title: Immobilization of antibody fragment for immunosensor application based on surface plasmon resonance.
abstract: Biosurface fabrication using the Fab' fragment of immunoglobulin (IgG) was carried out by self-assembly (SA) technique. The pepsin-digested monoclonal antibody (Mab) against bovine insulin containing the F(ab')(2) fragment and residual proteins was separated using affinity chromatography and dialysis. To prevent the nonspecific binding of F(ab')(2) onto gold (Au) substrate, the native disulfide bridge was reduced using dithiothreitol (DTT) to convert F(ab')(2) into Fab', which made the immobilization to be carried out via the native thiol (-SH) group. The fabricated biosurface using SA technique showed the formation of stable thin film through AFM topography. Through the concentration change of DTT and Fab', the absorption characteristics against the Au surface were investigated using surface plasmon resonance (SPR) with the flow cell. The amount of immobilized antibody fragment and the antigen binding capacity were regulated with respect to the reduction state and concentration of F(ab')(2). Based on the biosurface of the fabricated Fab', the insulin-detection was carried out by the measurement of SPR. The proposed antibody surface could successfully detect the bovine insulin at the concentration from 100 ng/mL to 10 microg/mL.
authors.affiliation: Department of Chemical and Biomolecular Engineering, Sogang University, Mapo-gu, Seoul 121-742, Republic of Korea.
authors.forename: Woochang
authors.initials: W
authors.lastname: Lee
authors.forename: Byung-Keun
authors.initials: BK
authors.lastname: Oh
authors.forename: Won Hong
authors.initials: WH
authors.lastname: Lee
authors.forename: Jeong-Woo
authors.initials: JW
authors.lastname: Choi
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D002417:Cattle; D004591:Electrophoresis, Polyacrylamide Gel; D007140:Immunoglobulin Fab Fragments; D007328:Insulin / Q000032:analysis; D007700:Kinetics; D018625:Microscopy, Atomic Force; D020349:Surface Plasmon Resonance; D013997:Time Factors
chemical_list: D000911:Antibodies, Monoclonal; D007140:Immunoglobulin Fab Fragments; D007328:Insulin