@article{gugliuzza_boi_2024, title={Editorial for the Special Issue "Preparation and Application of Advanced Functional Membranes"}, volume={14}, ISSN={["2077-0375"]}, DOI={10.3390/membranes14050100}, abstractNote={Membrane science is a discipline that cuts across almost all fields of research and experimentation [...].}, number={5}, journal={MEMBRANES}, author={Gugliuzza, Annarosa and Boi, Cristiana}, year={2024}, month={May} }
 @article{altern_kocot_lebarre_boi_phillips_roush_menegatti_cramer_2024, title={Mechanistic model-based characterization of size-exclusion-mixed-mode resins for removal of monoclonal antibody fragments}, volume={1718}, ISSN={["1873-3778"]}, DOI={10.1016/j.chroma.2024.464717}, abstractNote={Although antibody fragments are a critical impurity to remove from process streams, few platformable purification techniques have been developed to this end. In this work, a novel size-exclusion-mixed-mode (SEMM) resin was characterized with respect to its efficacy in mAb fragment removal. Inverse size-exclusion chromatography showed that the silica-based resin had a narrow pore size distribution and a median pore radius of roughly 6.2 nm. Model-based characterization was carried out with Chromatography Analysis and Design Toolkit (CADET), using the general rate model and the multicomponent Langmuir isotherm. Model parameters were obtained from fitting breakthrough curves, performed at multiple residence times, for a mixture of mAb, aggregates, and an array of fragments (varying in size). Accurate fits were obtained to the frontal chromatographic data across a range of residence times. Model validation was then performed with a scaled-up column, altering residence time and feed composition from the calibration run. Accurate predictions were obtained, thereby illustrating the model's interpolative and extrapolative capabilities. Additionally, the SEMM resin achieved 90% mAb yield, 37% aggregate removal, 29% F(ab′)2 removal, 54% Fab/Fc removal, 100% Fc fragments removal, and a productivity of 72.3 g mAbL×h. Model predictions for these statistics were all within 5%. Simulated batch uptake experiments showed that resin penetration depth was directly related to protein size, with the exception of the aggregate species, and that separation was governed by differential pore diffusion rates. Additional simulations were performed to characterize the dependence of fragment removal on column dimension, load density, and feed composition. Fragment removal was found to be highly dependent on column load density, where optimal purification was achieved below 100 mg protein/mL column. Furthermore, fragment removal was dependent on column volume (constant load mass), but agnostic to whether column length or diameter was changed. Lastly, the dependence on feed composition was shown to be complex. While fragment removal was inversely related to fragment mass fraction in the feed, the extent depended on fragment size. Overall, the results from this study illustrated the efficacy of the SEMM resin in fragment and aggregate removal and elucidated relationships with key operational parameters through model-based characterization.}, journal={JOURNAL OF CHROMATOGRAPHY A}, author={Altern, Scott H. and Kocot, Andrew J. and Lebarre, Jacob P. and Boi, Cristiana and Phillips, Michael W. and Roush, David J. and Menegatti, Stefano and Cramer, Steven M.}, year={2024}, month={Mar} }
 @article{lebarre_chu_altern_kocot_bhandari_barbieri_sly_crapanzano_cramer_phillips_et al._2024, title={Mixed-mode size-exclusion silica resin for polishing human antibodies in flow-through mode}, volume={1720}, ISSN={["1873-3778"]}, DOI={10.1016/j.chroma.2024.464772}, abstractNote={The polishing step in the downstream processing of therapeutic antibodies removes residual impurities from Protein A eluates. Among the various classes of impurities, antibody fragments are especially challenging to remove due to the broad biomolecular diversity generated by a multitude of fragmentation patterns. The current approach to fragment removal relies on ion exchange or mixed-mode adsorbents operated in bind-and-gradient-elution mode. However, fragments that bear strong similarity to the intact product or whose biophysical features deviate from the ensemble average can elude these adsorbents, and the lack of a chromatographic technology enabling robust antibody polishing is recognized as a major gap in downstream bioprocessing. Responding to this challenge, this study introduces size-exclusion mixed-mode (SEMM) silica resins as a novel chromatographic adsorbent for the capture of antibody fragments irrespective of their biomolecular features. The pore diameter of the silica beads features a narrow distribution and is selected to exclude monomeric antibodies, while allowing their fragments to access the pores where they are captured by the mixed-mode ligands. The static and dynamic binding capacity of the adsorbent ranged respectively between 30-45 and 25–33 gs of antibody fragments per liter of resin. Selected SEMM-silica resins also demonstrated the ability to capture antibody aggregates, which adsorb on the outer layer of the beads. Optimization of the SEMM-silica design and operation conditions – namely, pore size (10 nm) and ligand composition (quaternary amine and alkyl chain) as well as the linear velocity (100 cm/h), ionic strength (5.7 mS/cm), and pH (7) of the mobile phase – afforded a significant reduction of both fragments and aggregates, resulting into a final antibody yield up to 80% and monomeric purity above 97%.}, journal={JOURNAL OF CHROMATOGRAPHY A}, author={Lebarre, Jacob and Chu, Wenning and Altern, Scott and Kocot, Andrew and Bhandari, Dipendra and Barbieri, Eduardo and Sly, Jae and Crapanzano, Michael and Cramer, Steven and Phillips, Michael and et al.}, year={2024}, month={Apr} }
 @article{lavoie_fan_pourdeyhimi_boi_carbonell_2023, title={Advances in high-throughput, high-capacity nonwoven membranes for chromatography in downstream processing: A review}, volume={5}, ISSN={["1097-0290"]}, DOI={10.1002/bit.28457}, abstractNote={Abstract}, journal={BIOTECHNOLOGY AND BIOENGINEERING}, author={Lavoie, Joseph and Fan, Jinxin and Pourdeyhimi, Behnam and Boi, Cristiana and Carbonell, Ruben G.}, year={2023}, month={May} }
 @misc{overton_boi_shastry_smith-moore_balchunas_sambandan_gilleskie_2023, title={Development and Delivery of a Hands-On Short Course in Adeno-Associated Virus Manufacturing to Support Growing Workforce Needs in Gene Therapy}, volume={34}, ISSN={["1557-7422"]}, url={http://dx.doi.org/10.1089/hum.2022.235}, DOI={10.1089/hum.2022.235}, abstractNote={The manufacturing of gene therapy products is a rapidly growing industry bolstered by the tremendous potential of these therapies to provide lifesaving treatment for rare and complex genetic diseases. The industry's steep rise has resulted in a high demand for skilled staff required to manufacture gene therapy products of the expected high quality. To address this skill shortage, more opportunities for education and training in all aspects of gene therapy manufacturing are needed. The Biomanufacturing Training and Education Center (BTEC) at the North Carolina State University (NC State) has developed and delivered (and continues to deliver) a four-day, hands-on course titled Hands-On cGMP Biomanufacturing of Vectors for Gene Therapy. The course, which consists of 60% hands-on laboratory activities and 40% lectures, aims to provide a comprehensive understanding of the gene therapy production process, from vial thaw through the final formulation step, and analytical testing. This paper discusses the design of the course, the backgrounds of the nearly 80 students who have participated in the seven offerings held since March 2019, and feedback from the course participants.}, number={7-8}, journal={HUMAN GENE THERAPY}, publisher={Mary Ann Liebert Inc}, author={Overton, Laurie and Boi, Cristiana and Shastry, Shriarjun and Smith-Moore, Caroline and Balchunas, John and Sambandan, Deepa and Gilleskie, Gary}, year={2023}, month={Apr}, pages={259–272} }
 @article{sripada_elhanafi_collins_williams_linova_woodley_boi_menegatti_2023, title={Pseudo-affinity capture of <i>K. phaffii</i> host cell proteins in flow-through mode: Purification of protein therapeutics and proteomic study}, volume={326}, ISSN={["1873-3794"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85169830823&partnerID=MN8TOARS}, DOI={10.1016/j.seppur.2023.124777}, abstractNote={K. phaffii is a versatile expression system that is increasingly utilized to produce biological therapeutics – including enzymes, engineered antibodies, and gene-editing tools – that feature multiple subunits and complex post-translational modifications. Two major roadblocks limit the adoption of K. phaffii in industrial biomanufacturing: its proteome, while known, has not been linked to downstream process operations and detailed knowledge is missing on problematic host cell proteins (HCPs) that endanger patient safety or product stability. Furthermore, the purification toolbox has not evolved beyond the capture of monospecific antibodies, and few solutions are available for engineered antibody fragments and other protein therapeutics. To unlock the potential of yeast-based biopharmaceutical manufacturing, this study presents the development and performance validation of a novel adsorbent – PichiaGuard – functionalized with peptide ligands that target the whole spectrum of K. phaffii HCPs and designed for protein purification in flow-through mode. The PichiaGuard adsorbent features high HCP binding capacity (∼25 g per liter of resin) and successfully purified a monoclonal antibody and an ScFv fragment from clarified K. phaffii harvests, affording > 300-fold removal of HCPs and high product yields (70–80%). Notably, PichiaGuard outperformed commercial ion exchange and mixed-mode resins without salt gradients or optimization in removing high-risk HCPs – including aspartic proteases, ribosomal subunits, and other peptidases – thus demonstrating its value in modern biopharmaceutical processing.}, journal={SEPARATION AND PURIFICATION TECHNOLOGY}, author={Sripada, Sobhana A. and Elhanafi, Driss and Collins, Leonard B. and Williams, Taufika I. and Linova, Marina Y. and Woodley, John M. and Boi, Cristiana and Menegatti, Stefano}, year={2023}, month={Dec} }
 @article{fan_sripada_pham_linova_woodley_menegatti_boi_carbonell_2023, title={Purification of a monoclonal antibody using a novel high-capacity multimodal cation exchange nonwoven membrane}, volume={317}, ISSN={["1873-3794"]}, DOI={10.1016/j.seppur.2023.123920}, abstractNote={A high-capacity, multimodal cation exchange (MMC) chromatographic membrane was developed by conjugating a multimodal ligand – 2-mercaptopyridine-3-carboxylic acid (MPCA) – on a polybutylene terepthalate (PBT) nonwoven fabric. The membrane features an equilibrium binding capacity of ≈ 1000 mg of human polyclonal IgG (IgG) per g of membrane and dynamic binding capacities (DBC10%) ranging from 77.5 to 115.1 mg/mL (residence times of 1 and 5 min, respectively); these values are 2-to-3-fold higher than those of commercial MMC adsorbents. The effects of buffer composition, pH, conductivity on the binding behavior of the MMC-MPCA membrane were investigated in detail. As a moderate cation exchange binder, MPCA enables effective protein elution using buffers with mild pH (8.0–9.0) and conductivity (≈13 mS/cm), thus circumventing the harsh conditions often needed in multimodal chromatography. The MMC-MPCA membrane was evaluated for product capture in bind-and-elute mode on a Chinese hamster ovary (CHO) cell culture harvest containing therapeutic monoclonal antibodies, using commercial multimodal (Capto MMC and MX-Trp-650M) and affinity (AF-rProtein A HC-650F) resins as controls. The MMC-MPCA membrane outperformed the multimodal resins in terms of binding capacity as well as clearance of host cell proteins (HCPs) and aggregates. The membrane was then evaluated by polishing the mAb from a Protein A eluate in bind-and-elute mode. The MMC-MPCA membrane reduced the level of high molecular weight components from 11% to 4% and the HCP content from 1319.7 ppm to 48.7 ppm (LRV of 1.4). Most notably, proteomics analysis of the product demonstrated the clearance of a significant fraction of persistent, high-risk HCPs from the Protein A eluate.}, journal={SEPARATION AND PURIFICATION TECHNOLOGY}, author={Fan, Jinxin and Sripada, Sobhana A. and Pham, Dan N. and Linova, Marina Y. and Woodley, John M. and Menegatti, Stefano and Boi, Cristiana and Carbonell, Ruben G.}, year={2023}, month={Jul} }
 @article{boi_malavasi_carbonell_gilleskie_2022, title={A direct comparison between membrane adsorber and packed column chromatography performance (vol 1612, 460629, 2020)}, volume={1666}, ISSN={["1873-3778"]}, DOI={10.1016/j.chroma.2022.462852}, journal={JOURNAL OF CHROMATOGRAPHY A}, author={Boi, Cristiana and Malavasi, Andrea and Carbonell, Ruben G. and Gilleskie, Gary}, year={2022}, month={Mar} }
 @article{fan_barbieri_shastry_menegatti_boi_carbonell_2022, title={Purification of Adeno-Associated Virus (AAV) Serotype 2 from Spodoptera frugiperda (Sf9) Lysate by Chromatographic Nonwoven Membranes}, volume={12}, ISSN={["2077-0375"]}, DOI={10.3390/membranes12100944}, abstractNote={The success of adeno-associated virus (AAV)-based therapeutics in gene therapy poses the need for rapid and efficient processes that can support the growing clinical demand. Nonwoven membranes represent an ideal tool for the future of virus purification: owing to their small fiber diameters and high porosity, they can operate at high flowrates while allowing full access to target viral particles without diffusional limitations. This study describes the development of nonwoven ion-exchange membrane adsorbents for the purification of AAV2 from an Sf9 cell lysate. A strong anion-exchange (AEX) membrane was developed by UV grafting glycidyl methacrylate on a polybutylene terephthalate nonwoven followed by functionalization with triethylamine (TEA), resulting in a quaternary amine ligand (AEX-TEA membrane). When operated in bind-and-elute mode at a pH higher than the pI of the capsids, this membrane exhibited a high AAV2 binding capacity (9.6 × 1013 vp·mL−1) at the residence time of 1 min, and outperformed commercial cast membranes by isolating AAV2 from an Sf9 lysate with high productivity (2.4 × 1013 capsids·mL−1·min−1) and logarithmic reduction value of host cell proteins (HCP LRV ~ 1.8). An iminodiacetic acid cation-exchange nonwoven (CEX-IDA membrane) was also prepared and utilized at a pH lower than the pI of capsids to purify AAV2 in a bind-and-elute mode, affording high capsid recovery and impurity removal by eluting with a salt gradient. To further increase purity, the CEX-IDA and AEX-TEA membranes were utilized in series to purify the AAV2 from the Sf9 cell lysate. This membrane-based chromatography process also achieved excellent DNA clearance and a recovery of infectivity higher that that reported using ion-exchange resin chromatography.}, number={10}, journal={MEMBRANES}, author={Fan, Jinxin and Barbieri, Eduardo and Shastry, Shriarjun and Menegatti, Stefano and Boi, Cristiana and Carbonell, Ruben G.}, year={2022}, month={Oct} }
 @article{fan_boi_lemma_lavoie_carbonell_2021, title={Iminodiacetic Acid (IDA) Cation-Exchange Nonwoven Membranes for Efficient Capture of Antibodies and Antibody Fragments}, volume={11}, ISSN={["2077-0375"]}, DOI={10.3390/membranes11070530}, abstractNote={There is strong need to reduce the manufacturing costs and increase the downstream purification efficiency of high-value therapeutic monoclonal antibodies (mAbs). This paper explores the performance of a weak cation-exchange membrane based on the coupling of IDA to poly(butylene terephthalate) (PBT) nonwoven fabrics. Uniform and conformal layers of poly(glycidyl methacrylate) (GMA) were first grafted to the surface of the nonwovens. Then IDA was coupled to the polyGMA layers under optimized conditions, resulting in membranes with very high permeability and binding capacity. This resulted in IgG dynamic binding capacities at very short residence times (0.1–2.0 min) that are much higher than those achieved by the best cation-exchange resins. Similar results were obtained in the purification of a single-chain (scFv) antibody fragment. As is customary with membrane systems, the dynamic binding capacities did not change significantly over a wide range of residence times. Finally, the excellent separation efficiency and potential reusability of the membrane were confirmed by five consecutive cycles of mAb capture from its cell culture harvest. The present work provides significant evidence that this weak cation-exchange nonwoven fabric platform might be a suitable alternative to packed resin chromatography for low-cost, higher productivity manufacturing of therapeutic mAbs and antibody fragments.}, number={7}, journal={MEMBRANES}, author={Fan, Jinxin and Boi, Cristiana and Lemma, Solomon Mengistu and Lavoie, Joseph and Carbonell, Ruben G.}, year={2021}, month={Jul} }
 @article{lemma_boi_carbonell_2021, title={Nonwoven Ion-Exchange Membranes with High Protein Binding Capacity for Bioseparations}, volume={11}, ISSN={["2077-0375"]}, DOI={10.3390/membranes11030181}, abstractNote={This study presents the preparation and characterization of UV-grafted polybutylene terepthalate (PBT) ion exchange nonwoven membranes for chromatographic purification of biomolecules. The PBT nonwoven was functionalized with sulfonate and secondary amine for cation and anion exchange (CEX and AEX), respectively. The anion exchange membrane showed an equilibrium static binding capacity of 1300 mg BSA/g of membrane, while the cationic membranes achieved a maximum equilibrium binding capacity of over 700 mg hIgG/g of membrane. The CEX and AEX membranes resulted in dynamic binding capacities under flow conditions, with a residence time of 0.1 min, of 200 mg hIgG/mL of membrane and 55 mg BSA/mL of membrane, respectively. The selectivity of the PBT-CEX membranes was demonstrated by purifying antibodies and antibody fragments (hIgG and scFv) from CHO cell culture supernatants in a bind-an-elute mode. The purity of the eluted samples exceeded 97%, with good log removal values (LRV) for both host cell proteins (HCPs) and DNA. The PBT-AEX nonwoven membranes exhibited a DNA LRV of 2.6 from hIgG solutions in a flow-through mode with little loss of product. These results indicate that these membranes have significant potential for use in downstream purification of biologics.}, number={3}, journal={MEMBRANES}, author={Lemma, Solomon Mengistu I and Boi, Cristiana and Carbonell, Ruben G.}, year={2021}, month={Mar} }
 @article{boi_malavasi_carbonell_gilleskie_2020, title={A direct comparison between membrane adsorber and packed column chromatography performance}, volume={1612}, ISSN={["1873-3778"]}, DOI={10.1016/j.chroma.2019.460629}, abstractNote={The purpose of this work was to compare side by side the performance of packed bed and membrane chromatography adsorption processes for protein purification. The comparison was performed using anion exchange media with the same ligand immobilized on the adsorbing surface, namely the strong Q quaternary ammonium group, R-CH2-N+-(CH3)3, and bovine serum albumin (BSA) as a model protein. In addition, the stationary phase volume was held constant for each geometry (3 mL) and runs were executed using the same mobile phase superficial velocity. As expected, the packed bed column showed higher equilibrium binding of BSA at 66.9 mg/mL versus 43.04 mg/mL for the membrane adsorber. Dynamic binding capacities were also higher in the packed bed; for example, at 97.5 cm/h, a capacity of 62.8 mg/mL was measured for the packed bed versus 20.7 mg/mL for the membrane adsorber. The higher equilibrium and dynamic capacities of the packed bed are likely due to the higher surface area per unit volume of the resin. However, the maximum productivity for the membrane adsorber was 111 mg/(mL h), a value that was 3.3 times higher than the one of the packed column. The bed utilization - defined as the ratio of the dynamic binding capacity at 10% breakthrough to the saturation binding capacity - was also higher for the packed column at long residence times and lower at short residence times confirming the better performance of membrane chromatography at high flow rates.}, journal={JOURNAL OF CHROMATOGRAPHY A}, author={Boi, Cristiana and Malavasi, Andrea and Carbonell, Ruben G. and Gilleskie, Gary}, year={2020}, month={Feb} }