AVS 46th International Symposium
    Biomaterial Interfaces Group Tuesday Sessions
       Session BI-TuP

Paper BI-TuP15
Surface Functionalization Strategies for Miniature Multichannel Biosensing

Tuesday, October 26, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: H.B. Lu, University of Washington
Authors: H.B. Lu, University of Washington
J. Homola, University of Washington
C.T. Campbell, University of Washington
B.D. Ratner, University of Washington
S.S. Yee, University of Washington
Correspondent: Click to Email
Biosensor development has advanced towards highly integrated, multichannel array configurations with more detection power and faster speed. Robust surface functionalization methods for immobilizing sensing molecules and making non-fouling surfaces are needed. Also, precise spatial control of surface functionalization is valuable. In this presentation, various surface functionalization methods including orthogonal self-assembly (OSA), masked plasma polymerization and protein contact printing are introduced. The potential of these methods for precisely immobilizing sensing biomolecules to specific surface regions, or creating a non-fouling area using passivation molecules, is discussed. We used a dual-channel surface plasmon resonance (SPR) sensor with a thin tantalum oxide (Ta2O5) overlayer configuration for demonstrating the feasibility of these surface functionalization methods, as well as for further developing a miniaturized multichannel biosensor. The high refractive index dielectric Ta2O5 overlayer covers part of the gold surface to excite part of the incident light in a higher wavelength and thus produce a second SPR dip besides the original gold SPR dip. To use this second SPR dip as an internal reference channel, the surface functionalization methods were used to deliver biosensing molecules (e.g. antibodies) or passivation molecules (e.g. oligo(ethylene glycol) or bovine serum albumin) to the gold or the Ta2O5 surface respectively. The optical nature of such an SPR sensor configuration requires precise delivery of molecules to these two surface regions in order to separate signal from the two channels. Therefore, it provides an excellent tool for demonstrating the spatial control ability of the surface functionalization methods used. The surface functionalization strategies described in this paper should have general applicability for developing miniaturized multichannel biosensors in other formats as well.