title: Agar-based magnetic affinity support for protein adsorption.
abstract: Magnetic colloidal particles were prepared by a coprecipitation method. The particles were composed of nanometer-sized superparamagnetic Fe(3)O(4) particles stabilized by lauric acid. Then, magnetic agar gel beads were produced by a water-in-oil emulsification method using a mixture of agar solution and the magnetic colloidal particles as the aqueous phase. A reactive triazine dye, Cibacron blue 3GA (CB), was coupled to the gel to prepare an agar-based magnetic affinity support (MAS) for protein adsorption. The support showed good magnetic responsiveness in a magnetic field. Bovine serum albumin (BSA) was used as a model protein to test adsorption equilibrium and kinetic behavior of the MAS. The adsorption equilibrium of BSA to the MAS was described by the Langmuir-type isotherm. Adsorption capacity of the MAS for BSA was up to 25 mg/mL at a CB coupling density of 1.6 micromol/mL. The effect of ionic strength on BSA adsorption was complex, exhibiting a maximum capacity at an ionic strength of 0.06 mol/L. The adsorption of BSA to the MAS was also influenced by pH. Uptake rate of BSA to the MAS was analyzed using a pore diffusion model. The pore diffusion coefficient was estimated to be 1.75 x 10(-11) m(2)/s. Finally, recycled use of the MAS demonstrated the stability of the MAS in protein adsorption and magnetic responsiveness.
authors.affiliation: Department of Biochemical Engineering, Tianjin University, Tianjin 300072, People's Republic of China.
authors.forename: X D
authors.initials: XD
authors.lastname: Tong
authors.forename: Y
authors.initials: Y
authors.lastname: Sun
mesh_terms: D000327:Adsorption; D000362:Agar; D003102:Colloids / Q000737:chemistry; D004396:Coloring Agents / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008280:Magnetics; D009994:Osmolar Concentration; D011506:Proteins / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry; D014227:Triazines / Q000737:chemistry
chemical_list: D003102:Colloids; D004396:Coloring Agents; D011506:Proteins; D014227:Triazines; D012710:Serum Albumin, Bovine; C012842:Cibacron Blue F 3GA; D000362:Agar