An ultra scale-down analysis of the recovery by dead-end centrifugation of human cells for therapy

Human leucocytes processed by fast-rate inertial microfluidics retain conventional functional characteristics

The manufacturing of clinical cellular therapies is a complex process frequently requiring manipulation of cells, exchange of buffers and volume reduction. Current manufacturing processes rely on either low throughput open centrifugation-based devices, or expensive closed-process alternatives. Inertial focusing (IF) microfluidic devices offer the potential for high-throughput, inexpensive equipment which can be integrated into a closed system, but to date no IF devices have been approved for use in cell therapy manufacturing, and there is limited evidence for the effects that IF processing has on human cells. The IF device described in this study was designed to simultaneously separate leucocytes, perform buffer exchange and provide a volume reduction to the cell suspension, using high flow rates with high Reynolds numbers. The performance and effects of the IF device were characterized using peripheral blood mononuclear cells and isolated monocytes. Post-processing cell effects were investigated using multi-parameter flow cytometry to track cell viability, functional changes and fate. The IF device was highly efficient at separating CD14+ monocytes (approx. 97% to one outlet, approx. 60% buffer exchange, 15 ml min-1) and leucocyte processing was well tolerated with no significant differences in downstream viability, immunophenotype or metabolic activity when compared with leucocytes processed with conventional processing techniques. This detailed approach provides robust evidence that IF devices could offer significant benefits to clinical cell therapy manufacture.

Assessment of the LOVO device for final harvest of novel cell therapies: a Production Assistance for Cellular Therapies multi-center study

BACKGROUND AIMS

The final harvest or wash of a cell therapy product is an important step in manufacturing, as viable cell recovery is critical to the overall success of a cell therapy. Most harvest/wash approaches in the clinical lab involve centrifugation, which can lead to loss of cells and decreased viability of the final product. Here the authors report on a multi-center assessment of the LOVO Cell Processing System (Fresenius Kabi, Bad Homburg, Germany), a cell processing device that uses a spinning filtration membrane instead of centrifugation.

METHODS

Four National Institutes of Health Production Assistance for Cellular Therapies cell processing facilities (CPFs) assessed the LOVO Cell Processing System for final harvest and/or wash of the following three different cell products: activated T cells (ATCs), tumor-infiltrating lymphocytes (TILs) and bone marrow-derived mesenchymal stromal cells (MSCs). Each site compared their current in-house, routinely used method of final cell harvest and/or wash with that of the LOVO device.

RESULTS

Final harvest and/or wash of ATCs, TILs and MSCs using the LOVO system resulted in satisfactory cell viability and recovery with some substantial improvement over the in-house methods of CPFs. Processing time was variable among cell types/facilities.

CONCLUSIONS

The LOVO Cell Processing System provides an alternative to centrifuge-based technologies. The system employs a spinning membrane filter, exposing cells to minimal g-forces compared with centrifugation, and is automated and closed. This small multi-center study demonstrated the ability of the LOVO device to yield satisfactory cell viability and recovery of T cells and MSCs.

Affinity Sedimentation and Magnetic Separation With Plant-Made Immunosorbent Nanoparticles for Therapeutic Protein Purification

The virus-based immunosorbent nanoparticle is a nascent technology being developed to serve as a simple and efficacious agent in biosensing and therapeutic antibody purification. There has been particular emphasis on the use of plant virions as immunosorbent nanoparticle chassis for their diverse morphologies and accessible, high yield manufacturing via plant cultivation. To date, studies in this area have focused on proof-of-concept immunosorbent functionality in biosensing and purification contexts. Here we consolidate a previously reported pro-vector system into a single Agrobacterium tumefaciens vector to investigate and expand the utility of virus-based immunosorbent nanoparticle technology for therapeutic protein purification. We demonstrate the use of this technology for Fc-fusion protein purification, characterize key nanomaterial properties including binding capacity, stability, reusability, and particle integrity, and present an optimized processing scheme with reduced complexity and increased purity. Furthermore, we present a coupling of virus-based immunosorbent nanoparticles with magnetic particles as a strategy to overcome limitations of the immunosorbent nanoparticle sedimentation-based affinity capture methodology. We report magnetic separation results which exceed the binding capacity reported for current industry standards by an order of magnitude.

Fluorescence Labeling of Circulating Tumor Cells with a Folate Receptor-Targeted Molecular Probe for Diffuse In Vivo Flow Cytometry

PURPOSE

We recently developed a new instrument called "diffuse in vivo flow cytometry" (DiFC) for enumeration of rare fluorescently labeled circulating tumor cells (CTCs) in small animals without drawing blood samples. Until now, we have used cell lines that express fluorescent proteins or were pre-labeled with a fluorescent dye ex vivo. In this work, we investigated the use of a folate receptor (FR)-targeted fluorescence molecular probe for in vivo labeling of FR+ CTCs for DiFC.

PROCEDURES

We used EC-17, a FITC-folic acid conjugate that has been used in clinical trials for fluorescence-guided surgery. We studied the affinity of EC-17 for FR+ L1210A and KB cancer cells. We also tested FR- MM.1S cells. We tested the labeling specificity in cells in culture in vitro and in whole blood. We also studied the detectability of labeled cells in mice in vivo with DiFC.

RESULTS

EC-17 showed a high affinity for FR+ L1210A and KB cells in vitro. In whole blood, 85.4 % of L1210A and 80.9 % of KB cells were labeled above non-specific background with EC-17, and negligible binding to FR- MM.1S cells was observed. In addition, EC-17-labeled CTCs were readily detectable in circulation in mice with DiFC.

CONCLUSIONS

This work demonstrates the feasibility of labeling CTCs with a cell-surface receptor-targeted probe for DiFC, greatly expanding the potential utility of the method for pre-clinical animal models. Because DiFC uses diffuse light, this method could be also used to enumerate CTCs in larger animal models and potentially even in humans.

Capture and metabolomic analysis of the human endometrial epithelial organoid secretome

Suboptimal uterine fluid (UF) composition can lead to pregnancy loss and likely contributes to offspring susceptibility to chronic adult-onset disorders. However, our understanding of the biochemical composition and mechanisms underpinning UF formation and regulation remain elusive, particularly in humans. To address this challenge, we developed a high-throughput method for intraorganoid fluid (IOF) isolation from human endometrial epithelial organoids. The IOF is biochemically distinct to the extraorganoid fluid (EOF) and cell culture medium as evidenced by the exclusive presence of 17 metabolites in IOF. Similarly, 69 metabolites were unique to EOF, showing asymmetrical apical and basolateral secretion by the in vitro endometrial epithelium, in a manner resembling that observed in vivo. Contrasting the quantitative metabolomic profiles of IOF and EOF revealed donor-specific biochemical signatures of organoids. Subsequent RNA sequencing of these organoids from which IOF and EOF were derived established the capacity to readily perform organoid multiomics in tandem, and suggests that transcriptomic regulation underpins the observed secretory asymmetry. In summary, these data provided by modeling uterine luminal and basolateral fluid formation in vitro offer scope to better understand UF composition and regulation with potential impacts on female fertility and offspring well-being.

Two-level submicron high porosity membranes (2LHPM) for the capture and release of white blood cells (WBCs)

A method modifying a vacuum-assisted UV micro-molding (VAUM) process is proposed for the fabrication of polymer two-level submicron high porosity membranes (2LHPM). The modified process allows for the fabrication of robust, large-area membranes over 5 × 5 cm2 with a hierarchical architecture made from a 200 nm-thick layer having submicron level pores (as small as 500 nm) supported by a 20 μm-thick layer forming a microporous structure with 10-15 μm diameter pores. The fabricated freestanding membranes are flexible and mechanically robust enough for post manipulation and filtration of cell samples. Very high white blood cell (WBC) capture efficiencies (≈97%) from healthy blood samples after red blood cell (RBC) lysis are demonstrated using a 3D-printed filter cartridge incorporated within these 2LHPM. A high release efficiency of ≈95% is also proved using the same setup. Finally, on-filter multistep immunostaining of captured cells is also shown.

Poly(butylene terephthalate) Fiber Assembly with Controllable Pore Size and Gradient Wettability: Potential in Simplifying Cell Culture Procedure

This study reports the scalable fabrication of a poly(butylene terephthalate) fiber assembly featured with controllable pore size and gradient wettability. Pore size is controlled via adjusting the throughput of melt blown process, while gradient wettability is achieved through single-sided plasma exposure and subsequent chitosan coating. When used in cell culture, the fiber assembly takes much less time in reaching a high cell collecting/releasing rate up to ≥99.5%, which is similar to that of the conventional centrifugal method. Other advantages of the fiber assembly, such as improved cell viability, reduced risk of contamination, and excellent reusability are also proved, leading us to believe its great potential in making the current cell culture procedure simpler and faster.

Fluorescence detection, enumeration and characterization of single circulating cells in vivo: technology, applications and future prospects

There are many diseases and biological processes that involve circulating cells in the bloodstream, such as cancer metastasis, immunology, reproductive medicine, and stem cell therapies. This has driven significant interest in new technologies for the study of circulating cells in small animal research models and clinically. Most currently used methods require drawing and enriching blood samples from the body, but these suffer from a number of limitations. In contrast, 'in vivo flow cytometry' (IVFC) refers to set of technologies that allow study of cells directly in the bloodstream of the organism in vivo. In recent years the IVFC field has grown significantly and new techniques have been developed, including fluorescence microscopy, multi-photon, photo-acoustic, and diffuse fluorescence IVFC. In this paper we review recent technical advances in IVFC, with emphasis on instrumentation, contrast mechanisms, and detection sensitivity. We also describe key applications in biomedical research, including cancer research and immunology. Last, we discuss future directions for IVFC, as well as prospects for broader adoption by the biomedical research community and translation to humans clinically.

Improving chondrocyte harvests with poly(2-hydroxyethyl methacrylate) coated materials in the preparation for cartilage tissue engineering

Remarkable advances have been made in cartilage regenerative medicine to cure congenital anomalies including microtia, tissue defects caused by craniofacial injuries, and geriatric diseases such as osteoarthritis. However, those procedures require a substantial quantity of chondrocytes for tissue engineering. Previous studies have required several passages to obtain sufficient cell numbers for three-dimensional and monolayer cultures. Thus, our objective was to improve the quantity of chondrocytes that can be obtained by examining an anti-fouling polyhydrophilic chemical called poly(2-hydroxyethyl methacrylate) (pHEMA). To determine the effectiveness of the chemical, pHEMA solution was applied via dip-coating to centrifuge tubes, serological pipettes, and pipette tips. The cell quantity obtained during standard cell culturing and passaging procedures was measured alongside non-coated materials as a control. A significant 2.2-fold increase of chondrocyte yield was observed after 2 passages when pHEMA was applied to the tubes compared to when non-coated tubes were utilized. The 3-dimensional chondrocyte pellets prepared from the respective cell populations and transplanted into nude mice were histologically and biochemically analyzed. No evidence of difference in matrix production for in vitro and in vivo cultures was found as well as similar proliferation rates and colony formation abilities. The use of pHEMA provides a powerful alternative method for expanding the quantity of chondrocytes harvested and handled during cell isolation and passaging to enhance cartilage tissue engineering.

Expansion of bone marrow-derived human mesenchymal stem/stromal cells (hMSCs) using a two-phase liquid/liquid system

BACKGROUND

Human mesenchymal stem/stromal cells (hMSCs) are at the forefront of regenerative medicine applications due to their relatively easy isolation and availability in adults, potential to differentiate and to secrete a range of trophic factors that could determine specialised tissue regeneration. To date, hMSCs have been successfully cultured in vitro on substrates such as polystyrene dishes (TCPS) or microcarriers. However, hMSC sub-cultivation and harvest typically employs proteolytic enzymes that act by cleaving important cell membrane proteins resulting in long-term cell damage. In a process where the cells themselves are the product, a non-enzymatic and non-damaging harvesting approach is desirable.

RESULTS

An alternative system for hMSC expansion and subsequent non-enzymatic harvest was investigated here. A liquid/liquid two-phase system was proposed, comprising a selected perfluorocarbon (FC40) and growth medium (DMEM). The cells exhibited similar cell morphologies compared with TCPS. Moreover, they retained their identity and differentiation potential post-expansion and post-harvest. Further, no significant difference was found when culturing hMSCs in the culture systems prepared with either fresh or recycled FC40 perfluorocarbon.

CONCLUSIONS

These findings make the FC40/DMEM system an attractive alternative for traditional cell culture substrates due to their ease of cell recovery and recyclability, the latter impacting on overall process costs. © 2017 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.