Synthesis of tentacle type magnetic beads as immobilized metal chelate affinity support for cytochrome c adsorption


TURKMEN D. , Yavuz H. , DENIZLI A.

INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES, cilt.38, ss.126-133, 2006 (SCI İndekslerine Giren Dergi) identifier identifier identifier

  • Cilt numarası: 38 Konu: 2
  • Basım Tarihi: 2006
  • Doi Numarası: 10.1016/j.ijbiomac.2006.01.018
  • Dergi Adı: INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
  • Sayfa Sayıları: ss.126-133

Özet

Magnetic poly(2-hydroxyethylmethacrylate) (mPHEMA) beads with an average diameter of 100-140 mu m were produced by suspension polymerization in the presence of magnetite particles (i.e. Fe3O4)- Specific surface area and average pore size of the magnetic beads was found to be 50m(2)/g and 819 mm, respectively. Ester groups in the mPHEMA structure were converted to imine groups by reacting with poly(ethyleneimine) (PEI) in the presence of NaH. Amino (-NH2) content of PEI-attached mPHEMA beads was determined as 102 mg PEI/g. Then, Cu2+ ions were chelated on the magnetic beads in the range of 20-793 mu mol Cu2+/g. Cytochrome c (cyt c) adsorption was performed on the metal chelating beads from aqueous solutions containing different amounts of cyt c at different pHs, Cu2+ loadings and temperatures. Cyt c adsorption on the mPHEMA/PEI beads was 4.6 mg/g. Cu2+ chelation increased the cyt c adsorption significantly (40.1 mg/g). Adsorption capacity increased with Cu2+ loading and then reached a saturation value. Cyt c adsorption decreased with increasing temperature. Cyt c molecules could be reversibly adsorbed and eluted ten times with the magnetic adsorbents without noticeable loss in their cyt c adsorption capacity. The applicability of two kinetic models including pseudo-first order and pseudo-second order model was estimated on the basis of comparative analysis of the corresponding rate parameters, equilibrium capacity and correlation coefficients. Results suggest that chemisorption processes could be the rate-limiting step in the adsorption process. In the last part of this article, cyt c adsorption experiments were performed in a magnetically stabilized fluidized bed (MSFB) system at optimum conditions determined from the batch experiments. The adsorption capacity decreased significantly from 46.8 to 15.4 mg/g polymer with the increase of the flow-rate from 0.5 to 4.0 ml/min. The resulting magnetic chelator beads possessed excellent long-term storage stability. (c) 2006 Elsevier B.V. All rights reserved.