Browsing by Author "Yavuz, Handan"
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Item Immobilization of alpha-amylase on Cu2+ chelated poly(ethylene glycol dimethacrylate-n-vinyl imidazole) matrix via adsorption(Elsevier, 2005) Yavuz, Handan; Denizli, Adil; Kara, Ali; Osman, Bilgen; Beşirli, Necati; Uludağ Üniversitesi/Fen Edebiyat Fakültesi/Kimya Bölümü.Poly(ethylene glycol dimethacrylate-n-vinyl imidazole) [poly(EGDMA-VIM)] hydrogel (average diameter 150-200 pm) was prepared by copolymerizing ethylene glycol dimethacrylate (EGDMA) with n-vinyl imidazole (VIM). The copolymer hydrogel bead composition was characterized by elemental analysis and found to contain 5 EGDMA monomer units each VIM monomer unit. Poly(EGDMA-VIM) beads had a specific surface area of 59.8 m(2)/g. Poly- (EGDMA-VIM) beads were characterized by swelling studies and SEM. Cu2+ ions were chelated on the poly(EGDMA-VIM) beads, then these beads were used in the adsorption of alpha-amylase from Aspergillus Oryzae in batch system. The maximum alpha-amylase adsorption capacity of the poly(EGDMA-VIM)-Cu2+ beads was observed as 38.9 mg/g at pH 4.0. The K-m values for immobilized alpha-amylase (poly(EGDMA-VIM)-Cu2+) (22.5 mM) was higher than that of free enzyme (15.8 mM). Storage stability was found to increase with immobilization. It was observed that enzyme could be repeatedly adsorbed and desorbed without significant loss in adsorption capacity or enzyme activity.Item Poly(hydroxyethyl methacrylate) based affinity membranes for in vitro removal of anti-dsDNA antibodies from SLE plasma(Elsevier, 2010-07-01) Uzun, Lokman; Yavuz, Handan; Çelik, Hamdi; Denizli, Adil; Osman, Bilgen; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Bölümü.; ABF-4791-2020; 15221651200The preparation of polymeric membrane using affinity technology for application in blood filtration devices is described here. DNA attached poly( hydroxyethyl methacrylate) (PHEMA) based microporous affinity membrane was prepared for selective removal of anti-dsDNA antibodies from systemic lupus erythematosus (SLE) patient plasma in in vitro. In order to further increase blood-compatibility of affinity membrane, aminoacid based comonomer N-methacryloyl-L-alanine (MAAL) was included in the polymerization recipe. PHEMAAL membrane was produced by a photopolymerization technique and then characterized by swelling tests and scanning electron microscope (SEM) studies. Blood-compatibility tests were also performed. The water swelling ratio of PHEMAAL membrane increased significantly (133.2%) compared with PHEMA (58%). PHEMAAL membrane has large pores around in the range of 5-10 mu m. All the clotting times increased when compared with PHEMA membrane. Loss of platelets and leukocytes was very low. DNA loading was 7.8 mg/g. There was a very low anti-dsDNA-antibody adsorption onto the plain PHEMAAL membrane, about 78 IU/g. The PHEMAAL-DNA membrane adsorbed anti-dsDNA-antibody in the range of 10-68 x 10(3) IU/g from SLE plasma. Anti-dsDNA-antibody concentration decreased significantly from 875 to 144 IU/ml with the time. Anti-dsDNA-antibodies could be repeatedly adsorbed and eluted without noticeable loss in the anti-dsDNA-antibody adsorption amount.