University of Applied Sciences Utrecht 1 article published in JoVE Biochemistry Covalent Binding of Antibodies to Cellulose Paper Discs and Their Applications in Naked-eye Colorimetric Immunoassays Yanfen Peng1, Victor Van Gelder2, Anburaj Amaladoss1, Kadamb Haribhai Patel1 1School of Applied Science, Temasek Polytechnic, 2University of Applied Sciences Utrecht In this manuscript, periodate oxidation and glutaraldehyde cross-linking methods for covalent immobilization of antibodies on paper discs are presented. The binding activity of immobilized antibodies was evaluated. Based on these results, a glutaraldehyde cross-linking method was used to develop a novel paper-based immunoassay for immunoglobulin G (IgG) detection.