AVS 49th International Symposium
    Biomaterials Wednesday Sessions
       Session BI-WeP

Paper BI-WeP2
Oriented Immobilization of Anti-Human Chronic Gonadotropin for Biosensor Applications

Wednesday, November 6, 2002, 11:00 am, Room Exhibit Hall B2

Session: Biointerfaces and Surfaces II
Presenter: L. Liu, University of Washington
Authors: L. Liu, University of Washington
S. Chen, University of Washington
S. Jiang, University of Washington
Correspondent: Click to Email
The orientation of immobilized antibodies on solid surfaces, is important to performance of a biosensor. Our previous studies show that it is possible to control antibody orientation during physical adsorption via adjusting surface and solution properties. For biosensor applications, it is desirable to chemically immobilize antibody molecules on surfaces. Our previous studies further show that chemical linkers (e.g., NHS/EDC and GLU) used for chemical immobilization alter surface charges, thus antibody orientation. In this work, we present a new method, which combines the site-directed immobilization (via the conservative carbohydrate or histidine rich region located in the Fc portion of the IgG) and the charge-control methods, for the oriented immobilization of antibodies on self-assembled monolayers (SAMs)/Au(111). Monoclonal anti-hCG (human chronic gonadotropin) will be a model antibody studied in this work. Surface charge is adjusted by changing SAM terminal groups and solution pH values. Atomic force microscopy (AFM) is used to characterize adsorbed antibody molecules on surfaces. Low detection limit and saturated adsorbed amount in surface plasmon resonance (SPR) biosensors are determined in this work for various antibody immobilization methods. Results from this work show significant improvement over those based on conventional immobilization methods.