IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Biomaterials Monday Sessions
       Session BI-MoM

Paper BI-MoM3
Surface Docking Sites for Macromolecules: Interface Architecture based on PLL-g-PEG/PEGbiotin-(Strept)avidin

Monday, October 29, 2001, 10:20 am, Room 102

Session: Molecular Recognition
Presenter: N.-P. Huang, ETH Zürich, Switzerland
Authors: N.-P. Huang, ETH Zürich, Switzerland
J. Vörös, ETH Zürich, Switzerland
S.M. De Paul, ETH Zürich, Switzerland
M. Textor, ETH Zürich, Switzerland
N.D. Spencer, ETH Zürich, Switzerland
Correspondent: Click to Email
Surface docking sites (nanoscale islands) are desirable for the specific adhesion of macromolecules, such as proteins and oligonucleotides, onto surfaces. The surrounding areas of such docking sites should be non-adhesive so that the adsorbed macromolecules are prevented from denaturing after adsorption. We have mixed poly(L-lysine)-g-poly(ethylene glycol) (PLL-g-PEG) and a variant of PLL-g-PEG in which some of the PEG chains are biotinylated (PLL-g-PEG/PEGbiotin) to form a novel polymeric interface, in order to tailor chip surfaces in terms of non-specific and specific analyte-surface interactions. By means of optical waveguide lightmode spectroscopy (OWLS), streptavidin and avidin are shown to bind specifically to the biotin-functionalized PEG, while the resistance of the remaining PEG chains to protein adsorption yields a high specific-binding-to-non-specific-binding ratio. Subsequent binding of biotinylated goat-anti-rabbit immunoglobulin (@alpha@RIgG-biotin) to (strept)avidin as a capture molecule allows the system to be used as an immunoassay for the target molecule, rabbit immunoglobulin (RIgG). Changing the ratios of PLL-g-PEG and PLL-g-PEG/PEGbiotin in the mixture changes the distribution of docking sites (biotin sites) on the interface and, thus, allows optimization of the sensing response. The effects of protein charge and the ionic strength of the buffer are also explored. We expect that such a platform could serve as a powerful tool for the investigation of molecular recognition effects.