Immobilization of acetylcholinesterase on nanostructure polyacrylonitrile membranes.

PAN membranes with integrated gold nanoparticles (GNPs) into membrane pores were prepared for immobilization of acetylcholinesterase. Two types of polymer membranes were used-non-modified and chemically modified with NaOH. PAN+GNP membranes were investigated with respect to their water-permeation and electron-conducting properties and the results were compared to those, obtained for the initial membranes without GNPs. The SEM analyses showed morphology change in the different membranes. The chemical modification was an essential step in the preparation procedure in order to obtain more homogeneous distribution of the GNPs. AChE was covalently immobilized onto nanostructured membranes using 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide hydrochloride. The relationship between immobilization factors and enzyme activity were examined by the series of contour plots. The selections of the immobilization variable range were extremely precise in the 3-level-3-factor fractional design. The results indicated that the optimal conditions for AChE immobilization were: 0.025% enzyme solution; immobilization temperature, 4 degrees C and immobilization time, 15 h. The biochemical characteristics and kinetic parameters of immobilized enzyme were determined.