Swelling properties of semi-IPN type hydrogels containing acrylamide-citraconic acid-chitosan and lipase release behaviors

In this study, semi-IPN hydrogels containing different compositions ofAcrylamide (AAm), Citraconic acid (SA) and Chitosan (K) weresynthesized by free radical polymerization using ammoniumpersulphate / sodium methabisulphite [(NH4)2S2O8 / Na2S2O5] as a radicalinitiator pair in the presence of ethyleneglycoldimethacrylate (EGDMA)as a crosslinker. Their swelling behavior was investigated as a functionof time, pH and temperature. The percentage swelling (S %) of allhydrogels were increased with time but after 15 hour constantpercentage swelling was observed. The presence of citraconic acid ingel matrix decreases the swelling percentages. KAAmSA-1 wasdetermined as the most swollen hydrogel at pH=7,4 and 37,0 ºC. Lipaseimmobilization is made via adsorbation, covalent binding to pointactivated with 1-cyclohexyl-3-(2-morpholino-ethyl) carbodiimide (CDI)and entrapment methods into KAAmSA-2 hydrogel getting the optimumconditions in semi-IPN type hydrogels. Hydrogels immobilized andentrapped lipase enzyme releasing has been followed by UVspectrophotometer. All of the release studies were carried out at pH=7,4and 37,0 ºC. When the release study was investigated, it has been seenthat lipase releasing of adsorbed hydrogel is too more than theactivated with (CDI) of immobilized hydrogel. When the release valueswere investigated, it has been seen that releasing of enzyme is around100%. The release of entrapped lipase kinetic data has found by makeusing from Fick law than k, n parameter were calculated 3,13 x 10-4 and1,36, respectively. Olive oil studies have been made for determinationof activity of lipase entrapped KAAmSA-2 hydrogel.