First demonstration of Sn diffusion into gallium oxide from poly-tetraallyl tin deposited by initiated chemical vapor deposition by thermal treatment.

Gallium oxide (Ga2O3) is attracting attention as a next-generation semiconductor material for power device because it has a wide energy band gap and high breakdown electric field. We deposited a Sn polymer, poly-tetraallyl tin (pTASn), on Ga2O3 samples using a disclosed chemical vapor deposition (iCVD) process. The Sn dopant of the Sn polymer layer is injected into the Ga2O3 through a heat treatment process. Diffusion model of Sn into the Ga2O3 is proposed through secondary ion mass spectroscopy (SIMS) analysis and bond dissociation energy. The fabricated device exhibited typical n-type FET behavior. Ga2O3 Sn-doping technology using iCVD will be applied to 3D structures and trench structures in the future, opening up many possibilities in the Ga2O3-based power semiconductor device manufacturing process.

Conditioned media derived from human fetal progenitor cells improves skin regeneration in burn wound healing.

Stem cells are known to have excellent regenerative ability, which is primarily facilitated by indirect paracrine factors, rather than via direct cell replacement. The regenerative process is mediated by the release of extracellular matrix molecules, cytokines, and growth factors, which are also present in the media during cultivation. Herein, we aimed to demonstrate the functionality of key factors and mechanisms in skin regeneration through the analysis of conditioned media derived from fetal stem cells. A series of processes, including 3D pellet cultures, filtration and lyophilization is developed to fabricate human fetal cartilage-derived progenitor cells-conditioned media (hFCPCs-CM) and its useful properties are compared with those of human bone marrow-derived MSCs-conditioned media (hBMSCs-CM) in terms of biochemical characterization, and in vitro studies of fibroblast behavior, macrophage polarization, and burn wound healing. The hFCPCs-CM show to be devoid of cellular components but to contain large amounts of total protein, collagen, glycosaminoglycans, and growth factors, including IGFBP-2, IGFBP-6, HGF, VEGF, TGF ß3, and M-CSF, and contain a specific protein, collagen alpha-1(XIV) compare with hBMSCs-CM. The therapeutic potential of hFCPCs-CM observes to be better than that of hBMSCs-CM in the viability, proliferation, and migration of fibroblasts, and M2 macrophage polarization in vitro, and efficient acceleration of wound healing and minimization of scar formation in third-degree burn wounds in a rat model. The current study shows the potential therapeutic effect of hFCPCs and provides a rationale for using the secretome released from fetal progenitor cells to promote the regeneration of skin tissues, both quantitatively and qualitatively. The ready-to-use product of human fetal cartilage-derived progenitor cells-conditioned media (hFCPCs-CM) are fabricated via a series of techniques, including a 3D culture of hFCPCs, filtration using a 3.5 kDa cutoff dialysis membrane, and lyophilization of the CM. hFCPCs-CM contains many ECM molecules and biomolecules that improves wound healing through efficient acceleration of M2 macrophage polarization and reduction of scar formation.

Synergistic effect of three-dimensional coculture and photobiomodulation therapy on vascularized liver spheroid formation by stem cells.

Despite studies reporting functional differentiation of liver cells, a three-dimensional, vascularized liver organ has yet to be developed from mesenchymal stem cells. We investigated whether treatment with photobiomodulation (PBM) before three-dimensional liver spheroid transplantation improved the recovery of liver function via stimulation of angiogenesis and hepatocyte differentiation. Liver spheroids composed of hepatic, endothelial, and mesenchymal cells were subjected to PBM therapy. To evaluate the in vivo therapeutic effect of the liver spheroids treated with PBM, phosphate-buffered saline, liver spheroid, and PBM-treated liver spheroid were transplanted into a damaged host liver using conventional chimeric mouse models. To further characterize the maturation of transplanted PBM-liver spheroid compared with the newly generated non-PBM-liver spheroid or human liver tissues, the expression profiles of mature liver signature genes were analyzed. Liver spheroids expressed hepatocyte growth factors, including vascular endothelial growth factor and angiogenic factors. The cells in liver spheroid compensated for the low viability and improved the function of hepatocytes. Here, we demonstrate the formation of vascularized and functional human liver spheroid from human adipose-derived stem cells by transplantation of liver tissue created in vitro. Albumin secretion by PBM-treated liver spheroid was higher on Day 28 compared with liver spheroid-seeded transplant group. PBM-liver spheroids serve as individual vascularization units, promoting the simultaneous development of new microvascular networks at different locations inside the implanted tissue constructs. The vasculature in the liver spheroid transplants became functional by connecting to the host vessels within 48 h. These PBM-liver spheroids may be useful in designing artificial three-dimensional hepatic tissue constructs and in cell therapy with limited numbers of human hepatocytes.

The Supernatant of Tonsil-Derived Mesenchymal Stem Cell Has Antiallergic Effects in Allergic Rhinitis Mouse Model.

METHODS: We isolated T-MSCs from human palatine tonsil and evaluated the ingredients of T-MSCs-CM. The effect of T-MSCs-CM was evaluated in the AR mouse model that was randomly divided into five groups (negative control, positive control, and T-MSCs-CM treated (0.1 mg, 1 mg, and 10 mg)). To investigate the therapeutic effect, we analyzed rhinitis symptoms, serum immunoglobulin (Ig), inflammatory cells, and cytokine expression. We also assessed T cell receptor signal, including MAP kinase (ERK/JNK), p65, and NFAT1. RESULTS: We identified the increment of TGF-ß1, PGE2, and HGF in the T-MSCs-CM. In an animal study, the T-MSCs-CM-treated group showed significantly reduced allergic symptoms and infiltration of eosinophils and neutrophils in the nasal mucosa, whereas there was no significant difference in total IgE and the OVA-specific IgE level. Additionally, we found that the 10 mg T-MSCs-CM-treated group showed a significantly decreased IL-4 mRNA expression, compared to the (+) Con group. In the analysis of T cell receptor signal, the phosphorylation of MAP kinases, translocation of p65, and activation of NFAT1 were inhibited after T-MSCs-CM. CONCLUSIONS: Our findings suggest that T-MSCs-CM showed a partial immunomodulatory effect on the AR mouse model by the inhibition of T cell activation via MAP kinase, p65, and NFAT1.

Sizable Scaffold-Free Tissue-Engineered Articular Cartilage Construct for Cartilage Defect Repair.

This study introduces an implantable scaffold-free cartilage tissue construct (SF) that is composed of chondrocytes and their self-produced extracellular matrix (ECM). Chondrocytes were grown in vitro for up to 5 weeks and subjected to various assays at different time points (1, 7, 21, and 35 days). For in vivo implantation, full-thickness defects (n = 5) were manually created on the trochlear groove of the both knees of rabbits (16-week old) and 3 week-cultured SF construct was implanted as an allograft for a month. The left knee defects were implanted with 1, 7, and 21 days in vitro cultured scaffold-free engineered cartilages. (group 2, 3, and 4, respectively). The maturity of the engineered cartilages was evaluated by histological, chemical and mechanical assays. The repair of damaged cartilages was also evaluated by gross images and histological observations at 4, 8, and 12 weeks postsurgery. Although defect of groups 1, 2, and 3 were repaired with fibrocartilage tissues, group 4 (21 days) showed hyaline cartilage in the histological observation. In particular, mature matrix and columnar organization of chondrocytes and highly expressed type II collagen were observed only in 21 days in vitro cultured SF cartilage (group 4) at 12 weeks. As a conclusion, cartilage repair with maturation was recapitulated when implanted the 21 day in vitro cultured scaffold-free engineered cartilage. When implanting tissue-engineered cartilage, the maturity of the cartilage tissue along with the cultivation period can affect the cartilage repair.

Preparation of Fe-Carbon Nanocomposite by Pyrolyzing Fe Adsorbed 1,8-Diamminonaphthalene for the Adsorption of Cr (VI).

In the present work, a facile method for the preparation of nanocomposite adsorbents composed of carbon and iron compounds was demonstrated. The adsorbents were produced by pyrolyzing an iron-coordinated 1,8-diaminonaphthalene at various temperatures under an N2 stream (FeDN X, where X represents the pyrolysis temperatures 600, 700, and 800 °C). Prepared FeDNs were employed as adsorbents for the removal of Cr (VI). The Cr (VI)-adsorption behavior of FeDNs were well-fitted to a Langmuir isotherm model. Among the samples prepared, FeDN 700 showed the best performance for the removal of Cr (VI). In particular, the maximum adsorption capacity of FeDN 700 was evaluated to be 34.81 mg/g. A variety of characterizations were carried out to elucidate the relationship between physical properties of adsorbents and their adsorption behaviors.

Non-Linear Cellular Dielectrophoretic Behavior Characterization Using Dielectrophoretic Tweezers-Based Force Spectroscopy inside a Microfluidic Device.

Characterization of cellular dielectrophoretic (DEP) behaviors, when cells are exposed to an alternating current (AC) electric field of varying frequency, is fundamentally important to many applications using dielectrophoresis. However, to date, that characterization has been performed with monotonically increasing or decreasing frequency, not with successive increases and decreases, even though cells might behave differently with those frequency modulations due to the nonlinear cellular electrodynamic responses reported in previous works. In this report, we present a method to trace the behaviors of numerous cells simultaneously at the single-cell level in a simple, robust manner using dielectrophoretic tweezers-based force spectroscopy. Using this method, the behaviors of more than 150 cells were traced in a single environment at the same time, while a modulated DEP force acted upon them, resulting in characterization of nonlinear DEP cellular behaviors and generation of different cross-over frequencies in living cells by modulating the DEP force. This study demonstrated that living cells can have non-linear di-polarized responses depending on the modulation direction of the applied frequency as well as providing a simple and reliable platform from which to measure a cellular cross-over frequency and characterize its nonlinear property.

Preparation of highly stable zeolite-alginate foam composite for strontium(90Sr) removal from seawater and evaluation of Sr adsorption performance.

Alginate bead is a promising strontium (Sr) adsorbent in seawater, but highly concentrated Na ions caused over-swelling and damaged the hydrogel bead. To improve the mechanical stability of alginate bead, flexible foam-type zeolite-alginate composite was synthesized and Sr adsorption performance was evaluated in seawater; 1-10% zeolite immobilized alginate foams were prepared by freeze-dry technique. Immobilization of zeolite into alginate foam converted macro-pores to meso-pores which lead to more compact structure. It resulted in less swollen composite in seawater medium and exhibited highly improved mechanical stability compared with alginate bead. Besides, Sr adsorption efficiency and selectivity were enhanced by immobilization of zeolite in alginate foam due to the increase of Sr binding sites (zeolite). In particular, Sr selectivity against Na was highly improved. The 10% zeolite-alginate foam exhibited a higher log Kd of 3.3, while the pure alginate foam exhibited 2.7 in the presence of 0.1 M Na. Finally, in the real seawater, the 10% zeolite-alginate foam exhibited 1.5 times higher Sr adsorption efficiency than the pure alginate foam. This result reveals that zeolite-alginate foam composite is appropriate material for Sr removal in seawater due to its swelling resistance as well as improved Sr adsorption performance in complex media.

Adipose-derived stem cell spheroid treated with low-level light irradiation accelerates spontaneous angiogenesis in mouse model of hindlimb ischemia.

BACKGROUND AIMS: We investigated whether low-level light irradiation (LLLI) before adipose-derived stromal cells (ASCs) spheroid transplantation improved hind-limb functional recovery by stimulation of angiogenesis. METHODS: The spheroid, composed of ASCs, was irradiated with low-level light and expressed angiogenic factors, including vascular endothelial growth factor and basic fibroblast growth factor. From immunochemical staining analysis, the spheroid of ASCs included CD31+, KDR+ and CD34+, whereas monolayer-cultured ASCs were negative for these markers. To evaluate the therapeutic effect of the ASC spheroid treated with LLLI in vivo, phosphate-buffered saline, monolayer ASCs, LLLI-monolayer ASCs, spheroid ASCs and LLLI-spheroid ASCs were transplanted into a hind-limb ischemia model. RESULTS: The LLLI-spheroid ASCs transplanted into the hind-limb ischemia differentiated into endothelial cells and remained differentiated. Transplantation of LLLI-spheroid ASCs into the hind-limb ischemia significantly elevated the density of vascular formations through angiogenic factors released by the ASCs and enhanced tissue regeneration at the lesion site. Consistent with these results, the transplantation of LLLI-spheroid ASCs significantly improved functional recovery compared with ASC or spheroid ASC transplantation and PBS treatment. CONCLUSIONS: These findings suggest that transplantation of ASC spheroid treated with LLLI may be an effective stem cell therapy for the treatment of hind-limb ischemia and peripheral vascular disease.

Human adipose-derived stem cell spheroid treated with photobiomodulation irradiation accelerates tissue regeneration in mouse model of skin flap ischemia.

Skin flap grafting is a form of transplantation widely used in plastic surgery. However, ischemia/reperfusion injury is the main factor which reduces the survival rate of flaps following grafting. We investigated whether photobiomodulation (PBM) precondition prior to human adipose-derived stromal cell (hASC) spheroid (PBM-spheroid) transplantation improved skin tissue functional recovery by the stimulation of angiogenesis and tissue regeneration in skin flap of mice. The LED had an emission wavelength peaked at 660 ± 20 nm (6 J/cm2, 10 mW/cm2). The expression of angiogenic growth factors in PBM-spheroid hASCs was much greater than that of not-PBM-treated spheroid or monolayer-cultured hASCs. From immunochemical staining analysis, the hASCs of PBM-spheroid were CD31+, KDR+, and CD34+, whereas monolayer-cultured hASCs were negative for these markers. To evaluate the therapeutic effect of hASC PBM-spheroid in vivo, PBS, monolayer-cultured hASCs, and not-PBM-spheroid were transplanted into a skin flap model. The animals were observed for 14 days. The PBM-spheroid hASCs transplanted into the skin flap ischemia differentiated into endothelial cells and remained differentiated. Transplantation of PBM-spheroid hASCs into the skin flap ischemia significantly elevated the density of vascular formations through angiogenic factors released by the skin flap ischemia and enhanced tissue regeneration at the lesion site. Consistent with these results, the transplantation of PBM-spheroid hASCs significantly improved functional recovery compared with PBS, monolayer-cultured hASCs, and not-PBM-spheroid treatment. These findings suggest that transplantation of PBM-spheroid hASCs may be an effective stem cell therapy for the treatment of skin flap ischemia.

Angiogenic Synergistic Effect of Adipose-Derived Stromal Cell Spheroids with Low-Level Light Therapy in a Model of Acute Skin Flap Ischemia.

Human adipose-derived mesenchymal stem cells (hASCs) are an attractive cell source for tissue engineering. However, one obstacle to this approach is that the transplanted hASC population can decline rapidly in the recipient tissue. The aim of this study was to investigate the effects of low-level light therapy (LLLT) on transplanted spheroid hASCs in skin flaps of mice. hASCs were cultured in monolayers or spheroids. LLLT, hASCs, spheroids and spheroids transplanted with LLLT were applied to the skin flaps. Healing of the skin flaps was assessed by gross evaluation and by hematoxylin and eosin staining and elastin van Gieson staining. Compared with the spheroid group, skin flap healing was enhanced in the spheroid + LLLT group, including the neovascularization and regeneration of skin appendages. The survival of hASCs was enhanced by decreased apoptosis of hASCs in the skin flaps of the spheroid + LLLT group. The secretion of growth factors was stimulated in the spheroid + LLLT group compared with the ASC and spheroid groups. These data suggest that LLLT was an effective biostimulator of spheroid hASCs in the skin flaps, enhancing the survival of hASCs and stimulating the secretion of growth factors.

Investigation of the strontium (Sr(II)) adsorption of an alginate microsphere as a low-cost adsorbent for removal and recovery from seawater.

In this paper, we investigated alginate microspheres as a low-cost adsorbent for strontium (Sr(II)) removal and recovery from seawater. Alginate microspheres have demonstrated a superior adsorption capacity for Sr(II) ions (≈110 mg/g). A Freundlich isotherm model fits well with the Sr(II) adsorption of an alginate microsphere. The mechanism of Sr(II) adsorption is inferred as an ion exchange reaction with Ca(II) ions. The effects of the solution pH and co-existing ions in seawater are also investigated. Except for a pH of 1-2, Sr(II) adsorption capacity is not affected by pH. However, increasing the seawater concentration of metal cations seriously decreases Sr(II) uptake. In particular, highly concentrated (15,000 mg/L) Na(I) ions significantly interfere with Sr(II) adsorption. Sr(II) desorption was performed using 0.1 M HCl and CaCl2. Both regenerants show an excellent desorption efficiency, but the FTIR spectrum reveals that the chemical structure of the microsphere is destroyed after repeated use of HCl. Conversely, CaCl2 successfully desorbed Sr(II) without damage, and the Sr(II) adsorption capacity does not decrease after three repeated uses. The alginate microsphere was also applied to the adsorption of Sr(II) in a real seawater medium. Because of inhibition by co-existing ions, the Sr(II) adsorption capacity was decreased and the adsorption rate was retarded compared with D.I. water. Although the Sr(II) adsorption capacity was decreased, the alginate microsphere still exhibited 17.8 mg/g of Sr(II) uptake in the seawater medium. Considering its excellent Sr(II) uptake in seawater and its reusability, an alginate microsphere is an appropriate cost-effective adsorbent for the removal and recovery of Sr(II) from seawater.

Adipose-derived stromal cell cluster with light therapy enhance angiogenesis and skin wound healing in mice.

Human adipose-derived mesenchymal stem cells (hASCs) are attractive cell source for skin tissue engineering. The aim of this study was to investigate the effects of low-level light therapy (LLLT) on transplanted cluster hASC in a skin wound animal model. The hASCs were cultured in monolayer or clusters. The LLLT, hASCs, hASC clusters, and hASC clusters transplantation with LLLT (cluster + LLLT) were applied to the wound bed in athymic mice. Wound healing was assessed by gross evaluation and by hematoxylin and eosin staining, and elastin van gieson histochemistry. The survival, differentiation, and secretion of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (FGF), and hepatocyte growth factor (HGF) of the cluster ASC were evaluated by immunohistochemistry and Western blotting. The cluster + LLLT group enhanced the wound healing, including neovascularization and regeneration of skin appendages, compared with the cluster group. The secretion of growth factors was stimulated in the cluster + LLLT group compared with the ASCs and cluster group. These data suggest that LLLT is an effective biostimulator of cluster hASCs in wound healing that enhances the survival of hASCs and stimulates the secretion of growth factors in the wound bed.

Prevention of skin flap necrosis by use of adipose-derived stromal cells with light-emitting diode phototherapy.

BACKGROUND AIMS: The aim of this study was to investigate the effects of low-level light therapy (LLLT) on transplanted human adipose-derived mesenchymal stromal cells (ASCs) in the skin flap of mice. METHODS: LLLT, ASC transplantation and ASC transplantation with LLLT (ASC + LLLT) were applied to the skin flap. Immunostaining and Western blot analysis were performed to evaluate cell survival and differentiation and secretion of vascular endothelial growth factor and basic fibroblast growth factor by the ASCs. Vascular regeneration was assessed by means of immunostaining in addition to hematoxylin and eosin staining. In the ASC + LLLT group, the survival of ASCs was increased as the result of the decreased apoptosis of ASCs. RESULTS: The secretion of growth factors was higher in this group as compared with ASCs alone. ASCs contributed to tissue regeneration through vascular cell differentiation and secretion of angiogenic growth factors. The ASC + LLLT group displayed improved treatment efficacy including neovascularization and tissue regeneration compared with ASCs alone. Transplanting ASCs to ischemic skin flaps improved therapeutic efficacy for ischemia treatment as the result of enhanced cell survival and paracrine effects. CONCLUSIONS: These data suggest that LLLT is an effective biostimulator of ASCs in vascular regeneration, which enhances the survival of ASCs and stimulates the secretion of growth factors in skin flaps.

Vascular regeneration effect of adipose-derived stem cells with light-emitting diode phototherapy in ischemic tissue.

The objective of this study was to investigate the effects on the vascular regeneration of adipose-derived stem cells (ASCs) by using red light-emitting diode (LED) irradiation in ischemic hind limbs. Low-level light therapy (LLLT) has been shown to enhance proliferation and cytokine secretion of a number of cells. ASCs are an attractive cell source for vascular tissue engineering. This approach is hindered because transplanted ASCs decline rapidly in the recipient tissue. Ischemic hind limbs were treated with LLLT from an LED array (660 nm) at an irradiance of 50 mW/cm(2) and a radiant exposure of 30 J/cm(2). LLLT, ASC transplantation, and ASC transplantation with LLLT (ASC + LLLT) were applied to ischemic limbs, and cell survival and differentiation, and secretion of vascular endothelial growth factor and basic fibroblast growth factor of the ASCs were evaluated by immunostaining and Western blot analyses. Vascular regeneration was assessed by immunostaining and hematoxylin and eosin staining. In the ASC + LLLT group, the survival of ASCs was increased due to the decreased apoptosis of ASCs. The secretion of growth factors was stimulated in this group compared with ASCs alone. The ASC + LLLT group displayed improved treatment efficacy including neovascularization and tissue regeneration compared with ASCs alone. In particular, quantitative analysis of laser Doppler blood perfusion image ratio showed that blood perfusion was enhanced significantly (p < 0.05) by ASC + LLLT treatment. These data suggest that LLLT is an effective biostimulator of ASCs in vascular regeneration, which enhances the survival of ASCs and stimulates the secretion of growth factors in ischemic limbs.

A novel three-dimensional adipose-derived stem cell cluster for vascular regeneration in ischemic tissue.

BACKGROUND AIMS: Stem cells are one of the most powerful tools in regeneration medicine. However, many limitations remain regarding the use of adult stem cells in clinical applications, including poor cell survival and low treatment efficiency. We describe an innovative three-dimensional cell mass (3DCM) culture that is based on cell adhesion (basic fibroblast growth factor-immobilized substrate) and assess the therapeutic potential of 3DCMs composed of human adipose tissue-derived stromal cells (hASCs). METHODS: For formation of a 3DCM, hASCs were cultured on a substrate with immobilized fibroblast growth factor-2. The angiogenic potential of 3DCMs was determined by immunostaining, fluorescence-activated cell sorting and protein analysis. To evaluate the vasculature ability and improved treatment efficacy of 3DCMs, the 3DCMs were intramuscularly injected into the ischemic limbs of mice. RESULTS: The 3DCMs released various angiogenic factors (eg, vascular endothelial growth factor and interleukin-8) and differentiated into vascular cells within 3 days in normal medium. Blood vessel and tissue regeneration was clearly observed through visual inspection in the 3DCM-injected group. hASC injection slowed limb necrosis after treatment, but 50% of the mice ultimately had limb loss within 28 days. Most mice receiving 3DCMs had limb salvage (89%) or mild limb necrosis (11%). CONCLUSIONS: 3DCM culture promotes the efficient vascular differentiation of stem cells, and 3DCM transplantation results in the direct vascular regeneration of the injected cells and an improved therapeutic efficacy.

Therapeutic angiogenesis of three-dimensionally cultured adipose-derived stem cells in rat infarcted hearts.

BACKGROUND AIMS: To successfully treat myocardial infarction (MI), blood must be resupplied to the ischemic myocardium by inducing angiogenesis. Many studies report enhanced angiogenesis using stem cells; however, the therapeutic efficacy of cell transplant remains low because transplanted cells may not survive, be retained at the site of transplant, or develop into vascular tissue. In this study, we assessed the therapeutic potential of three-dimensional cell masses (3DCM) composed of human adipose-derived stem cells (hASC) in a rat MI model. METHODS: For formation of 3DCM, hASC were cultured on a substrate with immobilized fibroblast growth factor 2. The morphology and phenotypes of 3DCM were analyzed 1 day after culture. The cells (hASC and 3DCM, 5 × 10(5) cells) were injected into ischemic regions after ligation of the left coronary artery (n = 6 in each group). Cell retention ratio, therapeutic efficacy and vascularization were evaluated 4 weeks after transplant. RESULTS: A spheroid-type 3DCM, which included vascular cells (CD34(+)/CD31(+)/KDR(+)/α-SMA(+)) with high production of human vascular endothelial growth factor, was obtained. Infarct size and cardiomyocyte apoptosis were reduced in the 3DCM-injected group compared with the hASC-injected group. The retention ratio of hASC was 14-fold higher in the 3DCM-injected group. Many transplanted cells differentiated into endothelial and smooth muscle cells and formed vascular networks incorporated into host vessels. CONCLUSIONS: Transplant of 3DCM may be useful for angiogenic cell therapy to treat MI.

Pd nanocrystals on WC as a synergistic electrocatalyst for hydrogen oxidation reactions.

Electrocatalysts for hydrogen oxidation reactions (HORs) are the key to renewable-energy technologies including fuel cells, hydrogen pumps, and water splitting. Despite the significant technological interest and tremendous efforts that have been made, development of hydrogen electrode catalysts with high activity at low cost remains a great challenge. Here, we report the preparation, characterization, and electrochemical properties of a hybrid material composed of Pd nanocrystals grown on spontaneously oxidized WC as a high-performance catalyst for the HOR. The Pd/WC hybrid exhibits enhanced catalytic activity compared to a carbon supported Pd (Pd/C) catalyst, making it a Pt-free, effective catalyst for the HOR. The remarkable catalytic activity arises from synergistic ligand effects between Pd and WC.

Simple Point-of-Care Nucleic Acid Amplification Test for Rapid SARS-CoV-2 Infection Diagnosis.

After three years of the SARS-CoV-2 pandemic, the demand for developing field-deployable point-of-care (PoC) molecular diagnostic tests has increased. Although RT-qPCR is the molecular diagnostic gold standard and is accurate, it is not readily applied to point-of-care testing (POCT). Meanwhile, rapid diagnostic kits have the disadvantage of low sensitivity. Recently, rapid isothermal nucleic acid amplification technology has emerged as an alternative for rapid diagnosis. Here, we developed a rapid SARS-CoV-2 reverse transcription loop-mediated isothermal amplification (RT-LAMP)-lateral flow assay (LFA) kit. This kit includes a Chelex-100/boiling nucleic acid extraction device and a one-step amplification detection apparatus capable of performing the entire process, from RNA extraction to detection, and diagnosing SARS-CoV-2 infection within 40 min without contamination. The detection limits of the rapid SARS-CoV-2 RT-LAMP-LFA kit were 100 plaque-forming units (PFUs) mL-1 and 10-1 PFU mL-1 for RNA samples extracted using the Chelex-100/boiling nucleic acid extraction device and commercial AdvansureTM E3 system, respectively. The sensitivity and specificity of the rapid SARS-CoV-2 RT-LAMP-LFA kit were 97.8% and 100%, respectively. Our SARS-CoV-2 RT-LAMP-LFA kit exhibited high sensitivity and specificity within 40 min without requiring laboratory instruments, suggesting that the kit could be used as a rapid POC molecular diagnostic test for SARS-CoV-2.

Increased Anti-Allergic Effects of Secretome of Low-Level Light Treated Tonsil-Derived Mesenchymal Stem Cells in Allergic Rhinitis Mouse Model.

BACKGROUND: Low-level light therapy (LLLT) is widely used for the photobiomodulation of cell behavior. Recent studies have shown that LLLT affects the proliferation and migration of various types of mesenchymal stem cells (MSCs). However, there is a lack of studies investigating the effect of LLT on enhancing the immunomodulatory properties of tonsil-derived MSCs (T-MSCs). OBJECTIVE: The aim of this study was to investigate the immunomodulatory effects of conditioned media from T-MSCs (T-MSCs-CM) treated with LLLT in allergic inflammation. METHODS: We isolated T-MSCs from human palatine tonsils and evaluated the ingredients of T-MSCs-CM. The effect of T-MSCs-CM treated with LLLT was evaluated in a mouse model of allergic rhinitis (AR). We randomly divided the mice into four groups (negative control, positive control, T-MSCs-CM alone, and T-MSCs-CM treated with LLLT). To elucidate the therapeutic effect, we assessed rhinitis symptoms, serum immunoglobulin (Ig), the number of inflammatory cells, and cytokine expression. RESULTS: We identified increased expression of immunomodulatory factors, such as HGF, TGF-ß, and PGE, in T-MSCs-CM treated with LLLT, compared to T-MSCs-CM without LLLT. Our animal study demonstrated reduced allergic symptoms and lower expression of total IgE and OVA-specific IgE in the LLLT-treated T-MSCs-CM group compared to the AR group and T-MSCs-CM alone. Moreover, we found that T-MSCs-CM treated with LLLT showed significantly decreased infiltration of eosinophils, neutrophils, and IL-17 cells in the nasal mucosa and reduced IL-4, IL-17, and IFN-γ expression in OVA-incubated splenocytes compared to the AR group. CONCLUSIONS: The present study suggests that T-MSCs-CM treated with LLLT may provide an improved therapeutic effect against nasal allergic inflammation than T-MSCs-CM alone.