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Cold Atmospheric plasma has been studied extensively over the last decade with applications ranging from bacterial decontamination to wound healing. Although numerous designs of plasma applicators have been developed for direct exposure, prolonged exposure required for decontamination of tissues and skin may be detrimental to mammalian cells. In this study, we evaluate the effect of plasma generated by surface dielectric barrier discharge (SDBD) on mammalian cells, including HUVEC, Neuroblastoma, and HepG2. SDBD actuator induces flow and can transport plasma‐generated species to the surface being treated. Cell morphology, viability, and functionality are evaluated by incubating cells after exposure to SDBD for 1, 4 and 8 min. All cell types demonstrate retention of viability without any necrotic response, although, with an increase in the number of injured cells, with increase in exposure time. Cell‐specific responses are observed with HUVEC demonstrating highest resilience as compared to neuroblastoma and HepG2 (lowest). Migration assay using HUVEC shows no effect on viability and functionality with 4 min exposure. The 8 min tests demonstrated no additional change in morphology, so we conclude that SDBD does not affect the cell morphology at longer exposure durations as compared to other plasma sources and can be applied safely in medical applications.

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An improved adenoviral-based gene delivery vector was developed by complexing adenovirus (Ad) with a biocompatible, grafted copolymer PEG-g-PEI composed of polyethylene glycol (PEG) and polyethylenimine (PEI). Although an Ad-based gene vector is considered relatively safe, its native tropism, tendency to elicit an immune response, and susceptibility to inactivating antibodies makes the virus less than ideal. The goal of the current study was to determine whether Ad could be complexed with a PEG-g-PEI copolymer that would enable the virus to transduce cells lacking the Ad receptor, while avoiding the issues commonly associated with PEI. A copolymer library was synthesized using 2 kDa PEG and either linear or branched PEI (25 kDa) with a PEG to PEI grafting ratio of 10, 20, or 30. The results of the study indicate that PEG-g-PEI/Ad complexes are indeed able to transduce CAR-negative NIH 3T3 cells. The results also demonstrate that the PEG-g-PEI/Ad complexes are less toxic, less hemolytic, and more appropriately sized than PEI/Ad complexes.

In this study, the distribution of oxygen and glucose was evaluated along with consumption by hepatocytes using three different approaches. The methods include (i) Computational Fluid Dynamics (CFD) simulation, (ii) residence time distribution (RTD) analysis using a step-input coupled with segregation model or dispersion model, and (iii) experimentally determined consumption by HepG2 cells in an open-loop. Chitosan-gelatin (CG) scaffolds prepared by freeze-drying and polycaprolactone (PCL) scaffolds prepared by salt leaching technique were utilized for RTD analyses. The scaffold characteristics were used in CFD simulations i.e. Brinkman's equation for flow through porous medium, structural mechanics for fluid induced scaffold deformation, and advection-diffusion equation coupled with Michaelis-Menten rate equations for nutrient consumption. With the assumption that each hepatocyte behaves like a micro-batch reactor within the scaffold, segregation model was combined with RTD to determine exit concentration. A flow rate of 1 mL/min was used in the bioreactor seeded with 0.6 × 10(6) HepG2 cells/cm(3) on CG scaffolds and oxygen consumption was measured using two flow-through electrodes located at the inlet and outlet. Glucose in the spent growth medium was also analyzed. RTD results showed distribution of nutrients to depend on the surface characteristics of scaffolds. Comparisons of outlet oxygen concentrations between the simulation results, and experimental results showed good agreement with the dispersion model. Outlet oxygen concentrations from segregation model predictions were lower. Doubling the cell density showed a need for increasing the flow rate in CFD simulations. This integrated approach provide a useful strategy in designing bioreactors and monitoring tissue regeneration.

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