Analytical Sciences

Voltammetric Evaluation of the Binding between Wheat Germ Agglutinin and Thionine/Glucose-modified Magnetic Microbeads

Kazuharu SUGAWARA,* Atsushi SENBONGI,* Naoto KAMIYA,* George HIRABAYASHI,* and Hideki KURAMITZ**

*Faculty of Education, Gunma University, Maebashi, Gunma 371-8510, Japan
**Department of Environmental Biology and Chemistry, Faculty of Science, University of Toyama, Toyama 930-8555, Japan

The binding between glucose residues and wheat germ agglutinin (WGA) on thionine/glucose-modified magnetic microbeads was evaluated using voltammetry. Thionine is an electroactive compound and has two amino groups. Thionine was immobilized to magnetic beads via cross-linking of the amino groups on the beads with an amino group on thionine. Glucose was bound to the other amino group of thionine via the formation of a Schiff base. The beads were only several micrometers in size the same size, as cells. WGA-binding to glucose on the bead surface blankets the thionine moiety. Thus, WGA-binding could be detected as a decrease in peak current of the thionine moiety.

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