Immobilization of antibodies on mesoporous silica materials and their binding abilities to antigens

Mesoporous silicas (MPS) are potential materials for adsorption of antibodies on their surface as they have the following features: a) an ordered pore network and b) It high surface area. These unique features make MPS an excellent candidate as an immobilizing carrier for immunoassays. We present here the relationship between antibody molecules and pore diameters of various MPS; moreover, the thermal stability and the organic solvent stability of antibodies immobilized on MPS are evaluated. From six MPS, the entire amount of antibodies (44 mu g) was adsorbed on four MPS (3 mg; pore sizes: 3.4, 11.0, 15.0, and 23.1 rim) but not on MPS with 5.8 and 8.1 nm pores. However, the binding activities of antibodies to antigens were high only on MPS with 3.4 and 5.8 nm pores. Regarding the thermal stability of antibodies immobilized on MPS, the antibody immobilized on 23.1 nm pore MPS kept about 30% activity even after 3 h at 80 degrees C, but that on 3.4 nm pore MPS was markedly decreased (<10% activity) after that time. These results indicated that the Fab fragment, which is an antigen binding site of the antibody, was incorporated inside larger pores but remained outside smaller pores. (C) 2011 The Ceramic Society of Japan. All rights reserved.