Effects of minimal exposures to atmospheric pressure plasma on the activity of Salmonella Typhimurium: Deactivation of bacterial motility and suppression of host-cell invasion.

Atmospheric pressure plasma (APP) has been shown effective in sterilization by reducing the number of viable microbes during surface cleaning, food processing, or human tissue treatment. For safe conduct, the majority of previous research focused on complete abolition of microbes, which may require severe treatments. Our aim is to investigate the minimal treatment conditions necessary for effective inactivation of bacteria in such a manner that the APP treated bacteria would not be able to harm the host cells. For this, we ought to identify the objective criteria to make the bacteria dysfunctional. We choose the motile properties and the host-cell invasion capability as two measures to quantify the pathogenic state of bacteria. In this paper, we investigated how the APP treatment in a minimal dosage affects the activity of Salmonella Typhimurium. At 100 W and 15 kHz for 20 s, the APP treatment effectively suppressed active "run and tumble" type motility and induced formation of abnormally long structures. With 20 s exposure, the bacterial cells failed to cause pyroptosis in the host cells with >90% survival after 12 h of co-incubation. Our results suggest novel measures to evaluate the functional pathogenic state for identifying safe APP treatment conditions.

Electrospun Microvasculature for Rapid Vascular Network Restoration.

BACKGROUND: Sufficient blood supply through neo-vasculature is a major challenge in cell therapy and tissue engineering in order to support the growth, function, and viability of implanted cells. However, depending on the implant size and cell types, the natural process of angiogenesis may not provide enough blood supply for long term survival of the implants, requiring supplementary strategy to prevent local ischemia. Many researchers have reported the methodologies to form pre-vasculatures that mimic in vivo microvessels for implantation to promote angiogenesis. These approaches successfully showed significant enhancement in long-term survival and regenerative functions of implanted cells, yet there remains room for improvement. METHODS: This paper suggests a proof-of-concept strategy to utilize novel scaffolds of dimpled/hollow electrospun fibers that enable the formation of highly mature pre-vasculatures with adequate dimensions and fast degrading in the tissue. RESULT: Higher surface roughness improved the maturity of endothelial cells mediated by increased cell-scaffold affinity. The degradation of scaffold material for functional restoration of the neo-vasculatures was also expedited by employing the hollow scaffold design based on co-axial electrospinning techniques. CONCLUSION: This unique scaffold-based pre-vasculature can hold implanted cells and tissue constructs for a prolonged time while minimizing the cellular loss, manifesting as a gold standard design for transplantable scaffolds.