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1.
Artigo em Inglês | MEDLINE | ID: mdl-33684880

RESUMO

Chondrosarcoma is the 2nd most frequent bone sarcoma. In this study, the metabolic profiling of human chondrosarcoma SW-1353 cell line was investigated for the first time. To obtain more precise information about the metabolites from chondrosarcoma cells, pretreatment methods including washing steps/solvents, harvesting conditions, and extraction protocols for chondrosarcoma SW-1353 cells were evaluated in the context of metabolite profiling by GC-MS technique. In addition, a total of 32 representative metabolites (related to amino acid metabolism, TCA cycle, glycolysis, and fatty acid metabolism) were quantitatively determined. We found that a fast water rinse step before metabolic quenching, may reduce the contaminants and improve sensitivity. Trypsin/ethylene diamine tetraacetic acid treatment led to a large amount of metabolite leakage, which was not suitable for metabolomics research. Methanol was selected as a more suitable extraction solvent among four extraction approaches applied to SW-1353 cells. The final protocol can provide a simple, robust, and reproducible method to obtain precise information about the metabolites from chondrosarcoma cells, which is helpful to further understand the chondrosarcoma cell physiology and the mechanism of drug resistance in this disease, from the perspective of metabolomics.

2.
Acta Pharmacol Sin ; 2021 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-33782542

RESUMO

Checkpoint kinase 1 inhibitors (CHK1i) have shown impressive single-agent efficacy in treatment of certain tumors, as monotherapy or potentiators of chemotherapy in clinical trials, but the sensitive tumor types and downstream effectors to dictate the therapeutic responses to CHK1i remains unclear. In this study we first analyzed GDSC (Genomics of Drug Sensitivity in Cancer) and DepMap database and disclosed that hematologic malignancies (HMs) were relatively sensitive to CHK1i or CHK1 knockdown. This notion was confirmed by examining PY34, a new and potent in-house selective CHK1i, which exhibited potent anti-HM effect in vitro and in vivo, as single agent. We demonstrated that the downregulation of c-Myc and its signaling pathway was the common transcriptomic profiling response of sensitive HM cell lines to PY34, whereas overexpressing c-Myc could partially rescue the anticancer effect of PY34. Strikingly, we revealed the significant correlations between downregulation of c-Myc and cell sensitivity to PY34 in 17 HM cell lines and 39 patient-derived cell (PDC) samples. Thus, our results demonstrate that HMs are more sensitive to CHK1i than solid tumors, and c-Myc downregulation could represent the CHK1i efficacy in HMs.

3.
J Pharm Biomed Anal ; 198: 114014, 2021 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-33765511

RESUMO

Jinlingzi San (JLZS), composed of Fructus Toosendan (FT) and Rhizoma Corydalis (RC), is a classical traditional Chinese medicine prescription for regulating Qi to relieve pain. The present study investigated the pharmacokinetic compatibility of FT and RC in JLZS. A fast, selective and sensitive UPLC-MS/MS method for simultaneous determination of one limonoid (toosendanin), four tertiary alkaloids (corydaline, tetrahydropalmatine, tetrahydrocoptisine, tetrahydroberberine) and two quaternary alkaloids (palmatine, dehydrocorydaline) in rat plasma was established and fully validated. The plasma samples were pretreated by a fast protein precipitation and chromatographed using a 1.7-µm C18 column and 0.1 % formic acid-water and acetonitrile via gradient elution with a run time of 3.7 min. Multiple reaction monitoring mode with positive electrospray ionization was adopted to detect the analytes and internal standard (diphenhydramine). The lower limits of quantification were 0.08-3.09 ng/mL using only 50 µL of plasma sample. Using the proposed method, the pharmacokinetic differences of seven bioactive components in rats after administration of JLZS and the single herb (FT or RC) were investigated. The results showed that the elimination of toosendanin and alkaloids decreased significantly in the JLZS group (p < 0.05) compared with the single herb group, and the exposure of the alkaloids increased in some degree. The study demonstrated the synergistic effect of combining FT with RC on the pharmacokinetics of seven bioactive components and provided new information for a better understanding of the compatibility mechanism of JLZS.

4.
Drug Des Devel Ther ; 15: 769-786, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33654382

RESUMO

Background: Anxiety disorders (ADs) are the most prevalent mental disorders worldwide. Stress-induced activation of the hypothalamic-pituitary-adrenal (HPA) axis and dysbiosis of gut microbiota seem to contribute to the onset of ADs. This study was designed to investigate the ameliorative effect of volatile oil of Zanthoxylum bungeanum (VOZB) on chronic unpredictable stress (CUS) induced anxiety behavior, as well as the altered HPA axis and gut microbiota. Methods: Experimental rats were exposed to the CUS for 14 consecutive days. Meanwhile, VOZB was administered at doses of 50, 100 and 200 mg/kg/day for 14 days. The anxiety behavior was evaluated by elevated plus-maze (EPM) and open field (OF). The protein expressions and mRNA levels of corticotropin-releasing hormone (CRH) and glucocorticoid receptor (GR) in hypothalamus was determined, as well the hormone levels of HPA axis in serum. Furthermore, gut microbiota was detected by16S rRNA gene sequencing. The chemical constituents of VOZB were identified by GC-MS analysis. Results: VOZB treatment (100 and 200 mg/kg/day) increased the ratio of open-arm entries and time in EPM test, as well as the central zone entries and time in OF test. Moreover, VOZB treatment reduced the protein expressions and mRNA levels of CRH, but elevated those of GR in hypothalamus. Similarly, the hormone levels of the HPA axis in serum were decreased by VOZB treatment. Besides, VOZB treatment restored the CUS-induced dysbiosis of gut microbiota, raising the Sobs and Chao indexes, inhibiting Lachnospiraceae, but facilitating Bacteroidales_S24-7_group, Lactobacillaceae, and Prevotellaceae. Additionally, Sobs and Chao indexes were negatively correlated to the serum corticosterone and CRH levels. Conclusion: VOZB showed an ameliorative effect on CUS-induced anxiety behavior, potentially via inhibiting activation of the HPA axis and restoring the dysbiosis of gut microbiota, thus improving the stress-induced abnormality of the microbiota-gut-brain axis.

5.
Insects ; 12(2)2021 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-33668407

RESUMO

Holotrichia parallela (Coleoptera: Scarabaeidae: Melolonthinae) is a notorious pest of many crops, especially peanuts. In this study, volatiles from peanut plants were analyzed using both gas chromatographic-electroantennographic detection (GC-EAD) and gas chromatography/mass spectrometry (GC/MS) techniques, and tested for adult attraction with field trapping bioassays in Hebei Province, China. GC-EAD analyses indicated that H. parallela antennae strongly responded to twelve GC peaks, including eight identified compounds, (Z)-ß-ocimene, hexanal, 6-methyl-5-hepten-2-one, nonanal, dihydromyrcenol, linalool, ß-caryophyllene, methyl salicylate, and four unidentified compounds. When tested individually in field conditions from 24 to 31 July, 2020, ß-caryophyllene and hexanal significantly attracted both sexes of H. parallela, whereas all other compounds were unattractive. A blend of ß-caryophyllene and hexanal at a ratio of 2:1, close to the natural ratio of these two compounds from the intact peanut plant, was most attractive to the beetles. The remaining identified compounds, (Z)-ß-ocimene, 6-methyl-5-hepten-2-one, nonanal, dihydromyrcenol, linalool, and methyl salicylate had no synergistic effects on H. parallela attraction when tested in combination with the blend of ß-caryophyllene and hexanal. These results demonstrated that ß-caryophyllene and hexanal in the volatiles from peanut plants have strong attraction to H. parallela. These two compounds have the potential to be used for monitoring H. parallela and its management programs.

6.
Zhongguo Zhong Yao Za Zhi ; 46(4): 951-965, 2021 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-33645102

RESUMO

The Qinling-Daba Mountains area is the main producing areas of Gynostemma longipes for medicinal usage, and samples of wild whole plants in Pingli, Shaanxi Province and Qingchuan, Sichuan Province were collected. The ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(UHPLC-Q-TOF-MS~E) was used to profile the chemical compositions and analyze the similarities and differences of G. longipes samples in these areas. Based on the accurate molecular weight and fragment information obtained from Q-TOF-MS~E, the structures of the main components were identified by combining with the mass spectra, chromatographic behaviors of reference standards and related literatures. The results showed that the components of wild G. longipes from different places among Qinling-Daba Mountains area were similar. Forty-five chemical components were identified in the whole plant of G. longipes from Pingli, Shaanxi Province, including 43 triterpenoid saponins and 2 flavonoids which contain all main peaks in its fingerprint. The main components are dammarane-type triterpenoid saponins, such asgypenoside ⅩLⅨ, gypenoside A and its malonylated product of glycosyl.


Assuntos
Medicamentos de Ervas Chinesas , Saponinas , Cromatografia Líquida de Alta Pressão , Gynostemma , Espectrometria de Massas
7.
Cancer Med ; 10(7): 2509-2522, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33704935

RESUMO

Prostate cancer-associated fibroblasts (prostate CAFs) are essential components of the tumor microenvironment and can promote tumor progression through their immunosuppressive functions. MPSSS, a novel polysaccharide purified from Lentinus edodes, has been reported to have anti-tumor activity. MPSSS could also inhibit the immunosuppressive function of prostate CAFs, which has been demonstrated through that the secretome of MPSSS-treated prostate CAFs could inhibit the proliferation of T cells. However, how the secretome of MPSSS-treated prostate CAFs influence prostate cancer progression is still unclear. Interestingly, we found that the low molecular weight (3-100kD) secretome of prostate CAFs (lmwCAFS) could promote the growth of PC-3 cells, while that of MPSSS-treated prostate CAFs (MT-lmwCAFS) could inhibit their growth. We carried out comparative secretomic analysis of lmwCAFS and MT-lmwCAFS to identify functional molecules that inhibit the growth of PC-3 cells, and proteomic analysis of lmwCAFS-treated PC-3 cells and MT-lmwCAFS-treated PC-3 cells to investigate the underlying molecular mechanism. These analyses suggest that TGF-ß3 from MT-lmwCAFS may inhibit the growth of PC-3 cells. The validated experiments revealed that TGF-ß3 from MT-lmwCAFS activated p21 expression in PC-3 cells by regulating the FoxO pathway thereby inducing G0/G1 cell cycle arrest of PC-3 cells. Overall, our data demonstrated that MPSSS reversed the ability of prostate CAFs to suppress the cell viability of PC-3 cells, which might provide a potential therapeutic strategy to prevent prostate cancer progression.

9.
Biochim Biophys Acta Gene Regul Mech ; 1864(3): 194688, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33556623

RESUMO

The PWWP domain was first identified in the HDGF protein family and named after the conserved Proline-Tryptophan-Tryptophan-Proline motif in WHSC1. The PWWP domain-containing proteins play important roles in different biological processes, such as DNA replication, transcription, DNA repair, pre-mRNA processing by recognizing methylated histone and dsDNA simultaneously. Recently, how the HDGF family of PWWP domains recognize histone H3K36me3-modified nucleosome has been reported. In order to better understand the interactions between the PWWP domain and dsDNA, we carried out family-wide characterization of dsDNA binding abilities of human PWWP domains. Our binding assays confirmed that PWWP domains bind to dsDNA without sequence selectivity. Our crystal structure of the BRPF2 PWWP domain in complex with a 12-mer dsDNA reveals that the PWWP domain interacts with dsDNA by binding to its major groove, instead of the minor groove observed in the HDGF family of PWWP domains. Our study indicates that PWWP domains could bind to dsDNA in different modes.

10.
Molecules ; 26(4)2021 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-33578780

RESUMO

Cancer is a major factor threatening human health and life safety, and there is a lack of safe and effective therapeutic drugs. Intervention and prevention in premalignant process are effective ways to reverse carcinogenesis and prevent cancer from occurring. Plant natural products are rich in sources and are a promising source for cancer chemoprevention. This article reviews the chemopreventive effects of natural products, especially focused on polyphenols, flavonoids, monoterpene and triterpenoids, sulfur compounds, and cellulose. Meanwhile, the main mechanisms include induction of apoptosis, antiproliferation and inhibition of metastasis are briefly summarized. In conclusion, this article provides evidence for natural products remaining a prominent source of cancer chemoprevention.

11.
Endocr Pract ; 2021 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-33610810

RESUMO

OBJECTIVE: Active surveillance (AS) is a management alternative for patients with low risk papillary thyroid microcarcinoma (PTMC). To decide the best candidates for AS, clinicians can use a framework to classify PTMC patients as ideal, appropriate or inappropriate. The aim of this study is to explore the correlation of the framework categories and surgical pathology. METHODS: This was a multicenter retrospective study between 2014 and 2016. Totally 1997 patients who underwent thyroid surgery for the first time due to suspected PTMC and confirmed as PTMC by postoperative pathology were included. Consistence of a modified preoperative risk stratification and the pathologic condition were evaluated using consistency ratio and Kappa test. Stratified analysis was also performed to test consistency in different age groups. RESULTS: Based on the decision-making framework, 558 (27.9%) patients could receive AS. While 810 (40.6%) patients did not require immediate surgery according to the actual postoperative pathology. The sensitivity, false positive rate, specificity, false negative rate and consistency rate were 82.39%, 56.91%, 43.09%, 17.61% and 66.45% respectively. The Kappa value was 0.268. Stratified analysis showed that the sensitivity was 87.7% among patients between ages 18 and 59. In over 60 years group, the specificity was up to 87.5% but the sensitivity was low. CONCLUSIONS: The results of modified risk-stratified clinical decision-making framework do not have a high consistency with the postoperative results. However, the framework shows good effect in selecting patients for immediate surgery in the younger group and the ones for AS in the older group.

12.
Curr Med Imaging ; 2021 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-33602105

RESUMO

BACKGROUND AND AIMS: Coronavirus disease 2019 (COVID-19) pandemic has become a global health issue. This study aimed to explore the clinical characteristics and CT imaging features of patients with COVID-19 on admission. METHODS: Consecutive patients with laboratory-confirmed COVID-19 were retrospectively recruited to this study from January 2020 to March 2020. According to the disease severity status on admission, patients were divided into two groups, the common group and the severe group. RESULTS: Forty-four patients (F/M 20/24) confirmed with COVID-19 were enrolled in this study. The most common onset symptom was fever (90.9%), followed by cough (43.2%). As for the laboratory tests, common findings included increased C reactive protein (47.7%) and erythrocyte sedimentation rate (43.2%), and decreased lymphocyte (34.1%). Frequency of decreased lymphocyte count and increased lactate dehydrogenase were higher in the severe group (n=14) than in the common group (n=30). About 86% patients showed typical imaging findings of COVID-19 infection including ground-glass opacity with ill-defined margins, air bronchogram, interlobular septal thickening, and consolidation. Lesions mainly located peripherally and subpleurally with diffuse distribution and multiple lung lobes affected. CONCLUSION: Fever and cough are the most common onset symptoms of COVID-19. Increased C reactive protein and erythrocyte sedimentation rate were the most common laboratory findings. Typical signs of chest CT imaging of COVID-19 included ground-glass opacity with ill-defined margins, air bronchogram, interlobular septal thickening, and consolidation.

13.
Food Funct ; 12(2): 668-681, 2021 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-33410435

RESUMO

Duck egg white (DEW) is considered as an abandoned protein resource. For a higher-value utilization, preparation of immunomodulatory peptides from the extracted ovalbumin in DEW was explored. Among the hydrolysates catalyzed by five proteases, papain hydrolysate (PH) shows the highest degree of hydrolysis and the strongest immunomodulatory activity. PH could significantly enhance the phagocytic capacity and promote the NO, TNF-α, and IL-6 secretion of RAW 264.7 cells, involving toll-like receptor 2 and 4. After purification, nine identified peptides were synthesized to confirm the immunomodulatory effect, and five of them exhibit a strong activity. The peptide, TQIDKVVHFDKLPGF, presents the highest immunomodulatory activity. Moreover, the results of molecular docking indicate that nine peptides interacted with toll-like receptor 2 and 4 and all show good affinity. Furthermore, three peptides with high affinity and strong immune activity were selected for interaction site map analysis. Three peptides could form hydrogen bonds with the receptor and bind stably, which contributes to the immunomodulatory activity of the peptide. Results suggest that DEW can be a promising source of immunomodulatory peptides.

14.
Pharm Res ; 38(2): 347-359, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33469875

RESUMO

PURPOSE: To formulate a xanthan gum-containing linezolid ophthalmic solution (LZD-XG) as a new antibiotic treatment against ocular bacterial infection. METHODS: LZD-XG was prepared and evaluated for its in vitro/in vivo ocular tolerance, in vitro/in vivo antibacterial activity, and in vivo ocular penetration. RESULTS: The optimized LZD-XG exhibited good in vitro/in vivo eye tolerance. A prolonged ocular surface residence time of LZD-XG was observed after topical instillation, and the ocular permeation was significantly better for LZD-XG than fora linezolid (LZD) ophthalmic solution. The in vitro antimicrobial activity was significantly better with LZD-XG than with LZD. In vivo evaluation also confirmed a strong therapeutic treatment effect of LZD-XG, as it significantly improved the clinical symptoms, ameliorated the damage of Staphylococcus aureus to ocular tissues, lowered the colony forming unit counts in the cornea, and decreased the myeloperoxidase activity in the cornea. CONCLUSION: LZD-XG was deemed a viable ophthalmic solution against ocular bacterial infection due to its excellent in vitro and in vivo characterizations.

15.
Cell Mol Immunol ; 18(3): 632-643, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33500563

RESUMO

Stimulator of interferon genes (STING)-mediated innate immune activation plays a key role in tumor- and self-DNA-elicited antitumor immunity and autoimmunity. However, STING can also suppress tumor immunity and autoimmunity. STING signaling in host nonhematopoietic cells was reported to either protect against or promote graft-versus-host disease (GVHD), a major complication of allogeneic hematopoietic cell transplantation (allo-HCT). Host hematopoietic antigen-presenting cells (APCs) play key roles in donor T-cell priming during GVHD initiation. However, how STING regulates host hematopoietic APCs after allo-HCT remains unknown. We utilized murine models of allo-HCT to assess the role of STING in hematopoietic APCs. STING-deficient recipients developed more severe GVHD after major histocompatibility complex-mismatched allo-HCT. Using bone marrow chimeras, we found that STING deficiency in host hematopoietic cells was primarily responsible for exacerbating the disease. Furthermore, STING on host CD11c+ cells played a dominant role in suppressing allogeneic T-cell responses. Mechanistically, STING deficiency resulted in increased survival, activation, and function of APCs, including macrophages and dendritic cells. Consistently, constitutive activation of STING attenuated the survival, activation, and function of APCs isolated from STING V154M knock-in mice. STING-deficient APCs augmented donor T-cell expansion, chemokine receptor expression, and migration into intestinal tissues, resulting in accelerated/exacerbated GVHD. Using pharmacologic approaches, we demonstrated that systemic administration of a STING agonist (bis-(3'-5')-cyclic dimeric guanosine monophosphate) to recipient mice before transplantation significantly reduced GVHD mortality. In conclusion, we revealed a novel role of STING in APC activity that dictates T-cell allogeneic responses and validated STING as a potential therapeutic target for controlling GVHD after allo-HCT.

16.
J Pharm Biomed Anal ; 195: 113847, 2021 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-33358618

RESUMO

As a traditional Chinese medicine of invigorating the kidney, Cuscuta chinensis (CC) can be applied in improving the deficiency of kidney qi in menopausal women and regulating the level of estrogen. Previously, it was found that the ethanol extract of CC had an estrogen-like effect. In this study, the metabolic profile and metabolic pathways of rats in sham, ovariectomized model and CC groups were analyzed using UPLC-TOFMS-based metabolomics and the pattern recognition technology. The serum endogenouse metabolites could be well differentiated in different group, indicating significant differences of metabolic profiles. CC had an reverse adjustment effect on 14 differential metabolites of ovariectomized rats, including sinapyl alcohol, deoxycholic acid, prostaglandin B2, prostaglandin I2, dihydrosphingosine, choline, pentadecanoic acid, arachidonic acid, 1-stearoyl-Sn-Glycerol-3-Phosphocholine, palmitoleic acid, palmitic acid, vaccenic acid, oleic acid and stearic acid. Furthermore, these differential metabolites were categorized into several major pathways, such as biosynthesis of unsaturated fatty acids, lycerophospholipid metabolism and arachidonic acid metabolism. Therefore, it could be concluded that the estrogen-like effect of CC was related to the lipid metabolism to some extent. The research results provide useful help for the in-depth research and development of CC.

17.
Food Chem ; 334: 127475, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32688176

RESUMO

Although numerous types of organisms have been used to enrich selenium, a low-cost and efficient organism is yet to be identified. This study aimed to develop a new means of selenium enrichment using Tenebrio molitor larvae. Our results indicated that the total selenium content in larvae was increased 83-fold to 54.21 ± 1.25 µg/g, and of this content, organic selenium accounted for over 97% after feeding the larvae with 20 µg/g of sodium selenite. Selenium was distributed unequally in the protein fraction with following order: alkali-soluble protein-bound selenium (36.32%) > salt-soluble protein-bound selenium (19.41%) > water-soluble protein-bound selenium (17.03%) > alcohol-soluble protein-bound selenium (3.21%). Additionally, 81% of the selenium within the soluble proteins was distributed in subunits possessing molecular weights of <40 kDa. After hydrolysis by alcalase, the protein hydrolysate of selenium-enriched larvae possessing 75% selenium recovery exhibited stronger antioxidant and immunoregulatory activities than those of regular larvae.


Assuntos
Antioxidantes/farmacologia , Fatores Imunológicos/farmacologia , Proteínas de Insetos/metabolismo , Hidrolisados de Proteína/farmacologia , Selênio/farmacocinética , Tenebrio/metabolismo , Adulto , Aminoácidos/análise , Aminoácidos/metabolismo , Animais , Antioxidantes/metabolismo , Eritrócitos/efeitos dos fármacos , Hemólise/efeitos dos fármacos , Humanos , Hidrólise , Fatores Imunológicos/metabolismo , Proteínas de Insetos/farmacologia , Larva/efeitos dos fármacos , Larva/metabolismo , Camundongos , Hidrolisados de Proteína/metabolismo , Células RAW 264.7 , Selênio/análise , Subtilisinas/química , Subtilisinas/metabolismo , Tenebrio/efeitos dos fármacos
18.
Biosens Bioelectron ; : 112826, 2020 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-33262060

RESUMO

As one of the most common biological phenomena, cell adhesion plays a vital role in the cellular activities such as the growth and apoptosis, attracting tremendous research interests over the past decades. Taking the cell evolution under drug injection as an example, the dynamics of cell-substrate adhesion gap can provide valuable information in the fundamental research of cell contacts. A robust technique of monitoring the cell adhesion gap and its evolution in real time is highly desired. Herein, we develop a surface plasmon resonance holographic microscopy to achieve the novel functionality of real-time and wide-field mapping of the cell-substrate adhesion gap and its evolution in situ. The cell adhesion gap images of mouse osteoblast cells and human breast cancer cells have been effectively extracted in a dynamic and label-free manner. The proposed technique opens up a new avenue of revealing the cell-substrate interaction mechanism and renders the wide applications in the biosensing area.

19.
Nat Commun ; 11(1): 6160, 2020 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-33268791

RESUMO

Improving the accessibility of ions in the electrodes of electrochemical energy storage devices is vital for charge storage and rate performance. In particular, the kinetics of ion transport in organic electrolytes is slow, especially at low operating temperatures. Herein, we report a new type of MXene-carbon nanotube (CNT) composite electrode that maximizes ion accessibility resulting in exceptional rate performance at low temperatures. The improved ion transport at low temperatures is made possible by breaking the conventional horizontal alignment of the two-dimensional layers of the MXene Ti3C2 by using specially designed knotted CNTs. The large, knot-like structures in the knotted CNTs prevent the usual restacking of the Ti3C2 flakes and create fast ion transport pathways. The MXene-knotted CNT composite electrodes achieve high capacitance (up to 130 F g-1 (276 F cm-3)) in organic electrolytes with high capacitance retention over a wide scan rate range of 10 mV s-1 to 10 V s-1. This study is also the first report utilizing MXene-based supercapacitors at low temperatures (down to -60 °C).

20.
Langmuir ; 2020 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-33373522

RESUMO

Block copolymer microparticles with controllable morphology have drawn widespread attention owing to their promising applications in photonic materials, energy storage, and other areas. Hence, it is highly desired to achieve a controllable transformation of microparticle morphology. In this work, we report a simple method to shape the morphology of polystyrene-block-poly(dimethylsiloxane) (PS-b-PDMS) microparticles, by employing core-cross-linked polymeric nanoparticles (CNPs) as cosurfactants which are synthesized through cross-linking P4VP segment of PS-block-poly(4-vinylpyridine) (PS-b-P4VP). The addition of pH-responsive CNPs makes the shape of pH-inert PS-b-PDMS microparticles sensitive to pH value. The PS-b-PDMS microparticles transformed from elongated Janus pupa-like particles to onion-like particles by decreasing the pH value of the aqueous phase. The deformation mechanism is investigated by changing pH value, the weight fraction of CNPs, and surfactant property. This study provides a facile strategy to deform microparticles of pH-inert BCPs by tuning pH value, which is anticipated to be applicable to other non-pH-responsive BCP microparticles.

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