Protein A immobilization and HIgG adsorption onto porous/nonporous and swellable HEMA-incorporated polyEGDMA microspheres

Both non swellable and swellable poly(EGDMA/HEMA) microbeads were produced by suspension copolymerization. These microbeads were modified by immobiliz ation of a spacer-arm (hexamethylene diamine (HMDA)) and protein A. The opt imal values for modifications were as follows. sodium periodate concentrati on. 1.0 mg ml(-1); HMDA concentration, 4 mg ml(-1); and glutaraldehyde conc entration, 0.070 mu g ml(-1). Adsorption of protein A onto the plain and pe riodate oxidized poly(EGDMA/HEMA) microbeads were very close to each other, and were 0.01-0.02 mg protein A on the I-g Microbeads I and II, respective ly. Protein A immobilization on poly(EGDMA/HEMA) microbeads were studied at different temperatures, times, and pHs using single protein solution conta ining different amounts of proteins. The optimal values for immobilization were as follows: the initial protein A concentration, 0.1 mg ml(-1); temper ature, 25 degrees C; pH, 9.5; and immobilization time, 120 min. Incorporati on of protein A resulted in 1.420 and 1.825 mg protein A on the 1-g Microbe ads I and II, respectively. HIgG adsorption capacity on the protein A-incor porated poly(EGDMA/HEMA) microbeads is 27 and 35 mg HIgG g(-1) polymer for Microbeads I and II, respectively.