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Spinning of Dialysis Grade Membranes
Published in Sirshendu De, Anirban Roy, Hemodialysis Membranes, 2017
The following polymer blend solutions (in DMF [dimethyl formamide] solvent) were synthesized using the technique mentioned in Chapter 4. These solutions were used for both FTIR and rheological analyses: PSf (18 wt%) and PEG (3 wt%)—referred to as PVP 0PSf (18 wt%), PEG (3 wt%), and PVP (3 wt%)—referred to as PVP 3PSf (18 wt%) and PVP (2 wt%)—referred to as PEG 0PSf (18 wt%), PVP (2 wt%), and PEG (3 wt%)—referred to as PEG 3 For hollow-fiber membrane spinning, the following compositions were used: PSf (18 wt%), PEG (3 wt%), and PVP (0 wt%)—referred to as 6 kDaPSf (18 wt%), PEG (3 wt%), and PVP (2 wt%)—referred to as 12 kDaPSf (18 wt%), PEG (3 wt%), and PVP (3 wt%)—referred to as 16 kDa Flat-sheet membranes with the same composition as hollow fibers for contact angle analysis were prepared. The process is the same as discussed in Chapter 4.
Cell-Based Delivery Systems: Development of Encapsulated Cell Technology for Ophthalmic Applications
Published in Glenn J. Jaffe, Paul Ashton, P. Andrew Pearson, Intraocular Drug Delivery, 2006
Weng Tao, Rong Wen, Alan Laties, Gustavo D. Aguirre
An intraocular implantable encapsulated cell unit prototype for chronic delivery of therapeutic agents has been developed to treat ophthalmic disorders (Fig. 2) (11). The implant consists of genetically modified cells packaged in a hollow, semipermeable membrane. The hollow fiber membrane (HFM) prevents immune molecules, e.g., antibodies and host immune cells, from entering the implant, while allowing nutrients and therapeutic molecules to diffuse freely across the membrane. The encapsulated cells continuously secrete therapeutic agents (Fig. 2A), and derive nourishment from the host milieu. The ECT capsule is implanted through a small pars plana incision and anchored to the sclera by a small titanium wire loop (Fig. 2B). The active intravitreal portion of the implant measures ~ 1 mm in diameter and 10 mm in length. It is fixed outside the visual axis.
Modeling of mass transfer in vacuum membrane distillation process for radioactive wastewater treatment using artificial neural networks
Published in Toxin Reviews, 2021
Elena-Niculina Dragoi, Yasser Vasseghian
The common MD types are: direct contact membrane distillation (DCMD), air gap membrane distillation (AGMD), sweeping gas membrane distillation (SGMD), and vacuum membrane distillation (VMD; El-Bourawi et al.2007). DCMD is the simplest type of MD, but the major problem with this method is that when the permeate solution is in direct contact with the membrane, if the membrane is damaged, it causes contamination of the permeate solution (Ashoor et al.2016). In the other three MD methods, the risk of permeate pollution is lower because there is a separation between membrane and permeate. Among the three most recent methods, VMD is preferred because it uses a vacuum atmosphere on the shell side in the membrane column; this results in a faster penetrability of the steam, which leads to an increase of the driving force of mass transfer (El-Bourawi et al.2006). In the VMD method, three types of membrane columns are usually used: flat sheet, spiral wound, or hollow fiber membrane. Due to its surface density area, the hollow fiber membrane is most used in VMD (El-Bourawi et al.2006).
Manufacturing T cells in hollow fiber membrane bioreactors changes their programming and enhances their potency
Published in OncoImmunology, 2021
Seung Mi Yoo, Vivan W.C. Lau, Craig Aarts, Bojana Bojovic, Gregory Steinberg, Joanne A. Hammill, Anna Dvorkin-Gheva, Raja Ghosh, Jonathan L. Bramson
The principal component of the membrane bioreactor system is a hollow fiber membrane module. (Repligen; C02-E300-05-N). The hollow fiber membrane module used in this study contained six hollow fiber membranes, the total membrane surface area being 20 cm2. The PBMCs were grown outside the fibers (i.e. in the shell side or in the extracapillary space, EC). The lumen of the fibers (i.e. the intracapillary space, IC) were used to transfer nutrients, metabolites and oxygen as explained in Figures 1B and 1C. The hydraulic permeability and sieving coefficient of the hollow fiber membrane allows nutrients, metabolites, and gases easily across the fiber from IC side to EC side, while the T cells and the α-CD3/CD28 activating beads are retained on the EC side of the bioreactor. The culture manipulations such as aeration and media exchange are managed using two ISMATEC peristaltic pumps (model # C.P. 78023–20, 78016–30; Cole-Parmer Instrument Co. Vernon Hills, USA), and a set of valves and fittings (Nordson Medical and Cole-Parmer), which direct the flow of the different fluids through the disposal tubing set (Cole-Parmer Instrument Co. Vernon Hills, USA) shown in Supplemental Figure 4. The bioreactor was set up as a single-use, closed system where disposable tubing was used for aeration, media perfusion, virus addition, and effluent (waste) collection. During the manufacturing process, the culture media was delivered from a media bag, stored in a Styrofoam box, cooled with a gel ice packs to maintain the integrity of the medium. The membrane module was placed in a conventional cell culture incubator (5% CO2, 37°C and over 95% humidity). Gas exchange in the bioreactor was mediated by flushing the hollow fiber membranes with the gas mixture from the interior of the cell culture incubator.