Surface gradient of functional heparin

A simple method for forming a functional gradient of unmodified heparin by adsorption onto a surface chemical gradient was reported to find effects of surface chemistry on the binding of heparin. It is seen that there is a significant increase in S content along the length of the gradient, starting at 0.25 at the octadiene end of the gradient and rising to 0.62 at the allyl amine end. The binding of Link_TSG6 increases across the gradient, while over the mid-portion of the gradient, the amount of bound heparin and bound protein increase in an equivalent manner. The functionality of the surface-bound heparin is found to be optimal when adsorbed to plasma-polymerized allyl amine surfaces with an N/C ratio of 0.15. Optimal protein binding is found to require a specific level of surface adsorption, which if exceeded, leads to heparin immobilized in a less functional form.