Platelet-surface interactions: the role of adsorbed plasma proteins on surface gradient

• Concept: the presentation of varying surface chemistry in a form of linear surface gradients allows for a parallel approach in testing the effect of adsorbed plasma protein layers on platelet activation and adhesion.

Schematics of the surface gradient approach: mixing of "red" and "blue"chemistry creates a new surface property that does not have to be a simple additive mixture of the two chemistries.

• A new versatile surface chemistry based on UV oxidation of mercaptopropyl silane compound allows for modular build-up of surface layers.

Schematics of the mercaptopropyl trimethoxy silane coupling to fused silica surface, followed by UV photo oxidation of terminal sulfhydryl to generate a gradient. Further selective conjugation of unoxidized sulfhydryls is used to create novel gradient types. The conjugation candidates: maleimide, iodoacetate, bromoethylamine, pyridyl disulfide and many others (B. Wright, V. Hlady unpublished).

• Albumin binding from ternary protein mixture (albumin-AF488 + IgG + fibrinogen, in 1/100 plasma concentration dilution) to MTS gradient surface is followed using spatio-temporally resolved total internal reflection fluoresence (st-TIRF).

The result of spatio-temporally resolved TIRF experiment in which AF488-labeled albumin adsorbed to the one centimeter long MTS gradient surface from a ternary protein mixture (albumin-AF488 + IgG + fibrinogen, in their respective 1/100 plasma concentration dilution) (Y.X. Ding and V. Hlady, unpublished).