Polyacrylamide-alginate (PAAm-Alg) and phospho-L-tyrosine-linked PAAm-Alg monolithic cryogels: Purification of IgG from human serum

Purification of Adeno-Associated Virus (AAV) Serotype 2 from Spodoptera frugiperda (Sf9) Lysate by Chromatographic Nonwoven Membranes

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.

Preparation of Molecularly Imprinted Poly(N-Isopropylacrylamide) Thermosensitive Based Cryogels

Cryogels are defined as polymeric gel matrices with interconnected macropores providing an advantage to be efficient carriers enabling unhindered diffusion of interested molecule. Cryogels could be easily prepared with the combination of molecular imprinting. Molecular imprinting technology provides selective and sensitive recognition for biomolecules. Immunoglobulin G (IgG) is a main effector component in human response. It is recently well recognized that the purification strategies for IgG have intensively gained attention to treat immune defects. Several methods including affinity chromatography have been applied for the purification of IgG from complex media. The purification of IgG plays a crucial role in medical applications using several materials. Among these, cryogels have been widely applied for the purification of several biomolecules. They offer to create low-cost affinity systems with high chemical and physical stability. Above all, temperature sensitive polymers enable a reversible phase transition against small temperature changes, by the way, reversible swelling and shrinking manner is observed.In this chapter, immunoglobulin G imprinted thermosensitive poly(N-isopropylacrylamide-N methacryloyl-(l)-histidine) [p(NIPA-MAH)/IgG-MIP] monolithic cryogel is explained. The preparation and characterization of cryogels are summarized. In addition, IgG binding studies with different parameters are briefly described. Herein, an effective design principle is presented to create imprinted temperature-sensitive cryogels for IgG purification. A p(NIPA-MAH)/IgG-MIP monolithic cryogel was synthesized for IgG purification. Afterward, IgG binding capacity of p(NIPA-MAH)/IgG-MIP cryogels was examined in different experimental conditions. Apart from these, selectivity of the p(NIPA-MAH)/IgG-MIP cryogel was shown by comparing IgG binding capacity of nonimprinted [p(NIPA-MAH)/NIP] one. Finally, the IgG purification ability of the p(NIPA-MAH)/IgG-MIP cryogel from human plasma was demonstrated proving its application in affinity chromatography using real sample.

Affinity monolith chromatography: A review of general principles and recent developments

Affinity monolith chromatography (AMC) is a liquid chromatographic technique that utilizes a monolithic support with a biological ligand or related binding agent to isolate, enrich, or detect a target analyte in a complex matrix. The target-specific interaction exhibited by the binding agents makes AMC attractive for the separation or detection of a wide range of compounds. This article will review the basic principles of AMC and recent developments in this field. The supports used in AMC will be discussed, including organic, inorganic, hybrid, carbohydrate, and cryogel monoliths. Schemes for attaching binding agents to these monoliths will be examined as well, such as covalent immobilization, biospecific adsorption, entrapment, molecular imprinting, and coordination methods. An overview will then be given of binding agents that have recently been used in AMC, along with their applications. These applications will include bioaffinity chromatography, immunoaffinity chromatography, immobilized metal-ion affinity chromatography, and dye-ligand or biomimetic affinity chromatography. The use of AMC in chiral separations and biointeraction studies will also be discussed.

Injectable Cryogels Associate with Adipose-Derived Stem Cells for Cardiac Healing After Acute Myocardial Infarctions

Treatment of adipose-derived stem cells (ADSCs) provides support for novel methods of conveying baseline cell protein endothelial cells to promote acute myocardial infarction in gelatin sericin (GS) lamin-coated antioxidant systems (GS@L). The ratio of fixity modules, pores, absorption, and inflammation in the range of ka (65 ka), 149 ±39.8 μm, 92.2%, 42 ± 1.38, and 29 ± 1.9 were observed in the synthesized frames for GS. Herein, ADSC-GS@L was prepared, and the relevant substance for the development of cardiac regenerative applications was stable and physically chemical. In vitro assessments of ADSC-GS@L injectable cryogels established the enhanced survival rates of the cell and improved pro- angiogenic factors as well as pro-inflammatory expression, confirming the favorable outcomes of fractional ejections, fibro-areas, and vessel densities with reduced infraction dimensions. The novel ADSC-injecting cryogel method could be useful for successful heart injury therapies during acute myocardial infarction. Additionally, the method could be useful for successful heart injury therapies during coronary heart disease.

Performance of phospho-L-tyrosine immobilized onto alginate/polyacrylamide-based cryogels: Effect of ligand coupling on human IgG adsorption and Fab fragments separation

The ortho-phospho-tyrosine (P-Tyr) pseudoaffinity ligand was immobilized via ether linkage onto polyacrylamide-alginate (PAAm-Alg)-epoxy cryogels prepared according to two different approaches in order to explore their performance in the immunoglobulin G (IgG) purification from human serum. In the first approach, the P-Tyr was attached to cryogel prepared by cryocopolymerization of acrylamide and alginate with allyl glycidyl ether (AGE) as functional comonomer, and methylenebisacrylamide and Ca(II) as crosslinkers, obtaining the PAAm-Alg-AGE-P-Tyr. In the second approach, the PAAm-Alg was synthesized under the same conditions, but without AGE, and the P-Tyr was coupled to epichlorohydrin (ECH)-activated cryogel, obtaining the PAAm-Alg-ECH-P-Tyr. Both pseudoaffinity cryogels were characterized by scanning electron microscopy, swelling tests, porosity, ligand density, and flow dynamics. The human IgG differently interacted with the PAAm-Alg-ECH-P-Tyr and PAAm-Alg-AGE-P-Tyr cryogels, depending on the pH and adsorption buffer system used. The selectivity analyzed by electrophoretic profiles was similar for both cryogels, but PAAm-Alg-ECH-P-Tyr achieved higher IgG adsorption capacity (dynamic capacity of 12.62 mg of IgG/mL of cryogel). The IgG purity assayed by ELISA was 95%. The maximum IgG adsorption capacity and dissociation constant of the PAAm-Alg-ECH-P-Tyr, determined by Langmuir isotherm, were found to be 91.75 mg IgG/g of dry cryogel and 4.60 × 10^-6 mol/L at pH 6.0 from aqueous solutions. The PAAm-Alg-AGE-P-Tyr showed potential to purify the Fab fragments from papain-digested human IgG solution at pH 7.0. Fab fragments were separated from Fc fragments (but with uncleaved IgG) in eluted fractions (analyzed by the Western blot technique), with yield of 82% and purity of 95% (determined by radial immunodiffusion).

Development of histidine-tagged cyclic peptide functionalized monolithic material for the affinity purification of antibodies in biological matrices

The rapidly increasing applications of monoclonal antibodies (mAbs) in therapy have necessitated the development of mAb production and purification technologies for both academic and industrial usage. Herein, a histidine-tagged cyclic peptide (HHHHHHGSGSGSDC*AWHLGELVWC*T, the disulfide-bonded cysteines of which are indicated by asterisks, named HT25-cyclopeptide) functionalized monolithic material was developed by the metal ion chelation-based approach. The resulting material possessed suitable affinity and peptide ligand density (13.8 mg peptide ligand per mL of material), good porosity (67.1 %), acceptable specific surface area (52.95 m²/g), and lots of macropores (4.13 μm). Moreover, excellent antibody-specific selectivity, comparable or even better binding capacity (for dried material, maximum static binding capacity and dynamic binding capacity are about 119.3 mg/g and 17.05 mg/g, respectively) for antibody compared to previously developed affinity materials, acceptable resistance to trypsin digestion, and negligible nonspecific protein adsorption, were also achieved on this novel monolithic material. Compared with the corresponding cyclic peptide-based sepharose material, milder elution conditions were employed for the HT25-cyclopeptide-based monolithic material, which could effectively prevent the aggregation and denaturation of the enriched antibodies. This novel material was then successfully applied to the affinity enrichment and purification of mAbs (including infliximab and rituximab) in different cell culture media or IgG in human serum.

Redefining the chemistry of super-macroporous materials: when dendritic molecules meet polymer cryogels

Dendritic cryogels modify the functionality and properties against conventional cryogels and improve the Immunoglobulin G (IgG) adsorption.