AVS 51st International Symposium
    Biomaterial Interfaces Wednesday Sessions
       Session BI-WeA

Paper BI-WeA1
PEG Modified Trichlorosilanes as Protein Repellent Coatings for Oxide Surfaces

Wednesday, November 17, 2004, 2:00 pm, Room 210D

Session: "Passive" and Non-Fouling Surfaces
Presenter: R. De Palma, IMEC, Belgium
Authors: R. De Palma, IMEC, Belgium
K. Jans, KULeuven, Belgium
K. Bonroy, IMEC, Belgium
W. Laureyn, IMEC, Belgium
G. Maes, KULeuven, Belgium
C. Van Hoof, IMEC, Belgium
Correspondent: Click to Email
The construction of oxide based microelectronic devices interfaced with biological components requires methods for assembling biomolecules on their surfaces in a controlled manner. Examples include biosensors, chip-based diagnostic assays and biomaterials used for implants and tissue engineering. A key issue in the design of analytical devices which contact biomolecules is that non-specific adsorption of biological species, particularly proteins, can limit their performance. Surface-bound poly(ethyleneglycol) is a powerful reagent to construct protein repellent surfaces on various substrates. Most procedures reported to yield PEG layers on oxides require several steps and thus decrease the surface controllability. To overcome the problems encountered during PEG surface modification, we have synthesized novel reagents which combine the silane surface modification properties and the protein resistant properties of short PEG (@<=@ 6) units to generate robust coatings for glass and metal oxides. Tantalum was used as a substrate because of the high chemical stability of its thin passivating oxide and was found to play an important role in the silane SAM formation. The molecular architecture of the deposited silane layers and the PEG chain conformation was studied using contact angle measurements, XPS, AFM, RAIRS, LDI-TOF-MS and ellipsometry. The non-specific adsorption of human serum and its 4 most abundant proteins were elaborated using quartz crystal microbalance with dissipation monitoring (QCM-D) and confocal fluorescence microscopy. The protein repellent properties of the PEG silane SAMs were shown to be strongly correlated to the PEG chain length and their molecular architecture. The correlation between the PEG length and the viscoelastic properties of the adsorbed protein film have led to a better insight into the phenomenon of protein repellence. Future work will involve the deposition of mixed PEG silane SAMs to further improve the protein resistant properties.