An experimental study with extracellular vesicles (EVs) from mesenchymal stem cell (MSC) of the epidural fat (EF) of the spine.
This study aims to isolate the exosomes from epidural fat-derived ...mesenchymal stem cells (EF-MSCs) and fully characterize the EF-MSC-EVs.
EF-MSCs were reported in 2019, and a few studies have shown the positive outcomes of using EF-MSCs to treat specific spine pathologies. However, MSCs have significant limitations for conducting basic studies or developing therapeutic agents. Although EVs are an emerging research topic, no studies have focused on EVs, especially exosomes, from EF and EF-MSCs.
In this study, we isolated the exosomes using the tangential flow filtration (TFF) system with exosome-depleted fetal bovine serum and performed the characterization tests via western blotting, reverse transcription-polymerase chain reaction, nanoparticle tracking analysis (NTA), and transmission electron microscopy.
In transmission electron microscopy, the exosome had a diameter of approximately 100-200 nm and had a spherical shape, whereas in the NTA, the exosome had an average diameter of 142.8 nm with a concentration of 1.27×1010 particles/mL. The flow cytometry analysis showed the expression of CD63 and CD81. The western blotting analysis showed the positive markers.
These findings showed that isolating the exosomes via TFF resulted in high-quality EF-MSC exosome yield. Further studies with exosomes from EF-MSC are needed to evaluate the function and role of the EF tissue.
Extracellular vesicles (EVs) are generated and secreted by cells into the circulatory system. Stem cell-derived EVs have a therapeutic effect similar to that of stem cells and are considered an ...alternative method for cell therapy. Accordingly, research on the characteristics of EVs is emerging. EVs were isolated from human epidural fat-derived mesenchymal stem cells (MSCs) and human fibroblast culture media by ultracentrifugation. The characterization of EVs involved the typical evaluation of cluster of differentiation (CD antigens) marker expression by fluorescence-activated cell sorting, size analysis with dynamic laser scattering, and morphology analysis with transmission electron microscopy. Lastly, the secreted levels of cytokines and chemokines in EVs were determined by a cytokine assay. The isolated EVs had a typical size of approximately 30-200 nm, and the surface proteins CD9 and CD81 were expressed on human epidural fat MSCs and human fibroblast cells. The secreted levels of cytokines and chemokines were compared between human epidural fat MSC-derived EVs and human fibroblast-derived EVs. Human epidural fat MSC-derived EVs showed anti-inflammatory effects and promoted macrophage polarization. In this study, we demonstrated for the first time that human epidural fat MSC-derived EVs exhibit inflammatory suppressive potency relative to human fibroblast-derived EVs, which may be useful for the treatment of inflammation-related diseases.
A high-sensitivity, label-free method for detecting deoxyribonucleic acid (DNA) using solution-processed oxide thin-film transistors (TFTs) was developed. Double-crossover (DX) DNA nanostructures ...with different concentrations of divalent Cu ion (Cu2+) were immobilized on an In–Ga–Zn–O (IGZO) back-channel surface, which changed the electrical performance of the IGZO TFTs. The detection mechanism of the IGZO TFT-based DNA biosensor is attributed to electron trapping and electrostatic interactions caused by negatively charged phosphate groups on the DNA backbone. Furthermore, Cu2+ in DX DNA nanostructures generates a current path when a gate bias is applied. The direct effect on the electrical response implies that solution-processed IGZO TFTs could be used to realize low-cost and high-sensitivity DNA biosensors.
Trisilylamine (TSA), an exemplary chlorine and carbon-free commercial silylamine precursor, is well-known to induce improvements in the process and properties of silicon nitride (SiN
x
) thin films ...grown using atomic layer deposition (ALD). Herein, we report a TSA homolog, tris(disilanyl)amine (TDSA), as a novel chlorine and carbon-free precursor for the deposition of highly etch resistant SiN
x
thin films having a high growth rate at a low temperature (<300 °C) using plasma enhanced ALD (PEALD) with hollow cathode plasma (HCP). These improvements in PEALD SiN
x
using TDSA may be attributed to higher surface reactivity of the molecule enabled by weaker Si-N bonds, higher molecular polarity and the existence of reactive Si-Si bonds in the molecule. The performance of PEALD SiN
x
grown by TDSA has been compared with that of TSA, aminosilanes and chlorosilanes, and explained with the structure-property relationship of the molecule. TDSA grows SiN
x
film faster than TSA. Furthermore, the TDSA precursor produces SiN
x
films that have lower wet etch rate (WER) when compared to other silylamine precursors like TSA, or other types of silane precursors such as aminosilanes and chlorosilanes. We believe that the result, that TDSA-grown SiN
x
films exhibit lower WER than TSA-grown SiN
x
films, can be attributed to the abundance of Si in SiN
x
films, which thereby offers high resistance to a wet etch.
Trisilylamine homolog, tris(disilanyl)amine (TDSA), is introduced as a novel precursor for the deposition of highly etch resistant silicon nitride thin films having a high growth rate at a low temperature (<300 °C) using plasma enhanced ALD process.
DBA/2 mice are a well-known animal model for hearing loss developed due to intrinsic properties of these animals. However, results on the phenotype of hearing loss in DBA/2 mice have been mainly ...reported at an early stage in mice aged ≤7 weeks. Instead, the present study evaluated the hearing ability at 5, 13, and 34 weeks of age using DBA/2korl mice. Auditory brainstem response test was performed at 8-32 KHz at 5, 13, and 34 weeks of age, and hearing loss was confirmed to be induced in a time-dependent manner. In addition, histopathological evaluation at the same age confirmed the morphological damage of the cochlea. The findings presented herein are the results of the long-term observation of the phenotype of hearing loss in DBA/2 mice and can be useful in studies related to aging-dependent hearing loss.
In this work, a nano-polycrystalline Ag-doped ZnO-based threshold switching (TS) selector via a facile co-sputtering technique is investigated without using an Ag active metal layer. The effects of ...the Ag concentration with respect to OFF-state leakage current (Ioff) were studied, and the results demonstrate that by regulating the Ag doping concentration in the switching layer (SL), an electroforming-free switching with an Ion/Ioff ratio of ∼108 could be achieved, having an extremely low Ioff value of ∼10−13 A. Furthermore, cycling endurance can also be improved as the formation of a laterally thick and stable filament does not happen promptly with consequent measurements when there is a limited amount of Ag in the SL. The selector device performance enhancement is attributed to the doping-based polycrystalline structure that facilitates enhanced control on filament formation due to the restricted availability and anisotropic diffusion of Ag ions in the polycrystalline ZnO SL, thereby trimming down the overall stochasticity during metallic filament growth. The present study demonstrates that a doping-based polycrystalline SL structure can be implemented in a selector device to augment TS characteristics, i.e., device variances and cycling endurance for adoption in ultra-high density memory applications.
Low-temperature solution-processed In–Zn–O (IZO) thin-film transistors (TFTs) exhibiting a favorable microenvironment for electron transfer by adsorbed artificial deoxyribonucleic acid (DNA) have ...extraordinary potential for emerging flexible biosensor applications. Superb sensing ability to differentiate even 0.5μL of 50nM DNA target solution was achieved through using IZO TFTs fabricated at 280°C. Our IZO TFT had a turn-on voltage (Von) of −0.8V, on/off ratio of 6.94×105, and on-current (Ion) value of 2.32×10−6A in pristine condition. A dry-wet method was applied to immobilize two dimensional double crossover tile based DNA nanostructures on the IZO surface, after which we observed a negative shift of the transfer curve accompanied by a significant increase in the Ion and degradation of the Von and on/off ratio. As the concentration of DNA target solution increased, variances in these parameters became increasingly apparent. The sensing mechanism based on the current evolution was attributed to the oxidation of DNA, in which the guanine nucleobase plays a key role. The sensing behavior obtained from flexible biosensors on a polymeric substrate fabricated under the identical conditions was exactly analogous. These results compare favorably with the conventional field-effect transistor based DNA sensors by demonstrating remarkable sensitivity and feasibility of flexible devices that arose from a different sensing mechanism and a low-temperature process, respectively.
•For practical use of solution-processed In–Zn–O (IZO) thin film transistor (TFT) as a biosensor, achieving remarkable sensitivity and feasibility of flexible devices is strongly desired.•Here we report low-temperature solution-processed IZO TFTs with a construction temperature of only 280°C, which is a decisive factor in flexible devices being able to compensate for the aforementioned limitations for the first time.•These findings can enhance the applicability of IZO TFTs as a next generation biosensor.
To broaden the availability and application of metal–oxide (M–O)-based optoelectronic devices, we suggest heterogeneous phototransistors composed of In–Ga–Zn–O (IGZO) and methylammonium lead iodide ...(CH3NH3PbI3) layers, which act as the amplifier layer (channel layer) and absorption layer, respectively. These heterogeneous phototransistors showed low persistence photocurrent compared with IGZO-only phototransistors and exhibited high photoresponsivity of 61 A/W, photosensitivity of 3.48 × 106, detectivity of 9.42 × 1010 Jones, external quantum efficiency of 154% in an optimized structure, and high photoresponsivity under water exposure via the deposition of silicon dioxide as a passivation layer. On the basis of these electrical results and various analyses, we determined that CH3NH3PbI3 could be activated as a light absorption layer, current barrier, and plasma damage blocking layer, which would serve to widen the range of applications of M–O-based optoelectronic devices with high photoresponsivity and reliability under visible light illumination.
Al-base amorphous/nanocrystalline bulk alloy rods composed of Al–10Ni–6Ce (numbers indicate at.%) matrix alloy and Al–4Fe–0.6Mo–1.1V–0.3Zr alloy particles (volume fraction
=
0.3) were fabricated by a ...powder forging process. The starting materials were rapidly quenched, powder-shaped amorphous Al–10Ni–6Ce alloy and nanocrystalline Al–4Fe–0.6Mo–1.1V–0.3Zr alloy. The amorphous alloy powders were prepared by the pulverization of melt-spun ribbons, and the nanocrystalline alloy powders were fabricated by using a gas atomization technique. The powder forging process involved pre-compaction of the amorphous/crystalline powder mixtures by cold pressing and subsequent forging at temperatures ranging from 623 to 773
K with a pressure of 0.66
GPa and a strain rate of 10
−2
s
−1 to produce the rod-shaped bulk hybrid alloys having a diameter of 10
mm. Bulk monolithic Al–10Ni–6Ce alloys having the same shape were also fabricated by using a similar process to that used for the hybrid ones. Fully dense bulk rods with a porosity of less than 2% were achieved for all of the forged monolithic and hybrid alloys. A remarkably high compressive strength of about 1.2
GPa along with a compressive plastic strain of 1% was obtained at room temperature for the bulk hybrid specimen forged at 648–673
K. In contrast, the bulk monolithic specimen forged at 648–723
K did not exhibit any compressive plastic strain, although it possessed a very high compressive strength of approximately 1.34
GPa.
Increasing interest in the development of alternative energy storage technologies has led to efforts being taken to improve the energy density of dielectric capacitors with high power density. ...However, dielectric polymer materials still have low energy densities because of their low dielectric constant, whereas Pb-based materials are limited by environmental issues and regulations. Here, the energy storage behaviors of atomic layer-deposited Hf
Zr
O
( X = 0-1) thin films (10 nm) and the phase transformation mechanism associated with an enhancement of their energy density are reported using unipolar pulse measurements. Based on electrical and material characterization, the energy density and energy efficiency are dependent on the Zr content, and stress-induced crystallization by the encapsulating Hf
Zr
O
films with TiN top electrodes prior to annealing can enhance the energy density (up to 47 J/cm
at a small voltage value of 3.5 MV/cm) while minimizing energy loss even at low process temperatures (400 °C). This work will facilitate the realization of Hf
Zr
O
-based capacitors for lead-free electrostatic energy storage applications.
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