Blood Compatible Hydrogel Coatings

Surface-attached hydrogels show a great potential as blood compatible coatings. Their anti-thrombogenic properties arise from their strong swelling in aqeuos environments. The high water uptake leads to a strong stretching of the chains. Proteins cannot adsorb on these surfaces either for size exclusion reasons or because any diffusion into the strongly swollen coatings would lead to additional swelling of the surface-attached chains. This is entropically very unfavorable.

Figure 1: Protein adsorption is the first step in blood coagulation. Strongly swollen surfaces repel proteins and are therefore good candidates as blood compatible materials. Our picture shows cells that adhere well on collapsed polymer surfaces and a clean hydrogel surface after exposure to cells.

The strong protein repellency also prevents the adhesion of cells (Figure 1) or blood platelets. The blood compatibility of these coatings is, hence, caused by the bio inert character of the hydrogel coatings.