Diego Romao Gondim

Dye Ligand Epoxide Chitosan/Alginate: A Potential New Stationary Phase for Human IgG Purification

Cibacron Blue F3GA immobilized as ligand onto epoxide chitosan/alginate composite was prepared and evaluated for the purification of human immunoglobulin G (IgG) isolated from human serum by dye-ligand affinity chromatography. The effect of buffer pH on IgG adsorption, kinetic and isothern adsorption of high-purity IgG were studied by batch adsorption. The adsorption isotherm data were well fitted (using 25 mmol/L sodium phosphate buffer at pH 6.0) by the Langmuir–Freundlich model with a maximum adsorption capacity of 99 mg/g, apparent dissociation constant of 1.2 × 10−6 mol/L and n equal to 4.86. Fixed-bed experiments were performed using high-purity IgG, achieving a recovery rate of 53%. Human serum diluted ten times was also injected into the column. An enrichment of IgG in the elution fraction with traces of human serum albumin was observed. According to the study results, this material can be applied in the purification of human IgG under optimized conditions.

Influence of buffer solutions in the adsorption of human serum proteins onto layered double hydroxide

The adsorption of human immunoglobulin G (IgG) and human serum albumin (HSA) on a non-calcined Mg-Al layered double hydroxide (3:1 Mg-Al LDH) was studied in batch and fixed bed experiments, focusing on the effect of buffer solution and pH over sorbent uptake. Mg-Al LDH was synthesized and characterized by X-ray diffraction (XRD), N2 adsorption-desorption isotherms at -196°C, X-ray photoelectron spectroscopy (XPS), Zero point charge (pHzpc), particle size distribution and Fourier transform infra-red (FTIR). Batch adsorption experiments were performed in order to investigate the effects of pH on IgG and HSA adsorption with different buffers: sodium acetate (ACETATE), sodium phosphate (PHOSPHATE), 3-(N-morpholino) propanesulfonic acid (MOPS), 4-(2-Hydroxyethyl)piperazine-1-ethanesulfonic acid (HEPES) and trizma-hydrochloric acid (TRIS-HCl). Maximum adsorption capacities estimated by the Langmuir model were 239mgg-1 for IgG and 105mgg-1 for HSA in TRIS-HCl buffer. On the other hand, the highest selectivity for IgG adsorption over HSA was obtained with buffer PHOSPHATE (pH 6.5). The maximum IgG and HSA adsorption uptake in this case were 165 and 36mgg-1, respectively. Fixed bed experiments were carried out with both proteins using PHOSPHATE buffer (pH 6.5), which confirmed that IgG was more selectively adsorbed than HSA on Mg-Al LDH and both could be fully recovered by elution with sodium chloride (NaCl).