Atmospheric-pressure plasmas (APPs) have attracted great interest and have been widely applied in biomedical applications, as due to their non-thermal and reactive properties, they interact with living tissues, cells and bacteria. Various types of plasma sources generated at atmospheric pressure have been developed to achieve better performance in specific applications. This article presents an overview of the general characteristics of APPs and a brief summary of their biomedical applications, and reviews a wide range of these sources developed for biomedical applications. The plasma sources are classified according to their power sources and cover a wide frequency spectrum from dc to microwaves. The configurations and characteristics of plasma sources are outlined and their biomedical applications are presented.

Autophagy plays a critical role in maintaining cell homeostasis in response to various stressors through protein conjugation and activation of lysosome-dependent degradation. MAP1LC3B/LC3B (microtubuleassociated protein 1 light chain 3 b) is conjugated with phosphatidylethanolamine (PE) in the membranes and regulates initiation of autophagy through interaction with many autophagy-related proteins possessing an LC3-interacting region (LIR) motif, which is composed of 2 hydrophobic amino acids (tryptophan and leucine) separated by 2 non-conserved amino acids (WXXL). In this study, we identified a new putative LIR motif in PEBP1/RKIP (phosphatidylethanolamine binding protein 1) that was originally isolated as a PE-binding protein and also a cellular inhibitor of MAPK/ERK signaling. PEBP1 was specifically bound to PE-unconjugated LC3 in cells, and mutation (WXXL mutated to AXXA) of this LIR motif disrupted its interaction with LC3 proteins. Interestingly, overexpression of PEBP1 significantly inhibited starvationinduced autophagy by activating the AKT and MTORC1 (mechanistic target of rapamycin [serine/ threonine kinase] complex 1) signaling pathway and consequently suppressing the ULK1 (unc-51 like autophagy activating kinase 1) activity. In contrast, ablation of PEBP1 expression dramatically promoted the autophagic process under starvation conditions. Furthermore, PEBP1 lacking the LIR motif highly stimulated starvation-induced autophagy through the AKT-MTORC1-dependent pathway. PEBP1 phosphorylation at Ser153 caused dissociation of LC3 from the PEBP1-LC3 complex for autophagy induction. PEBP1-dependent suppression of autophagy was not associated with the MAPK pathway. These findings suggest that PEBP1 can act as a negative mediator in autophagy through stimulation of the AKT-MTORC1 pathway and direct interaction with LC3.

biodegradable polymer scaffolds were widely studied for bone regeneration because the metal implants have the limitations of non-degradability and high rigidity. [2,3] Common methods for fabricating such a scaffold include particulate leaching, electrospinning, and freeze-drying. However, these methods have limited reproducibility and versatility in their manufacturing processes. [4] To solve these problems, the 3D bioprinting technology for making scaffolds by stacking printing materials has been applied. [5] This 3D bioprinting technology can control the architecture of fabricated structures, so that it only comprises interconnected networks, and also controls the shape of the scaffold. Interconnected pores are an important component of tissue engineering scaffolds because they play roles in cell viability, migration, proliferation, and differentiation. [6] In addition, reproducibility can be guaranteed by bioprinting. β-tri-calcium phosphate (β-TCP) is known to form new bone with osteoconductive properties and are widely applied for bone regeneration. The solubility of β-TCP is higher than that of hydroxyapatite, so it forms higher-density aggregates to bone defects, thereby promoting bone formation. [7,8] Gelatin, a natural polymer derived from partially hydrolyzed collagen, has biological properties such as biocompatibility and 3D printed scaffolds composed of gelatin and β-tri-calcium phosphate (β-TCP) as a biomimetic bone material are fabricated, thereby providing an environment appropriate for bone regeneration. The Ca 2+ in β-TCP and COO − in gelatin form a stable electrostatic interaction, and the composite scaffold shows suitable rheological properties for bioprinting. The gelatin/β-TCP scaffold is crosslinked with glutaraldehyde vapor and unreacted aldehyde groups which can cause toxicity to cells is removed by a glycine washing. The stable binding of the hydrogel is revealed as a result of FTIR and degradation rate. It is confirmed that the composite scaffold has compressive strength similar to that of cancellous bone and 60 wt% β-TCP groups containing 40 wt% gelatin have good cellular activity with preosteoblasts. Also, in the animal experiments, the gelatin/β-TCP scaffold confirms to induce bone formation without any inflammatory responses. This study suggests that these fabricated scaffolds can serve as a potential bone substitute for bone regeneration.

Raf kinase inhibitory protein (RKIP), an endogenous inhibitor of the extracellular signal-regulated kinase (ERK) pathway, has been implicated as a suppressor of metastasis and a prognostic marker in cancers. However, how RKIP acts as a suppressor during metastasis is not fully understood. Here, we show that RKIP activity in cervical and stomach cancer is inversely correlated with endogenous levels of the Notch1 intracellular domain (NICD), which stimulates the epithelial to mesenchymal transition (EMT) and metastasis. The levels of RKIP were significantly decreased in tumor tissues compared to normal tissues, whereas NICD levels were increased. Overexpression of RKIP in several cell lines resulted in a dramatic decrease of NICD and subsequent inhibition of several mesenchymal markers, such as vimentin, N-cadherin, and Snail. In contrast, knockdown of RKIP exhibited opposite results both in vitro and in vivo using mouse models. Nevertheless, knockdown of Notch1 in cancer cells had no effect on the expression of RKIP, suggesting that RKIP is likely an upstream regulator of the Notch1 pathway. We also found that RKIP directly interacts with Notch1 but has no influence on the intracellular level of the γ-secretase complex that is necessary for Notch1 activation. These data suggest that RKIP plays a distinct role in activation of Notch1 during EMT and metastasis, providing a new target for cancer treatment.

Oral cavity and teeth are important organs of human body. The attention and cost for dental treatments increase every year. In dental clinics, the most common diseases are dental caries, periodontal disease, and stomatitis. Dental aesthetics such as tooth whitening is one of important part of dental clinics. However, conventional treatment methods in dental clinics have limitations by pain and long‐time treatment. Nonthermal plasmas have shown great potential as noble techniques to dental applications due to safety and multi‐functional effects achieved by the abundant plasma components including charged particles, radiation, and reactive species. Reactive oxygen species generated from plasmas can effectively inhibit pathogen activity. The use of nonthermal plasmas is efficient in treating oral diseases because the construction of the plasma devices allows easy access to the oral cavity. However, few studies have been conducted on the use of plasmas in oral disease. Tooth aesthetics, as well as treatment of oral diseases, are important in determining the quality of human life. Recent studies have shown nonthermal plasmas to have strong tooth‐bleaching effects. Studies on oral care using nonthermal plasmas will significantly contribute to oral health in the future. magnified image