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One of the current difficulties limiting the use of adoptive cell therapy (ACT) for cancer treatment is the lack of methods for rapidly expanding T cells. As described in the present report, we developed a centrifugal bioreactor (CBR) that may resolve this manufacturing bottleneck. The CBR operates in perfusion by balancing centrifugal forces with a continuous feed of fresh medium, preventing cells from leaving the expansion culture chamber while maintaining nutrients for growth. A bovine CD8 cytotoxic T lymphocyte (CTL) cell line specific for an autologous target cell infected with a protozoan parasite,Theileria parva, was used to determine the efficacy of the CBR for ACT purposes. Batch culture experiments were conducted to predict how CTLs respond to environmental changes associated with consumption of nutrients and production of toxic metabolites, such as ammonium and lactate. Data from these studies were used to develop a kinetic growth model, allowing us to predict CTL growth in the CBR and determine the optimal operating parameters. The model predicts the maximum cell density the CBR can sustain is 5.5 × 10⁷ cells/mL in a single 11‐mL conical chamber with oxygen being the limiting factor. Experimental results expanding CTLs in the CBR are in 95% agreement with the kinetic model. The prototype CBR described in this report can be used to develop a CBR for use in cancer immunotherapy.

 

This work is focused on designing an easy‐to‐use novel perfusion system for articular cartilage (AC) tissue engineering and using it to elucidate the mechanism by which interstitial shear upregulates matrix synthesis by articular chondrocytes (AChs). Porous chitosan‐agarose (CHAG) scaffolds were synthesized and compared to bulk agarose (AG) scaffolds. Both scaffolds were seeded with osteoarthritic human AChs and cultured in a novel perfusion system with a medium flow velocity of 0.33 mm/s corresponding to 0.4 mPa surfice shear and 40 mPa CHAG interstitial shear. While there were no statistical differences in cell viability for perfusion versus static cultures for either scaffold type, CHAG scaffolds exhibited a 3.3‐fold higher (p < 0.005) cell viability compared to AG scaffold cultures. Effects of combined superficial and interstitial perfusion for CHAG showed 150‐ and 45‐fold (p < 0.0001) increases in total collagen (COL) and 13‐ and 2.2‐fold (p < 0.001) increases in glycosaminoglycans (GAGs) over AG non‐perfusion and perfusion cultures, respectively, and a 1.5‐fold and 3.6‐fold (p < 0.005) increase over non‐perfusion CHAG cultures. Contrasting CHAG perfusion and static cultures, chondrogenic gene comparisons showed a 3.5‐fold increase in collagen type II/type I (COL2A1/COL1A1) mRNA ratio (p < 0.05), and a 1.3‐fold increase in aggrecan mRNA. Observed effects are linked to NF‐κB signal transduction pathway inhibition as confirmed by a 3.2‐fold (p < 0.05) reduction of NF‐κB mRNA expression upon exposure to perfusion. Our results demonstrate that pores play a critical role in improving cell viability and that interstitial flow caused by medium perfusion through the porous scaffolds enhances the expression of chondrogenic genes and extracellular matrix through downregulating NF‐κB1.

 

A novel miniaturized, transparent reactor system for use as either a research or educational tool was developed for investigating biomass char gasification with oxygen to determine the kinetic parameters. Parametric temperature and pressure data taken can be used to distinguish the validity of assumptions inherent in the Avrami, the random pore (RPM), the unreacted core shrinking (UCSM), and a UCSM hybrid models (HM). The results demonstrate the UCSM for spherical and cylindrical geometries, and an HM variation with a best-fit exponent, that yields residual sums of squares 2 to 4 orders of magnitude lower than other models. An Arrhenius evaluation yielded an activation energy of 84.8 kJ/mol and pre-exponential factor of 1.34  103 s-1. An O2 reaction order of 0.85 indicates O2 adsorption on the char surface is the primary rate-controlling step. Data are consistent with a rapidly decreasing surface area as the reaction nears completion, suggesting available corresponding active sites for rapid chemisorption decrease as the reaction progresses. More importantly, the design of the system is safe to take into the classroom while simultaneously allowing students to view real-time reactions and produce repeatable data; this pushes the bounds on classroom interventions and learning.