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Performance and characterization of a nanophased porous hydroxyapatite for protein chromatography
Author(s) -
Jungbauer Alois,
Hahn Rainer,
Deinhofer Karin,
Luo Ping
Publication year - 2004
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.20121
Subject(s) - porosity , particle size , chromatography , particle (ecology) , chemistry , ceramic , elution , diffusion , materials science , calcium , chemical engineering , composite material , oceanography , physics , organic chemistry , engineering , thermodynamics , geology
Nanophased porous hydroxyapatite beads with particle diameters of 25 μm and 30 μm intended for use in protein and biomolecule separation are characterized with respect to chromatographic characteristics. These particles were produced from a hydroxyapatite gel by a controlled spray process yielding microspheres containing hydroxyapatite nanocrystals. By calcification of the microspheres, nanophased porous hydroxyapatite beads were obtained. As a reference material, ceramic hydroxyapatite Types I and II with a particle diameter of 40 μm was chosen. SEM pictures show that the surface of the nanophased hydroxyapatite is very rough compared to ceramic hydroxyapatite Types I and Type II. The calcium‐to‐phosphorous ratio of this nanophased hydroxyapatite is 1.6, which is slightly below the theoretical ratio of 1.67 of pure hydroxyapatite. The porosity is greater than 60%. An IgG binding capacity of 60.7 mg/ml for Bio‐Rad Type I and 36.0 mg/ml for Type II, 42.0 mg/ml for the nanophased material with 25 μm and 19.7 mg/ml for the nanophased material with 30 μm were observed. The nanophased material with 30 μm had the lowest mass transfer resistancy as indicated by the dependency of the dynamic binding capacity on velocity. It is assumed that the mass transport properties are characterized by a low particle diffusion resistancy or by slight intraparticle convection. The material also showed high selectivity for IgG. When culture supernatant with 5% FCS containing 3 mg/ml was loaded, pure IgG could be eluted by linear gradient with increasing sodium phosphate concentration. This nanophased material comprises a novel stationary phase for IgG separation. © 2004 Wiley Periodicals, Inc.