NAD-sensitive hydrogel for the release of macromolecules

A hydrogel membrane contg. immobilized ligands and receptors was synthesized and investigated for the controlled diffusion of test proteins (cytochrome C and Hb). Both Cibacron blue (ligand) and lysozyme (receptor) were covalently linked to dextran mols. that were subsequently crosslinked to form a gel. The resulting stable hydrogels contained both covalent and affinity cross-links such that their intrinsic porosities were sensitive to competitive displacers of the affinity interaction between lysozyme and Cibacron blue. Transport expts. in a twin chamber diffusion cell showed that as NAD was added to the donor side, the dissocn. of the binding sites between the Cibacron blue and the lysozyme led to an increase in protein diffusion through the hydrogel. The results showed that addn. of NAD caused a saturable concn.-dependent increase in the transport of both cytochrome C and Hb. This effect was shown to be both specific and reversible.