@article{sripada_barbieri_shastry_wuestenhagen_aldinger_rammo_schulte_daniele_menegatti_2024, title={Multiangle Light Scattering as a Lentivirus Purification Process Analytical Technology}, volume={5}, ISSN={["1520-6882"]}, DOI={10.1021/acs.analchem.4c01209}, abstractNote={The limited biomolecular and functional stability of lentiviral vectors (LVVs) for cell therapy poses the need for analytical tools that can monitor their titers and activity throughout the various steps of expression and purification. In this study, we describe a rapid (25 min) and reproducible (coefficient of variance ∼0.5–2%) method that leverages size exclusion chromatography coupled with multiangle light scattering detection (SEC-MALS) to determine size, purity, and particle count of LVVs purified from bioreactor harvests. The SEC-MALS data were corroborated by orthogonal methods, namely, dynamic light scattering (DLS) and transmission electron microscopy. The method was also evaluated for robustness in the range of 2.78 × 105–2.67 × 107 particles per sample. Notably, MALS-based particle counts correlated with the titer of infectious LVVs measured via transduction assays (R2 = 0.77). Using a combination of SEC-MALS and DLS, we discerned the effects of purification parameters on LVV quality, such as the separation between heterogeneous LV, which can facilitate critical decision-making in the biomanufacturing of gene and cell therapies.}, journal={ANALYTICAL CHEMISTRY}, author={Sripada, Sobhana A. and Barbieri, Eduardo and Shastry, Shriarjun and Wuestenhagen, Elena and Aldinger, Annika and Rammo, Oliver and Schulte, Michael M. and Daniele, Michael and Menegatti, Stefano}, year={2024}, month={May} } @article{kilgore_moore_sripada_chu_shastry_barbieri_hu_tian_petersen_mohammadifar_et al._2024, title={Peptide ligands for the universal purification of exosomes by affinity chromatography}, volume={8}, ISSN={["1097-0290"]}, DOI={10.1002/bit.28821}, abstractNote={Abstract Exosomes are gaining prominence as vectors for drug delivery, vaccination, and regenerative medicine. Owing to their surface biochemistry, which reflects the parent cell membrane, these nanoscale biologics feature low immunogenicity, tunable tissue tropism, and the ability to carry a variety of payloads across biological barriers. The heterogeneity of exosomes' size and composition, however, makes their purification challenging. Traditional techniques, like ultracentrifugation and filtration, afford low product yield and purity, and jeopardizes particle integrity. Affinity chromatography represents an excellent avenue for exosome purification. Yet, current affinity media rely on antibody ligands whose selectivity grants high product purity, but mandates the customization of adsorbents for exosomes with different surface biochemistry while their binding strength imposes elution conditions that may harm product's activity. Addressing these issues, this study introduces the first peptide affinity ligands for the universal purification of exosomes from recombinant feedstocks. The peptides were designed to (1) possess promiscuous biorecognition of exosome markers, without binding process‐related contaminants and (2) elute the product under conditions that safeguard product stability. Selected ligands SNGFKKHI and TAHFKKKH demonstrated the ability to capture of exosomes secreted by 14 cell sources and purified exosomes derived from HEK293, PC3, MM1, U87, and COLO1 cells with yields of up to 80% and up‐to 50‐fold reduction of host cell proteins (HCPs) upon eluting with pH gradient from 7.4 to 10.5, recommended for exosome stability. SNGFKKHI‐Toyopearl resin was finally employed in a two‐step purification process to isolate exosomes from HEK293 cell fluids, affording a yield of 68% and reducing the titer of HCPs to 68 ng/mL. The biomolecular and morphological features of the isolated exosomes were confirmed by analytical chromatography, Western blot analysis, transmission electron microscopy, nanoparticle tracking analysis.}, journal={BIOTECHNOLOGY AND BIOENGINEERING}, author={Kilgore, Ryan E. and Moore, Brandyn D. and Sripada, Sobhana A. and Chu, Wenning and Shastry, Shriarjun and Barbieri, Eduardo and Hu, Shiqi and Tian, Weihua and Petersen, Heidi and Mohammadifar, Mohammad and et al.}, year={2024}, month={Aug} } @article{shastry_barbieri_minzoni_chu_johnson_stoops_pancorbo_gilleskie_ritola_crapanzano_et al._2024, title={Serotype-agnostic affinity purification of adeno-associated virus (AAV) via peptide-functionalized chromatographic resins}, volume={1734}, ISSN={["1873-3778"]}, url={https://doi.org/10.1016/j.chroma.2024.465320}, DOI={10.1016/j.chroma.2024.465320}, abstractNote={Adeno-associated viruses (AAVs) have emerged as a prominent family of vectors for gene delivery, providing therapeutic options to diseases once deemed incurable. At the same time, they necessitate efficient and affordable purification methods that can be platformed to serve all AAV serotypes. Current chromatographic tools, while affording high product purity, fail to bind certain serotypes, provide limited yield and lifetime, and impose harsh elution conditions that can compromise the vector's activity and safety. Addressing these challenges, this work demonstrates the application of new peptide ligands as the first serotype-agnostic technology for AAV purification by affinity chromatography. Our study reveals a pH-dependent affinity interaction: AAV2, AAV3, AAV6, AAV9, and AAVrh.10 are effectively captured at neutral pH, while binding AAV1, AAV5, AAV7, and AAV8 is stronger in a slightly acidic environment. The elution of bound AAVs was achieved using magnesium chloride at neutral pH for all serotypes, consistently affording capsid yields above 50% and genome yields above 80%, together with a >100-fold reduction in host cell proteins and nucleic acids. In particular, peptide ligand A10 exhibited remarkable binding capacity (> 10}, journal={JOURNAL OF CHROMATOGRAPHY A}, author={Shastry, Shriarjun and Barbieri, Eduardo and Minzoni, Arianna and Chu, Wenning and Johnson, Stephanie and Stoops, Mark and Pancorbo, Jennifer and Gilleskie, Gary and Ritola, Kimberly and Crapanzano, Michael S. and et al.}, year={2024}, month={Oct} } @article{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={1043-0342 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{chu_shastry_barbieri_prodromou_greback-clarke_smith_moore_kilgore_cummings_pancorbo_et al._2023, title={Peptide ligands for the affinity purification of adeno-associated viruses from HEK 293 cell lysates}, volume={7}, ISSN={["1097-0290"]}, DOI={10.1002/bit.28495}, abstractNote={AbstractAdeno‐associated viruses (AAVs) are the vector of choice for delivering gene therapies that can cure inherited and acquired diseases. Clinical research on various AAV serotypes significantly increased in recent years alongside regulatory approvals of AAV‐based therapies. The current AAV purification platform hinges on the capture step, for which several affinity resins are commercially available. These adsorbents rely on protein ligands—typically camelid antibodies—that provide high binding capacity and selectivity, but suffer from low biochemical stability and high cost, and impose harsh elution conditions (pH < 3) that can harm the transduction activity of recovered AAVs. Addressing these challenges, this study introduces peptide ligands that selectively capture AAVs and release them under mild conditions (pH = 6.0). The peptide sequences were identified by screening a focused library and modeled in silico against AAV serotypes 2 and 9 (AAV2 and AAV9) to select candidate ligands that target homologous sites at the interface of the VP1‐VP2 and VP2‐VP3 virion proteins with mild binding strength (KD ~ 10−5–10−6 M). Selected peptides were conjugated to Toyopearl resin and evaluated via binding studies against AAV2 and AAV9, demonstrating the ability to target both serotypes with values of dynamic binding capacity (DBC10% > 1013 vp/mL of resin) and product yields (~50%–80%) on par with commercial adsorbents. The peptide‐based adsorbents were finally utilized to purify AAV2 from a HEK 293 cell lysate, affording high recovery (50%–80%), 80‐ to 400‐fold reduction of host cell proteins (HCPs), and high transduction activity (up to 80%) of the purified viruses.}, journal={BIOTECHNOLOGY AND BIOENGINEERING}, author={Chu, Wenning and Shastry, Shriarjun and Barbieri, Eduardo and Prodromou, Raphael and Greback-Clarke, Paul and Smith, Will and Moore, Brandyn and Kilgore, Ryan and Cummings, Christopher and Pancorbo, Jennifer and et al.}, year={2023}, month={Jul} } @article{barbieri_mollica_moore_sripada_shastry_kilgore_loudermilk_whitacre_kilgour_wuestenhagen_et al._2024, title={Peptide ligands targeting the vesicular stomatitis virus G (VSV-G) protein for the affinity purification of lentivirus particles}, volume={121}, ISSN={["1097-0290"]}, DOI={10.1002/bit.28594}, abstractNote={AbstractThe recent uptick in the approval of ex vivo cell therapies highlights the relevance of lentivirus (LV) as an enabling viral vector of modern medicine. As labile biologics, however, LVs pose critical challenges to industrial biomanufacturing. In particular, LV purification—currently reliant on filtration and anion‐exchange or size‐exclusion chromatography—suffers from long process times and low yield of transducing particles, which translate into high waiting time and cost to patients. Seeking to improve LV downstream processing, this study introduces peptides targeting the enveloped protein Vesicular stomatitis virus G (VSV‐G) to serve as affinity ligands for the chromatographic purification of LV particles. An ensemble of candidate ligands was initially discovered by implementing a dual‐fluorescence screening technology and a targeted in silico approach designed to identify sequences with high selectivity and tunable affinity. The selected peptides were conjugated on Poros resin and their LV binding‐and‐release performance was optimized by adjusting the flow rate, composition, and pH of the chromatographic buffers. Ligands GKEAAFAA and SRAFVGDADRD were selected for their high product yield (50%–60% of viral genomes; 40%–50% of HT1080 cell‐transducing particles) upon elution in PIPES buffer with 0.65 M NaCl at pH 7.4. The peptide‐based adsorbents also presented remarkable values of binding capacity (up to 3·109 TU per mL of resin, or 5·1011 vp per mL of resin, at the residence time of 1 min) and clearance of host cell proteins (up to a 220‐fold reduction of HEK293 HCPs). Additionally, GKEAAFAA demonstrated high resistance to caustic cleaning‐in‐place (0.5 M NaOH, 30 min) with no observable loss in product yield and quality.}, number={2}, journal={BIOTECHNOLOGY AND BIOENGINEERING}, author={Barbieri, Eduardo and Mollica, Gina N. and Moore, Brandyn D. and Sripada, Sobhana A. and Shastry, Shriarjun and Kilgore, Ryan E. and Loudermilk, Casee M. and Whitacre, Zachary H. and Kilgour, Katie M. and Wuestenhagen, Elena and et al.}, year={2024}, month={Feb}, pages={618–639} } @article{shastry_chu_barbieri_greback-clarke_smith_cummings_minzoni_pancorbo_gilleskie_ritola_et al._2023, title={Rational design and experimental evaluation of peptide ligands for the purification of adeno-associated viruses via affinity chromatography}, volume={9}, ISSN={["1860-7314"]}, DOI={10.1002/biot.202300230}, abstractNote={AbstractAdeno‐associated viruses (AAVs) have acquired a central role in modern medicine as delivery agents for gene therapies targeting rare diseases. While new AAVs with improved tissue targeting, potency, and safety are being introduced, their biomanufacturing technology is lagging. In particular, the AAV purification pipeline hinges on protein ligands for the affinity‐based capture step. While featuring excellent AAV binding capacity and selectivity, these ligands require strong acid (pH <3) elution conditions, which can compromise the product's activity and stability. Additionally, their high cost and limited lifetime has a significant impact on the price tag of AAV‐based therapies. Seeking to introduce a more robust and affordable affinity technology, this study introduces a cohort of peptide ligands that (i) mimic the biorecognition activity of the AAV receptor (AAVR) and anti‐AAV antibody A20, (ii) enable product elution under near‐physiological conditions (pH 6.0), and (iii) grant extended reusability by withstanding multiple regenerations. A20‐mimetic CYIHFSGYTNYNPSLKSC and AAVR‐mimetic CVIDGSQSTDDDKIC demonstrated excellent capture of serotypes belonging to distinct clones/clades – namely, AAV1, AAV2, AAV5, AAV6, AAV8, and AAV9. This corroborates the in silico models documenting their ability to target regions of the viral capsid that are conserved across all serotypes. CVIDGSQSTDDDKIC‐Toyopearl resin features binding capacity (≈1014 vp mL−1) and product yields (≈60%–80%) on par with commercial adsorbents, and purifies AAV2 from HEK293 and Sf9 cell lysates with high recovery (up to 78%), reduction of host cell proteins (up to 700‐fold), and high transduction activity (up to 65%).}, journal={BIOTECHNOLOGY JOURNAL}, author={Shastry, Shriarjun and Chu, Wenning and Barbieri, Eduardo and Greback-Clarke, Paul and Smith, William K. and Cummings, Christopher and Minzoni, Arianna and Pancorbo, Jennifer and Gilleskie, Gary and Ritola, Kimberly and et al.}, year={2023}, month={Sep} } @article{kilgore_minzoni_shastry_smith_barbieri_wu_lebarre_chu_o'brien_menegatti_2023, title={The downstream bioprocess toolbox for therapeutic viral vectors}, volume={1709}, ISSN={["1873-3778"]}, DOI={10.1016/j.chroma.2023.464337}, abstractNote={Viral vectors are poised to acquire a prominent position in modern medicine and biotechnology owing to their role as delivery agents for gene therapies, oncolytic agents, vaccine platforms, and a gateway to engineer cell therapies as well as plants and animals for sustainable agriculture. The success of viral vectors will critically depend on the availability of flexible and affordable biomanufacturing strategies that can meet the growing demand by clinics and biotech companies worldwide. In this context, a key role will be played by downstream process technology: while initially adapted from protein purification media, the purification toolbox for viral vectors is currently undergoing a rapid expansion to fit the unique biomolecular characteristics of these products. Innovation efforts are articulated on two fronts, namely (i) the discovery of affinity ligands that target adeno-associated virus, lentivirus, adenovirus, etc.; (ii) the development of adsorbents with innovative morphologies, such as membranes and 3D printed monoliths, that fit the size of viral vectors. Complementing these efforts are the design of novel process layouts that capitalize on novel ligands and adsorbents to ensure high yield and purity of the product while safeguarding its therapeutic efficacy and safety; and a growing panel of analytical methods that monitor the complex array of critical quality attributes of viral vectors and correlate them to the purification strategies. To help explore this complex and evolving environment, this study presents a comprehensive overview of the downstream bioprocess toolbox for viral vectors established in the last decade, and discusses present efforts and future directions contributing to the success of this promising class of biological medicines.}, journal={JOURNAL OF CHROMATOGRAPHY A}, author={Kilgore, Ryan and Minzoni, Arianna and Shastry, Shriarjun and Smith, Will and Barbieri, Eduardo and Wu, Yuxuan and Lebarre, Jacob P. and Chu, Wenning and O'Brien, Juliana and Menegatti, Stefano}, year={2023}, month={Oct} } @article{wang_hosseini_shastry_barbieri_chu_menegatti_daniele_2023, title={Toward the quantification of adeno-associated virus titer by electrochemical impedance spectroscopy}, DOI={10.1109/BioSensors58001.2023.10281105}, abstractNote={Gene therapies have shown great promise for the potential treatment of a broad range of diseases. Adeno-associated viruses (AAVs) are popular gene vectors because of their ability to target specific tissues, and they have demonstrated high transduction efficiencies in multiple neurological targets. While these therapeutics hold great promise, their biomanufacturing has limited potential cost-reduction and more widespread adoption. Herein, we report the preliminary development of an immunosensor for measuring the titer of adeno-associated virus 2 (AAV2), which may be deployed for rapid quantification of product yield during AAV biomanufacturing. We functionalized an interdigitated electrode array with anti-AAV2 antibodies, and electrochemical impedance spectroscopy was employed to investigate the response to AAV2 titer. A Faradaic sensing principle was utilized, in which the charge transfer resistance (Rct) of an electrochemical reporter was monitored after capture of AAV2 on the surface of the sensor. A linear response was measured over titers 1012 - 1013 capsids/mL.}, journal={2023 IEEE BIOSENSORS CONFERENCE, BIOSENSORS}, author={Wang, Junhyeong and Hosseini, Mahshid and Shastry, Shriarjun and Barbieri, Eduardo and Chu, Wenning and Menegatti, Stefano and Daniele, Michael A.}, year={2023} } @article{chu_prodromou_moore_elhanafi_kilgore_shastry_menegatti_2022, title={Development of peptide ligands for the purification of a-1 antitrypsin from cell culture fluids}, volume={1679}, ISSN={["1873-3778"]}, DOI={10.1016/j.chroma.2022.463363}, abstractNote={α-1 antitrypsin (AAT) deficiency, a major risk factor for chronic obstructive pulmonary disease, is one of the most prevalent and fatal hereditary diseases. The rising demand of AAT poses a defined need for new processes of AAT manufacturing from recombinant sources. Commercial affinity adsorbents for AAT purification present the intrinsic limitations of protein ligands – chiefly, the high cost and the lability towards the proteases in the feedstocks and the cleaning-in-place utilized in biomanufacturing – which limit their application despite their high capacity and selectivity. This work presents the development of small peptide affinity ligands for the purification of AAT from Chinese hamster ovary (CHO) cell culture harvests. An ensemble of ligand candidates identified via library screening were conjugated on Toyopearl resin and evaluated via experimental and in silico AAT-binding studies. Initial ranking based on equilibrium binding capacity indicated WHAKKSKFG- (12.9 mg of AAT per mL of resin), WHAKKSHFG- (16.3 mg/mL), and KWKHSHKWG- (15.8 mg/mL) Toyopearl resins as top performing adsorbents. Notably, the fitting of adsorption data to Langmuir isotherms concurred with molecular docking and dynamics in returning values of dissociation constant (KD) between 1 – 10 µM. These peptide-based adsorbents were thus selected for AAT purification from CHO fluids, affording values of AAT binding capacity up to 13 gram per liter of resin, and product yield and purity up to 77% and 97%. WHAKKSHFG-Toyopearl resin maintained its purification activity upon 20 consecutive uses, demonstrating its potential for AAT manufacturing from recombinant sources.}, journal={JOURNAL OF CHROMATOGRAPHY A}, author={Chu, Wenning and Prodromou, Raphael and Moore, Brandyn and Elhanafi, Driss and Kilgore, Ryan and Shastry, Shriarjun and Menegatti, Stefano}, year={2022}, month={Aug} } @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}, url={http://dx.doi.org/10.3390/membranes12100944}, 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}, publisher={MDPI AG}, author={Fan, Jinxin and Barbieri, Eduardo and Shastry, Shriarjun and Menegatti, Stefano and Boi, Cristiana and Carbonell, Ruben G.}, year={2022}, month={Sep}, pages={944} }