Simple design of cast myoglobin/polyethyleneimine modified electrodes

Abstract

Negatively charged myoglobin (at pH values above its isoelectric point) was immobilized with the positively charged polyion polyethyleneimine (PEI) on pyrolytic graphite electrodes. A modified form of the common layer-by-layer technique was proposed, which consisted in forming non-ordered cast polyion films. The modified Mb electrodes obtained by both techniques were compared by cyclic voltammetry. The cast polyion technique gave less reproducible results but enable the immobilization of higher percentages of the total quantity of protein required to prepare the electrodes. The electrochemical properties of the negatively charged myoglobin were determined, and its capability to catalyze the electrochemical reduction of oxygen and the dechlorination of trichloroacetic acid was demonstrated. The mechanisms are discussed, and the modified pathway that has been proposed to take into account the influence of pH in the Mb-catalyzed reduction of oxygen was confirmed here.

Dechlorination of chloroacetic acids by electrocatalytic reduction using activated silver electrodes in aqueous solutions of different pH

“…However, the reductive dehalogenation of HAAs at the most commonly used cathodes [10][11][12][13][14] occurs at very negative potentials, where concomitant reduction of water may take place, resulting in abundant volatile H 2 and a decrease of current efficiency. Bioelectrochemically catalytic reduction [15][16][17][18][19] is an advanced technology for decomposition of HAAs in drinking water, they are, however, still in need of improvement, particularly with respect to immobilization and activity-keep of the used enzymes or enzyme-like proteins.…”