Sensing with MXenes: Progress and Prospects Ho, Dong Hae; Choi, Yoon Young; Jo, Sae Byeok ...
Advanced materials (Weinheim),
11/2021, Letnik:
33, Številka:
47
Journal Article
Recenzirano
Various fields of study consider MXene a revolutionary 2D material. Particularly in the field of sensors, the metal‐like high electrical conductivity and large surface area of MXenes are desirable ...characteristics as an alternative sensor material that can transcend the boundaries of existing sensor technology. This critical review provides a comprehensive overview of recent advances in MXene‐based sensor technology and a roadmap for commercializing MXene‐based sensors. The existing sensors are systematically categorized as chemical, biological, and physical sensors. Each category is then classified into various subcategories depending on the electrical, electrochemical, structural, or optical sensing mechanism, which are the four fundamental working mechanisms of sensors. Representative structural and electrical approaches for boosting the performance of each category are presented. Finally, factors that hinder commercializing MXene‐based sensors are discussed, and several breakthroughs in realizing commercially available MXene‐based sensors are suggested. This review provides broad insights pertaining to previous and existing MXene‐based sensor technology and perspectives on the future generation of low‐cost, high‐performance, and multimodal sensors for soft‐electronics applications.
Metal‐like electrical conductivity and a large MXene surface area are desirable characteristics for alternative sensor material. An overview of recent advances in MXene‐based sensor technology that utilize the beneficial properties of MXenes is offered. Insights into low‐cost, high‐performance MXene‐based sensors for next generation soft‐electronics applications are also provided.
Blue emissive perovskites can be prepared by incorporating chlorine into bromine‐based perovskites to tune their bandgap. However, mixed‐halide perovskites exhibit intrinsic phase instability, ...particularly under electrical potential, owing to halide migration. To achieve high‐performance blue perovskite‐based light‐emitting diodes (PeLEDs) with operational stability, organic ammonium cations are used for passivating the anionic defects of the CsPbBr2Cl film. Diphenylpropylammonium chloride (DPPACl), used as a passivating agent, successfully prevents the spectral instability of blue PeLEDs by passivating the Cl− vacancies. Consequently, the blue PeLED prepared with this passivating agent delivers excellent device performance with a maximum external quantum efficiency of 3.03%. Moreover, upon tuning the DPPACl concentration, the PeLED emits stably in the deep‐blue spectral region (464 nm) with a half‐life time of 420 s. Thus, the use of organic ammonium cation as a passivating agent is an effective strategy for developing high‐performance blue PeLEDs with operational stability.
The introduction of an appropriate passivating agent into the perovskite film is an effective technique for preventing the halide migration of mixed‐halide perovskites to develop high‐performance blue perovskite light emitting diodes (PeLEDs) with spectral stability. The PeLED with 60% diphenylpropylammonium chloride shows stable emission in the deep‐blue spectral region (464 nm) with a maximum external quantum efficiency of 1.92%.
Under endoplasmic reticulum (ER)‐stress conditions, the unfolded protein response (UPR) generates a defense mechanism in mammalian cells. The regulation of UPR signaling is important in oocyte ...maturation, embryo development, and female reproduction of pigs. Recent studies have shown that melatonin plays an important role as an antioxidant to improve pig oocyte maturation. However, there is no report on the role of melatonin in the regulation of UPR signaling and ER‐stress during in vitro maturation (IVM) of porcine oocytes. Therefore, the objective of this study was to investigate the antioxidative effects of melatonin on porcine oocyte maturation through the regulation of ER‐stress and UPR signaling. We investigated the changes in the mRNA/protein expression levels of three UPR signal genes (Bip/Grp78, ATF4, P90/50ATF6, sXbp1, and CHOP) on oocytes, cumulus cells, and cumulus‐oocyte complexes (COCs) during IVM (metaphase I; 22 hours and metaphase II; 44 hours) by Western blot and reverse transcription‐polymerase chain reaction analysis. Treatment with the ER‐stress inducer, tunicamycin (Tm), significantly increased expression of UPR markers. Additionally, cumulus cell expansion and meiotic maturation of oocytes were reduced in COCs of Tm‐treated groups (1, 5, and 10 μg/mL). We confirmed the reducing effects of melatonin (0.1 μmol/L) on ER‐stress after pretreatment with Tm (5 μg/mL; 22 hours) in maturing COCs. Addition of melatonin (0.1 μmol/L) to Tm‐pretreated COCs recovered meiotic maturation rates and expression of most UPR markers. In conclusion, we confirmed a role for melatonin in the modulation of UPR signal pathways and reducing ER‐stress during IVM of porcine oocytes.
Salivary glands that produce and secrete saliva, which is essential for lubrication, digestion, immunity, and oral homeostasis, consist of diverse cells. The long-term maintenance of diverse salivary ...gland cells in organoids remains problematic. Here, we establish long-term murine and human salivary gland organoid cultures. Murine and human salivary gland organoids express gland-specific genes and proteins of acinar, myoepithelial, and duct cells, and exhibit gland functions when stimulated with neurotransmitters. Furthermore, human salivary gland organoids are established from isolated basal or luminal cells, retaining their characteristics. Single-cell RNA sequencing also indicates that human salivary gland organoids contain heterogeneous cell types and replicate glandular diversity. Our protocol also enables the generation of tumoroid cultures from benign and malignant salivary gland tumor types, in which tumor-specific gene signatures are well-conserved. In this study, we provide an experimental platform for the exploration of precision medicine in the era of tissue regeneration and anticancer treatment.
For resolving toxicity issues of Pb‐based perovskites, Sn‐based perovskites have been widely studied as a promising alternative due to similar valence electron configuration between Sn2+ and Pb2+. ...However, desired Sn2+ in the precursor solution and film is easily oxidized to Sn4+, causing detrimental Sn vacancies and impurities in the films. Unfortunately, dimethyl sulfoxide, a ubiquitously used Lewis base for the fabrication of high‐quality perovskite thin films via the adduct approach, further accelerates the oxidation of Sn2+ in the precursor solution. Herein, N,N′‐dimethylpropyleneurea (DMPU) is proposed as an alternative Lewis base for the fabrication of high‐quality Sn‐based perovskite thin films. The strongly coordinating Lewis base DMPU is shown to suppress the oxidation of Sn2+ in the precursor solution while promoting growth of uniform and highly crystalline thin films. The PEA2SnI4 perovskite light emitting diode (PeLED) based on DMPU demonstrates dramatically improves luminance (L): a more than sixfold enhanced external quantum efficiency (EQE) and better operational stability than those of the device fabricated without DMPU. The optimum PeLED based on DMPU achieves a maximum L and EQE of 68.84 cd m−2 and 0.361%, respectively. This study provides an important methodological base for studying Sn perovskites for development of high‐performance and eco‐friendly PeLEDs.
By adopting Lewis bases with varying coordinating ability, interplays between the coordinating ability of the Lewis base and tin halide perovskite film quality is unraveled. The strongly coordinating N,N′‐dimethylpropyleneurea suppresses oxidation of Sn2+ in the precursor solution while promoting growth of uniform and highly crystalline Sn perovskite thin films for achieving high‐performance lead‐free perovskite light emitting diodes.
Introduction
Exercise training is recommended for improving health and protecting against the development of metabolic and cardiovascular pathologies. Combined resistance and aerobic exercise ...training (CRAE) has been shown to provide unique benefits in older adults with cardiovascular diseases.
Purpose
We sought to determine the beneficial effects of CRAE in adolescent girls who are obese and hyperinsulinemic.
Methods
Forty adolescent girls who are obese (age 14.7 ± 1 years; BMI 30 ± 2) were randomly assigned to a “no exercise” (CON
n
= 20) or combined exercise group (EX n = 20). The EX group performed resistance and aerobic exercise for 12 weeks, 5 times per week. Exercise intensity was increased gradually, from 40 to 70% of heart rate reserve (HRR), every 4 weeks. The brachial-ankle pulse wave velocity (BaPWV), blood pressure (BP), heart rate (HR), blood leptin, adiponectin levels, and body composition were measured before and after the 12-week intervention.
Results
We observed that CRAE effectively reduced the body fat percentage, body weight, and waist circumference in the EX group (
p
< 0.05). After 12 weeks of training, subjects in the CRAE group maintained appropriate leptin and adiponectin levels and showed positive improvements of blood insulin, glucose, and insulin resistance parameters relative to baseline and to the CON group (
p
< 0.05).
Conclusion
CRAE is a useful therapeutic method to alleviate metabolic risk factors in adolescent girls who are obese and hyperinsulinemic.
Diesel exhaust particles (DEP) are a major source of air pollution. Nasal fibroblasts are known to produce various cytokines and chemokines. The aim of this study was to evaluate DEP-induced ...cytokines and chemokines in nasal fibroblasts and to identify the signaling pathway involved.
A cytokine and chemokine array performed after stimulation of nasal fibroblasts with DEP revealed that levels of IL-6 and IL-8 were increased most significantly among various cytokines and chemokines. RT-PCR and ELISA were used to determine the mRNA and protein expression levels of IL-6 and IL-8. Signaling pathways of p-38, Akt, and NF-κB were analyzed by western blotting, luciferase assay, and ELISA. Organ cultures of nasal interior turbinate were also developed to demonstrate the ex vivo effect of DEP on the expression of IL-6 and IL-8 and the associated signaling pathway.
DEP increased the expressions of IL-6 and IL-8 in nasal fibroblasts at mRNA and protein levels. DEP induced phosphorylation of p38, Akt, and NF-κB, whereas inhibitors of p38, Akt, and NF-κB blocked these phophorylations and the expressions of IL-6 and IL-8. These findings were also observed in ex vivo organ culture of nasal inferior turbinate.
DEP induces expression of IL-6 and IL-8 via p38, Akt, and NF-κB signaling pathways in nasal fibroblasts. This finding suggests that air pollution might induce or aggravate allergic rhinitis or chronic rhinosinusitis.
To examine whether a JAK inhibitor regulates functional responses of human salivary gland epithelial cells (SGECs) and disease parameters in an animal model of Sjögren's syndrome (SS).
Common ...differentially expressed genes (DEGs) were analyzed among peripheral blood mononuclear cells from patients with primary SS and other data sets, using blood and SG tissue. Validation of expression in SGs was analyzed by focus score. Inhibition of messenger RNA expression of DEGs and BAFF by filgotinib was analyzed using reverse transcription-polymerase chain reaction in primary SGECs. SG organoid cultures were used to determine the association between DEGs and BAFF via knockdown using small interfering RNAs or to determine regulation of BAFF by JAK inhibitor. Filgotinib (1.5 mg/kg) was intraperitoneally injected into 8-week-old NOD/ShiLtJ mice 3 times per week to analyze manifestations of disease. Finally, STAT signaling was assessed in human and mouse SGECs.
Expression of the DEGs IFNG and BAFF increased in SGs from patients with primary SS, as assessed by focus score. There was a significant correlation between IFIT2 and BAFF expression. JAK inhibitor suppressed interferon (IFN)-induced transcription of DEGs and BAFF in human primary SGECs. Knockdown of DEGs or inhibition of JAK caused reduced secretion of BAFF in human SG organoid cultures. In addition, filgotinib-treated mice exhibited increased salivary flow rates and marked reductions in lymphocytic infiltration of SGs. JAK inhibitor regulated IFNα- and IFNγ-induced pSTAT-1
, pSTAT-3
, and protein inhibitor of activated STAT-3 (PIAS-3) in human SGECs as well as IFNγ-induced pSTAT-1
, pSTAT-3
, and PIAS-1 in mouse SGECs.
JAK inhibition controls aberrant activation of SGECs and may be a novel therapeutic approach for primary SS.
Following curative liver resection (LR), resectable tumor recurrence in patients with preserved liver function leads to deciding between a repeat LR and a salvage liver transplantation (LT), if a ...donor’s liver is available. This retrospective study compared survival outcomes and recurrence pattern following salvage living donor LT (LDLT) and repeat LR in patients with recurrent hepatocellular carcinoma (HCC). We reviewed the medical records of patients who underwent repeat LR (n = 163) or LDLT (n = 84) for recurrent HCC following curative resections, between January 2005 and December 2017 at a single institution. A 1:1 propensity score matching led to 42 patients per group. Disease‐specific and recurrence‐free survival were significantly better in the salvage LDLT group than in the repeat LR group (p = .042; HR = 2.40; 95% CI, 0.69–6.00 and p < .001; HR = 4.23; 95% CI, 2.05–8.71, respectively). Despite significant differences in recurrence patterns between the two groups (p = .019), the patient death rates, after recurrence, were similar for both groups (p = .760). This study indicates that salvage LDLT is superior to repeat LR for treating patients with transplantable, intrahepatic HCC recurrence, even in patients with Child‐Pugh class A liver cirrhosis.
Salvage living donor liver transplantation is superior to repeat liver resection to treat patients with transplantable, recurrent intrahepatic hepatocellular carcinoma, even in patients with Child–Pugh class A liver cirrhosis.
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