AVS 56th International Symposium & Exhibition
    Biomaterial Interfaces Thursday Sessions
       Session BI-ThP

Paper BI-ThP8
Characterizing the Carbohydrate Microarray: XPS, ToF-SIMS, SPR, and ELLA Analysis of Glycan-Modified Surfaces

Thursday, November 12, 2009, 6:00 pm, Room Hall 3

Session: Biomaterial Interfaces Poster Session II (Arrays, Sensing, Micro/Nanofabrication, SPM)
Presenter: F. Cheng, University of Washington
Authors: F. Cheng, University of Washington
M. Dubey, University of Washington
H. Nguyen, University of Washington
S. Jing, University of Washington
J. Burk-Rafel, University of Washington
M. Dhayal, Centre for Cellular and Molecular Biology, India
D. Ratner, University of Washington
Correspondent: Click to Email
Self-assembled Monolayers (SAMs), especially alkanethiols on gold, have been extensively used as model system for studying surface modification strategies. In this work, we utilize this platform to fabricate carbohydrate-modified biosensors composed of mixed monolayers of mannose headgroups and oligo(ethylene glycol) (OEG) moieties on gold. We have extensively used x-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), surface plasmon resonance (SPR), and enzyme-linked lectin assay (ELLA) to understand the composition, structure and reactivity of these mixed SAMs to carbohydrate-binding proteins (lectins). XPS and ToF-SIMS results give a clear indication that the composition of mannose on the surface is directly proportional to its molar ratio in solution. However, when these sensors are exposed to lectins, XPS shows that the amount of protein is inversely proportional to the amount of mannose present on the surface. We performed SPR studies to obtain a quantitative comparison of the amount and multivalent binding of lectins on these mixed SAMs. Detailed study of this system using XPS, ToF-SIMS, SPR and ELLA suggests that an optimum density of mannose on the surface is required to improve the sensitivity and stability of these sensors.