Polyacrylamide-alginate (PAAm-Alg) and phospho-L-tyrosine-linked PAAm-Alg monolithic cryogels: Purification of IgG from human serum

In recent decades cryogels as monolithic materials have gained interest as stationary phase in chromatography for purification of biomolecules. In this study, polyacrylamide-alginate (PAAm-Alg) monolithic cryogels were prepared by cryo-copolymerization of acrylamide and alginate monomers and methylene-bisacrylamide as crosslinker to be used as a matrix in affinity chromatography for purification of proteins. Ortho-phospho-Ltyrosine (P-Tyr) was covalently attached onto PAAm-Alg cryogels via bisoxirane-activation (PAAm-Alg-Bix-PTyr) and both derivatized and non-derivatized cryogels were utilized for the purification of immunoglobulin G (IgG) from human serum. Cryogels were characterized by scanning electron microscopy, swelling tests, elemental analysis, FTIR, and flow dynamics. The effects of buffer systems, conductivity, and pH on IgG adsorption were studied. Through breakthrough curve analysis a dynamic capacity of 9.2 mg IgG/mL with an IgG purity of 94% was obtained (based on ELISA analysis of IgG and albumin) for PAAm-Alg-Bix-P-Tyr cryogel when human serum was diluted in 10 mmol/L NaP buffer at pH 6.0. The adsorption isotherm data were well described by the Langmuir model with value of maximum adsorption capacity of 36.12 +/- 3.63 mg of IgG/g for PAAm-Alg-Bix-P-Tyr. The PAAm-Alg-Bix-P-Tyr cryogel provides an attractive alternative for adsorption of IgG from human serum.