Fouling Resistant Membranes for the Separation of Protein Conjugates from Small Molecules
Mateo, Maximo
2023
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In 2021, 1.9 million people were diagnosed with cancer and 608,578 deaths were reported in the United States. Antibody-drug conjugates are a new technology promising an alternative for treating these diseases. Antibody-drug conjugates (ADCs) are complex structures consisting of antibodies covalently bonded to small-molecule drugs, combining the specificity of antibodies and the potency of small ... read moredrugs. However, the cost of ADC therapy can be expensive for working-class Americans. Thus, focusing on the cost associated with the downstream processing can help alleviate the total cost of manufacturing, reducing the cost of ADC therapy. In a simplified version, ADCs are produced by reacting the cytoxin drug with a monoclonal antibody. To separate the newly conjugated protein from the excess cytoxin drug, various methods need to be employed. Current purification methods involve size exclusion chromatography, hydrophobic interaction chromatography, and tangential flow filtration. However, the nonspecific adsorption of protein to the surface membrane and/or chromatography resin surfaces leads to the loss of the newly conjugated protein during this purification process. This thesis aims to test new ultrafiltration (UF) membranes prepared with zwitterionic surface-segregating additives for the bioseparation of ADCs during downstream processing and determine if their fouling resistance enables the purification of a model ADC with improved yield. To do this, polymerics ultrafiltration (UF) membranes were prepared from blends of varying amounts of zwitterionic surface-segregating copolymer (PMMA-r-MPC) with poly(vinylidene fluoride) (PVDF), a commodity polymer commonly used for making membranes. Their water permeance and selectivity were characterized using filtration experiments, and membranes prepared using 2% zwitterionic copolymer were selected for future study, and its resistance to fouling was demonstrated in protein filtration experiments. Then, a model system mimicking ADCs was designed, consisting of bovine γ-globulin (BGG) as a representative antibody and fluorescein (or fluorescein isothiocyanate), a dye, to represent the small molecule drug. The zwitterionic membranes exhibited full rejection of BGG while allowing the passage of fluorescein or unreacted fluorescein isothiocyanate, demonstrating their ability to successfully perform this separation. The fouling resistant properties of these membranes enabled them to sustain higher fluxes and achieve yields higher than the current downstream separation protocol.
Thesis (B.S.C.H.E.)--Tufts University, 2023.
Submitted to the Dept. of Chemical and Biological Engineering.read less - ID:
- 7s75dt67n
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