Lentivirus capture directly from cell culture with Q-functionalised microcapillary film chromatography

Applications of microcapillary films in bioanalytical techniques

Microcapillary film (MCF) is an extruded plastic film with an array of parallel microcapillaries (30-500 μm) and it has wide potential applications in bioanalytical techniques as a microfluidic platform. With different surface modification strategies, an MCF combines the advantages of its structure and modified chemical properties to realize various bioanalytical functions. In this review, we begin by introducing the manufacturing process of MCFs, common materials used to produce MCFs, surface treatment approaches of inner surfaces, and a signal detection and readout system of the MCF platform. Then, we summarize some typical applications of MCFs, particularly in protein chromatography, Escherichia coli detection for urinary tract infections, prostate-specific antigen detection for prostate cancer and multiplex immunoassays. Finally, future perspectives of MCFs in bioanalytical techniques are discussed.

Advances in Lentivirus Purification

Lentiviral vectors (LVs) have been increasingly used as a tool for gene and cell therapies since they can stably integrate the genome in dividing and nondividing cells. LV production and purification processes have evolved substantially over the last decades. However, the increasing demands for higher quantities with more restrictive purity requirements are stimulating the development of novel materials and strategies to supply the market with LV in a cost-effective manner. A detailed review of each downstream process unit operation is performed, limitations, strengths, and potential outcomes being covered. Currently, the majority of large-scale LV manufacturing processes are still based on adherent cell culture, although it is known that the industry is migrating fast to suspension cultures. Regarding the purification strategy, it consists of batch chromatography and membrane technology. Nevertheless, new solutions are being created to improve the current production schemes and expand its clinical use.

Development of a disposable micro-capillary film grafted with peptide ligands for immunoadsorption

Traditional chromatographic techniques used in downstream processes of biomolecule manufacturing are often time-consuming and expensive. In this study, a cost-effective microporous micro-capillary film (MMCF) composed of ethylenevinyl alcohol (EVOH) was evaluated for its potential application in immunoadsorption with high process efficiency. A peptide ligand Ac-Phe-Tyr-His-Glu (Ac-FYHE) was immobilized on the inner surface of MMCF for selective binding of human immunoglobulin (hIgG). The porous structure and chemical properties of the prepared MMCF were confirmed by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). hIgG (2 mg/ml) adsorption studies demonstrated that the binding process followed a Langmuir isotherm with equilibrium adsorption capacities of 9.31 and 3.47 mg/ml adsorbent under static and dynamic conditions, respectively. Moreover, the membrane showed good flowrate tolerance when studied under flowrates of 0.5 ml/min to 10 ml/min. hIgG purity was 88.2% when obtained from an hIgG (2 mg/ml) and HSA (8 mg/ml) mixture and the purity remained over 80.0% when hIgG concentrations increased in the mixtures. Moreover, purity of 82.3% was achieved when removing hIgG directly from human serum. The MMCF-Ac-FYHE affinity column is expected to selectively remove hIgG from blood for the treatment of autoimmune diseases with high efficiency and cost effectiveness.

Functionalized micro-capillary film for the rapid at-line analysis of IgG aggregates in a cell culture bioreactor

A micro-capillary film has been developed that offers the potential for an at-line analytical tool for rapid aggregate analysis during biopharmaceutical antibody production. A non-porous walled micro-capillary film (NMCF) with cation exchange functionality was demonstrated to act as a chromatography medium that could be operated with high linear fluid velocities and was highly resistant to blockage by entrained particulates, including cells. The NMCF containing 19 parallel microcapillaries was prepared using a melt extrusion process from poly(ethylene-vinyl alcohol) copolymer (EVOH). The NMCF-EVOH was modified to have cation-exchange functionality (NMCF-EVOH-SP) and shown to differentially bind monomer and aggregated species of IgG antibody directly from a bioreactor. The use of NMCF-EVOH-SP to quantify aggregate concentrations in monoclonal antibody preparations in less than 20 minutes was demonstrated.

Optimised concentration and purification of retroviruses using membrane chromatography

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An in investigation in to the use of membrane chromatography for the purification of a γ-retrovirus was undertaken.

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The first report of a capacity for γ-retrovirus binding to a membrane chromatography device is presented.

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A process that produces a large increase in concentration and purity of the studied γ-retrovirus was identified.

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Proteomic techniques were used to identify the protein impurities removed and co-purified with the virus containing eluate.

The ability of an anion exchange membrane to purify a γ-retrovirus was assessed and optimised with respect to different loading and wash buffers. Recoveries of infectious virus greater than 50% were consistently obtained, while specific titre was increased up to one thousand fold when compared to the material loaded. Specific proteins removed and retained by this optimised process were identified by mass spectrometry. It was possible to successfully bind and elute the equivalent of 1.27 × 10⁸ Ifu/ml of ion exchange membrane. This could then be highly concentrated, with infectious virus concentrated to a maximum of 420-fold compared to the load.