is down to 1.0 unit/mL. The polymer-gold nanocomposite film shows excellent anti-interference ability to the coexistent electroactive substances such as ascorbic acid. Thus it was applied to determine AChE in peripheral nerve fibers homogenates and identify the motor and sensory fibers for the first time. Compared with histochemical staining methods, the electrochemical technique shows good accurate rate and faster response, which has good potential for a clinical application.