The chemical composition of a hydrogel is the key factor affecting blood compatibility of obviously the proposed biomaterials. In this study, the blood compatibility of the cryogels has been found to be fairly good. The possible explanation for the observed unusual fair blood compatibility may be the hydrophilic and biocompatible nature of the constituent PVA and chitosan. Alternatively, since only physical cross-linking is involved in the preparation of cryogels in the present study and no chemical cross-linking agent was used, the prepared cryogels obviously show excellent antithrombogenic property. The % hemolysis data indicate that it varies in the range 22.5�C44.3% only, which implies for a fair biocompatibility of the matrix. The prepared cryogels show excellent antibacterial properties, as evident from the photograph shown in the results section.

The results suggest that an increasing amount of savlon shows increasing effective antibacterial property against E.coli, and the largest zone of inhibition is seen with 7 mL of savlon added. The increasing number of freeze-thaw cycles significantly reduces the pore sizes of the cryogels. The reason for the observed shrinkage in pore size may be that increasing the number of freeze-thaw cycles results in building of larger areas of crystalline regions in the cryogel and enhanced intermolecular forces between the polymer chains of the matrix. Both of these factors result in shrinking of pore sizes of the cryogel matrix. Experimental Materials Polyvinyl alcohol (PVA) (98.6% hydrolyzed, Mol. Wt.

1x 105 Da) and chitosan were purchased from Merck and used without purification. The antibacterial liquid savlon was a combination of chlorohexadiene gluconate and cetrimede and purchased from Johnson Johnson. The rest of the chemicals were of analytical grade, and doubly distilled water was used throughout the experiments. Fabrication of savlon-loaded cryogels In order to design a polymer blend of PVA and chitosan containing savlon as an antibacterial liquid, a cyclic freeze-thaw method was followed. In a typical experimental protocol, 3g of PVA was dissolved in a calculated amount of hot water, and 0.75 g of chitosan was dissolved in 2% acetic acid separately. Then, the above two polymer solutions were mixed, and 5 mL of savlon was added to the polymer solution. The mixture was homogenized properly and kept in a Petri dish at -20��C for 24 h.

The frozen gel was thawed for 2 h at room temperature and again placed for freezing. In this way, these freezing-thawing cycles were repeated a number of times Carfilzomib so that the whole gel ultimately changed into a semi-transparent solid but soft mass. The prepared savlon-loaded cryogels were allowed to swell in water until equilibrium swelling, so that excess polymers and savlon were leached out. The cryogels were cut into circular discs of definite size and stored in air-tight polyethylene bags for further studies.