Highly Stable Magnetite Modified with Chitosan, Ferrocene and Enzyme for Application in Magneto-Switchable Bioelectrocatalysis

Magnetic fields have been used in Bioelectrochemistry to carry enzymes or redox mediators immobilized on magnetite (Fe3O4) to the electrodes surface, providing a switchable control of faradaic current from biocatalysis. In this work, it is reported an advance in the magnetic control of bioelectrochemical reactions, by construction of a system containing simultaneously a magnetic particle (for controlled driving), an enzyme (for biocatalysis) and a redox mediator (for mediation of electron transfer). The advance was attained by synthesis of a new material (Fe3O4-Chi-Fc/GOx) that consists of Fe3O4 particles modified with insoluble ferrocene (Fc) and chitosan (Chi) cross-linked with glucose oxidase (GOx). When this material was used in electrochemical studies, an increase of 70% was observed in the catalytic current of glucose oxidation when 0.24 T was applied perpendicularly to electrode plane. This is the first time that a control of the bioelectrocatalytic process was achieved using enzyme, mediator and magnetite in a unique system switched by a magnetic field.