The Effect of Pre-Polymeric Solution and Subsequent Encapsulation in Hydrogel Membranes on the Stability and Biological Activity of Horse Myoglobins

Proteins are biological macromolecules which have a unique spatial conformation. Once this 3D spatial conformation is affected the protein's biological stability and activity can be severely limited. For these reasons, this investigation focuses on the effects of pre-polymeric solution components on the behavior of proteins to be encapsulated by the entrapment technique in anionic, cationic, and neutral hydrogel membranes. Equine skeletal muscle myoglobin (MMb), and equine heart myoglobin (HMb) were employed as model molecules. Three hydrogel morphologies were examined: methacrylic acid-poly(ethylene glycol) dimethacrylate (n=1000) (MAA-PEGDMA1000), dimethylamino- ethyl methacrylate-poly(ethylene glycol) dimethacrylate (n=1000) (DMAEM-PEGDMA1000), and polyethylene glycol) (200) monomethyl ether methacrylate-poly(ethylene glycol) dimethacrylate (n=1000) (PEGDMA200-PEGDMA1000). Stability of the proteins in the pre-polymeric solution was assessed by UV- vis spectroscopy and the optimized morphologies were synthesized and the biological activity of both heme-proteins was assessed by oxidation-reduction reactions of the heme group. It was observed that while there was no displacement of the Soret bands of the proteins in the pre-polymeric solution, significant blue shifts were observed for the encapsulated proteins. Subsequent oxidation-reduction of the proteins caused shifts of the Soret bands as would be expected. However, the displaced peaks were not at their anticipated wavelengths. Other analyses will be performed on the membranes to better comprehend these results.