Purification of immunoglobulin G-based biopharmaceuticals using supported ionic liquids

• Autor(a) principal: Castro, Mariana Meireles e
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/37160
• topic: Biopharmaceuticals; Antibodies; Immunoglobulin G; Downstream processing; Solid-phase extraction; Supported Ionic Liquids

Antibodies are responsible for the humoral response and belong to the adaptive processes of the immune system. These properties distinguish antibodies, such as immunoglobulin G (IgG), as important proteins for scientific and clinical research, especially in the treatment of various diseases and in a variety of diagnostic tests. Thus, the production of therapeutic antibodies must be subject to strict criteria of efficiency and safety, which requires a high degree of purity. However, this process is associated with a high cost, due to the currently used downstream processing, which has been a major obstacle to the widespread application of antibodies. Therefore, the development of new cost-effective methods is crucial, where solid phase extraction has proven to be effective. Thus, in this work, resin-based supported ionic liquids (SILs) were investigated for the extraction and purification of IgG polyclonal antibodies, and the effect of the chemical structure of the ionic liquids (ILs), the operating conditions of extraction and purification were optimized to improve IgG yield and purity. In this dissertation, SILs ([MERR][C₁C₁im]Cl (1), ([MERR][C₁C₁im]Cl (2), and [MERR][N₁₈₈₈]Cl) were first synthesized and characterized. Then, a study was carried out with pure solutions of IgG and HSA to evaluate the adsorption capacity on SILs. For this assay, the best result in the adsorption of pure IgG was for Merrifield resin (pH 7, 75-fold dilution), with adsorption yield on the material of 96, 1%. Subsequently, the adsorption was studied in a binary mixture of IgG and HSA, with a purification value obtained of 1.77 for the IgG adsorbed on the material [MERR][C₁C₁im]Cl (1), at pH 4 and 50-fold dilution. Finally, the operational conditions for adsorption of IgG in human serum were studied and optimized, namely the effect of material synthesis, pH and concentration, type of buffer, two-step adsorption and solid-liquid ratio. As for this process, under the best conditions ([MERR][C₁C₁im]Cl (2) at pH 9, 20-fold dilution and S/L ratio of 100 mg.mL⁻¹) were obtained high purity values, 97.8% (purification factor of 3.56). With respect to the other SILs, a 2.75-fold purification (75% purity) was obtained for [MERR][C₁C₁im]Cl (1) at two-step adsorption, pH 5, 20-fold dilution and S/L ratio of 100 mg.mL⁻¹; and a 2.66-fold purification (60.8% purity) was obtained for [MERR][N₁₈₈₈]Cl at pH 7, 50-fold dilution and S/L ratio of 100 mg.mL⁻¹. In conclusion, the use of SILs was found to be promising and efficient in purifying IgG antibodies from human serum.