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1.
Mater Horiz ; 2021 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-34657943

RESUMO

Considering the operation reliability of flexible and optical electronics (FOEs) in dynamic and real-world environments, autonomous self-healing electromagnetic interference (EMI) shielding materials with high transparency, good stretchability and excellent tear-resistance are urgently required but always difficult to achieve due to the poor dynamics of their elastic substrates. Herein, we propose a facile strategy to design a highly dynamic polyurea elastomer (PDMS-MPI-HDI) featuring with ultrahigh optical transparency (>94%), ultralow elastic modulus (<1 MPa), high tear-resistant stretchability (800%), and ultrafast autonomous self-healing (100 s for scratch-healing). Taking PDMS-MPI-HDI as a substrate for embedding silver nanowires (Ag NWs), the first transparent, stretchable and self-healable EMI shielding materials (Ag NWs/PDMS-MPI-HDI) are presented. Failure behavior of Ag NWs/PDMS-MPI-HDI is highly tolerant of prefabricated cracks under deformation. Due to the robust interfacial adhesion between Ag NWs and PDMS-MPI-HDI, the fractured Ag NW network can autonomously self-reconstruct during the healing process of PDMS-MPI-HDI substrates, contributing to the complete restoration of EMI shielding effectiveness (SE) and full erasure of scratches at both the resting and stretching states. Besides, Ag NWs/PDMS-MPI-HDI exhibits fast autonomous self-healing at high (60 °C) and low (0 °C) temperatures, and in artificial sweat, which is essential for FOEs applicable in various practical environments.

2.
Hepatology ; 2021 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-34689362

RESUMO

BACKGROUND AND AIMS: Nonalcoholic fatty liver disease (NAFLD) is a progressive disease without known effective drug treatments. Switch-associated protein 70 (SWAP70) is a guanine nucleotide exchange factor that participates in the regulation of many cellular processes. However, the role of SWAP70 in NAFLD remains unclear. This study aimed to identify the function and mechanism of SWAP70 in NAFLD. APPROACH AND RESULTS: The results showed that the expression of SWAP70 was significantly increased in mice and hepatocytes after metabolic stimulation. Overexpression of SWAP70 in hepatocytes suppressed lipid deposition and inflammation, and SWAP70 knockdown created the inverse effect. Using hepatocyte-specific SWAP70 knockout and overexpression mice fed a high-fat, high-cholesterol diet, we demonstrated that SWAP70 suppressed the progression of nonalcoholic steatohepatitis by inhibiting lipid accumulation, inflammatory response and fibrosis. Mechanically, RNA-Seq analysis and immunoprecipitation assays revealed that SWAP70 inhibited the interaction between TAK1 binding protein 1 (TAB1) and transforming growth factor ß-activated kinase 1 (TAK1), sequentially suppressed the phosphorylation of TAK1 and subsequent c-Jun-N-terminal kinase (JNK)/P38 signaling. Inhibition of TAK1 activation blocked hepatocyte lipid deposition and inflammation caused by SWAP70 knockdown. CONCLUSIONS: SWAP70 is a protective molecule that can suppress the progression of NAFLD by inhibiting hepatic steatosis and inflammation. SWAP70 may be important for mitigating the progression of NAFLD.

3.
Hepatology ; 2021 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-34435375

RESUMO

BACKGROUND & AIMS: Although the prevalence of nonalcoholic fatty liver disease (NAFLD) has risen dramatically to 25% of the adult population worldwide, there are as yet no approved pharmacological interventions for the disease due to uncertainty about the underlying molecular mechanisms. It is known that mitochondrial dysfunction is an important factor in the development of NAFLD. Mitochondrial antiviral signaling protein (MAVS) is a critical signaling adaptor for host defenses against viral infection. However, the role of MAVS in mitochondrial metabolism during NAFLD progression remains largely unknown. APPROACH & RESULTS: Based on expression analysis, we identified a marked downregulation of MAVS in hepatocytes during NAFLD progression. By employing MAVS global knockout and hepatocyte-specific MAVS knockout mice, we found that MAVS is protective against diet-induced NAFLD. MAVS deficiency induces extensive mitochondrial dysfunction during NAFLD pathogenesis which was confirmed as impaired mitochondrial respiratory capacity and membrane potential. Metabolomics data also showed the extensive metabolic disorders after MAVS deletion. Mechanistically, MAVS interacts with the N-terminal stretch of voltage-dependent anion channel 2 (VDAC2), which is required for the ability of MAVS to influence mitochondrial function and hepatic steatosis. CONCLUSIONS: In hepatocytes, MAVS plays an important role in protecting against NAFLD by helping to regulate healthy mitochondrial function. These findings provide new insights regarding the metabolic importance of conventional immune regulators and support the possibility that targeting MAVS may represent a new avenue for treating NAFLD.

4.
Hepatology ; 74(4): 2133-2153, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34133792

RESUMO

BACKGROUND AND AIMS: Hepatic ischemia/reperfusion (I/R) injury, a common clinical problem that occurs during liver surgical procedures, causes a large proportion of early graft failure and organ rejection cases. The identification of key regulators of hepatic I/R injury may provide potential strategies to clinically improve the prognosis of liver surgery. Here, we aimed to identify the role of tumor necrosis factor alpha-induced protein 3-interacting protein 3 (TNIP3) in hepatic I/R injury and further reveal its immanent mechanisms. APPROACH AND RESULTS: In the present study, we found that hepatocyte TNIP3 was markedly up-regulated in livers of both persons and mice subjected to I/R surgery. Hepatocyte-specific Tnip3 overexpression effectively attenuated I/R-induced liver necrosis and inflammation, but improved cell proliferation in mice, whereas TNIP3 ablation largely aggravated liver injury. This inhibitory effect of TNIP3 on hepatic I/R injury was found to be dependent on significant activation of the Hippo-YAP signaling pathway. Mechanistically, TNIP3 was found to directly interact with large tumor suppressor 2 (LATS2) and promote neuronal precursor cell-expressed developmentally down-regulated 4-mediated LATS2 ubiquitination, leading to decreased Yes-associated protein (YAP) phosphorylation at serine 112 and the activated transcription of factors downstream of YAP. Notably, adeno-associated virus delivered TNIP3 expression in the liver substantially blocked I/R injury in mice. CONCLUSIONS: TNIP3 is a regulator of hepatic I/R injury that alleviates cell death and inflammation by assisting ubiquitination and degradation of LATS2 and the resultant YAP activation.TNIP3 represents a promising therapeutic target for hepatic I/R injury to improve the prognosis of liver surgery.

5.
Medicine (Baltimore) ; 100(12): e25250, 2021 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-33761722

RESUMO

BACKGROUND: Psoriasis vulgaris (PV) is an immune-mediated skin disease, which has seriously affected the quality of life of patients. At present, moxibustion therapy has been widely used in the treatment of PV. The purpose of this study is to provide high-quality evidence-based medicine to evaluate the effectiveness and safety of moxibustion for PV. METHODS: We will search the following Electronic databases from their inceptions to February 2021 without any language limitation: PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure, WangFang Database, Chinese Science Journal Database, Chinese Biomedical Literature Database. What's more, the grey literature and the references of all included literature will also be retrieved manually. Any clinical randomized controlled trials (RCTs) related to moxibustion therapy for PV will be taken into. In order to complete data synthesis and assess the risk of bias, we will use the RevMan V.5.3 software. RESULTS: This systematic review will provide an assessment of the current state of moxibustion for PV, aiming to assess the efficacy and safety of moxibustion for patients with PV. CONCLUSION: This systematic review will establish convincing evidence to prove the effectiveness and safety of moxibustion for PV. INPLASY REGISTRATION NUMBER: INPLASY202120008.


Assuntos
Moxibustão/métodos , Psoríase/terapia , Humanos , Metanálise como Assunto , Ensaios Clínicos Controlados Aleatórios como Assunto , Projetos de Pesquisa , Revisões Sistemáticas como Assunto , Resultado do Tratamento
6.
Angew Chem Int Ed Engl ; 60(14): 7947-7955, 2021 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-33432671

RESUMO

We designed and synthesized a colorless transparent glassy polyurethane assembled using low-molecular-weight oligomers carrying a large number of loosely packed weak hydrogen bonds (H-bonds), which has a glass transition temperature (Tg ) up to 36.8 °C and behaves unprecedentedly robust stiffness with a tensile Young's modulus of 1.56±0.03 GPa. Fast room-temperature self-healing was observed in this polymer network: the broken glassy polyurethane (GPU) specimen can recover to a tensile strength up 7.74±0.76 MPa after healing for as little as 10 min, which is prominent compared to reported room-temperature self-healing polymers. The high density of loose-packed hydrogen bonds can reversibly dissociate/associate below Tg of GPU (that is secondary relaxation), which enables the reconfiguration of the damaged network in the fractured interfaces, despite the extremely slow diffusion dynamics of molecular chains under room temperature. This GPU shows potential application as an optical lens.

8.
Cell Metab ; 31(5): 892-908.e11, 2020 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-32375062

RESUMO

Nonalcoholic steatohepatitis (NASH) is becoming one of the leading causes of hepatocellular carcinoma (HCC). Sorafenib is the only first-line therapy for advanced HCC despite its serious adverse effects. Here, we report that at an equivalent of approximately one-tenth the clinical dose for HCC, sorafenib treatment effectively prevents the progression of NASH in both mice and monkeys without any observed significant adverse events. Mechanistically, sorafenib's benefit in NASH is independent of its canonical kinase targets in HCC, but involves the induction of mild mitochondrial uncoupling and subsequent activation of AMP-activated protein kinase (AMPK). Collectively, our findings demonstrate a previously unappreciated therapeutic effect and signaling mechanism of low-dose sorafenib treatment in NASH. We envision that this new therapeutic strategy for NASH has the potential to translate into a beneficial anti-NASH therapy with fewer adverse events than is observed in the drug's current use in HCC.

9.
Mater Sci Eng C Mater Biol Appl ; 108: 110469, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31923958

RESUMO

The chemotherapy combined with gene therapy has emerged as a promising strategy for cancer therapy because of enhanced anticancer efficacy. To this end, we constructed a novel UV-light cross-linked and pH de-cross-linked coumarin-decorated cationic copolymer functionalized mesoporous silica nanoparticles (MSN) for co-delivery of chemotherapeutic agent 5-FU and tumor suppresser p53 gene. The multifunctional MSN were modified with poly(glycidyl methacrylate)-b-poly(2-(dimethylamino)ethyl methacrylate) (PGMA-b-PDMAEMA) via two sequential surface-initiated atom transfer radical polymerization (ATRP), followed by ring-opening of epoxy groups with ethanediamine and covalent conjugation with coumarin moieties via acid-liable cis-aconityl bonds. The in vitro drug release results indicated that the premature release was negligible at physiological pH when coumarin moieties on the MSN-g-PCAAMC-b-PDMAEMA surface underwent UV-light induced photo-dimerization (cross-linking), while the release of embedded drugs was accelerated under acidic conditions, which was attributed to the hydrolytic cleavage of cis-aconityl bonds (de-crosslinking). In addition to small-molecule drug, the established MSN-g-PCAAMC-b-PDMAEMA also could carry p53 gene in outer cationic copolymers, and the formed complex exhibited good gene transfection activity. Interestingly, coumarin moieties themselves could emit blue fluorescence, which was used to track the cellular uptake of the nanocarriers without the need of additional fluorescence probes. Importantly, the cytotoxicity and cell apoptosis assays confirmed that co-delivery of 5-FU and p53 gene by the cross-linked MSN-g-PCAAMC-b-PDMAEMA@5-FU/p53 induced enhanced chemotherapeutic efficacy as compared to 5-FU delivery alone. In conclusion, these results suggested that the constructed stimuli-responsive co-delivery system may hold the promise for cancer therapeutic application.


Assuntos
Cumarínicos/química , Reagentes para Ligações Cruzadas/química , Sistemas de Liberação de Medicamentos , Técnicas de Transferência de Genes , Nanopartículas/química , Polímeros/química , Dióxido de Silício/química , Animais , Materiais Biocompatíveis/química , Células COS , Cátions , Chlorocebus aethiops , Portadores de Fármacos , Fluoruracila/farmacologia , Hemólise , Humanos , Concentração de Íons de Hidrogênio , Hidrólise , Células MCF-7 , Plasmídeos/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Raios Ultravioleta
10.
Hepatology ; 71(1): 93-111, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31222801

RESUMO

Activation of apoptosis signal-regulating kinase 1 (ASK1) is a key driving force of the progression of nonalcoholic steatohepatitis (NASH) and represents an attractive therapeutic target for NASH treatment. However, the molecular and cellular mechanisms underlying ASK1 activation in the pathogenesis of NASH remain incompletely understood. In this study, our data unequivocally indicated that hyperactivated ASK1 in hepatocytes is a potent inducer of hepatic stellate cell (HSC) activation by promoting the production of hepatocyte-derived factors. Our previous serial studies have shown that the ubiquitination system plays a key role in regulating ASK1 activity during NASH progression. Here, we further demonstrated that tumor necrosis factor receptor-associated factor 6 (TRAF6) promotes lysine 6 (Lys6)-linked polyubiquitination and subsequent activation of ASK1 to trigger the release of robust proinflammatory and profibrotic factors in hepatocytes, which, in turn, drive HSC activation and hepatic fibrosis. Consistent with the in vitro findings, diet-induced liver inflammation and fibrosis were substantially attenuated in Traf6+/- mice, whereas hepatic TRAF6 overexpression exacerbated these abnormalities. Mechanistically, Lys6-linked ubiquitination of ASK1 by TRAF6 facilitates the dissociation of thioredoxin from ASK1 and N-terminal dimerization of ASK1, resulting in the boosted activation of ASK1-c-Jun N-terminal kinase 1/2 (JNK1/2)-mitogen-activated protein kinase 14(p38) signaling cascade in hepatocytes. Conclusion: These results suggest that Lys6-linked polyubiquitination of ASK1 by TRAF6 represents a mechanism underlying ASK1 activation in hepatocytes and a key driving force of proinflammatory and profibrogenic responses in NASH. Thus, inhibiting Lys6-linked polyubiquitination of ASK1 may serve as a potential therapeutic target for NASH treatment.


Assuntos
Apoptose , Hepatite/etiologia , Hepatócitos , Cirrose Hepática/etiologia , MAP Quinase Quinase Quinase 5/metabolismo , Fator 6 Associado a Receptor de TNF/fisiologia , Ubiquitinação , Animais , Lisina/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Índice de Gravidade de Doença
11.
J Colloid Interface Sci ; 560: 555-564, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31679783

RESUMO

Graphitic carbon nitride (g-C3N4) has aroused great concern since it applied to the photocatalytic process. However, the inherent shortcomings of bulk g-C3N4, such as small active surface area, low separation efficiency of photogenerated carriers, sluggish charge transport process, etc., result in low-level photocatalytic performance. The rich-nitrogen carbon nitride nanotubes (CNNTs) made by an easy supermolecule self-assembly method could slove these subsisting problems. The CNNTs with unique morphology possess superior separation/migration of photo-excited charge carriers and enhanced photocatalytic performance. Under irradiation with visible light (λ > 400 nm), measured with Pt (3 wt%) as co-catalyst, the CNNTs have a hydrogen evolution rate of 18.06 mmol h-1 g-1 and its apparent quantum yield (AQY) is 12.55% (420 nm). The CNNTs are also applied to degrade antibiotics with simultaneous hydrogen production, providing a method for alleviating energy crisis and environmental pollution issues. The degradation rate of bisphenol A (BPA) is 92% and simultaneously with 13.63 µmol photocatalytic hydrogen generation after irradiation for 5 h.

12.
ACS Appl Mater Interfaces ; 11(4): 4425-4438, 2019 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-30608123

RESUMO

Novel acid/alkali/corrosion potential triple-stimuli-responsive smart nanocontainers (TSR-SNs) were successfully assembled to regulate the release of an encapsulated corrosion inhibitor, benzotriazole (BTA), by installing specially structured bistable pseudorotaxanes as supramolecular nanovalves onto orifices of mesoporous silica nanoparticles. In normal conditions, BTA molecules were sealed in the mesopores. Upon any stimulus of acid, alkali, or corrosion potential, BTA molecules were quickly released because of the open states of the supramolecular nanovalves. TSR-SNs as smart nanocontainers were added into the SiO2-ZrO2 sol-gel coating to fabricate a stimuli-feedback, corrosion-compensating self-healing anticorrosion coating (SF-SHAC). Compared with the conventional pH-responsive smart nanocontainers synthesized for the SHAC, TSR-SNs not only respond to the pH changes occurring on corrosive microregions but also, and more importantly, feel the corrosion potential of aluminum alloys and give quick feedback. This design avoids wasting smart nanocontainers because of the local-dependent, gradient pH stimulus intensities and obviously enhances the response sensitivity of the SF-SHAC. Electrochemical impedance spectroscopy and salt spray tests prove the excellent physical barrier of the SF-SHAC. Through scanning vibrating electrode technique measurements, the SF-SHAC doped with TSR-SNs demonstrates inhibiting rates for corrosive microcathodic/anodic current densities that are faster than other control SHACs. The new incorporated corrosion potential-responsive function ensures the efficient working efficiency of TSR-SNs and makes full use of the preloaded corrosion inhibitors as repair factors.

13.
ACS Biomater Sci Eng ; 5(11): 6022-6035, 2019 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-33405724

RESUMO

Integrating multimodality bioimaging and multiple stimuli-responsive controlled drug release properties into one single nanosystem for therapeutic application is highly desirable but still remains a challenge. Herein, we coated a hollow mesoporous silica shell on to upconversion nanoparticles (UCNPs) and conjugated pillarene-based supramolecular valves on to surface of UCNPs@hm-SiO2 using amine-coumarin phototriggers to obtain the multifunctional nanoparticles, UCNPs@hm-SiO2-Cou-Cys-DOX/WP[5]. Benefiting from the core-shell structured UCNPs, the UCNPs@hm-SiO2-Cou-Cys-DOX/WP[5] can serve as efficient contrast agents for upconversion luminescence and T1-weighted magnetic resonance imaging in vitro/in vivo. More importantly, depending on exquisitely designed supramolecular valves, UCNPs@hm-SiO2-Cou-Cys-DOX/WP[5] can realize zero-premature release under normal physiological conditions (pH 7.4), which produces minimal damage to normal tissue, whereas this nanosystem can respond to several disease-related signals, including acid (most cancers), alkali (metabolic alkalosis), and Zn2+ (Alzheimer's disease), along with two external stimuli, including near-infrared (NIR) light and reductive electrical potential, via altering the spatial structure of pseudorotaxanes, disassembling the molecular stalks, or undergoing photochemical reactions, ultimately resulting in opening of the gatekeepers and release of encapsulated drugs. The multifunctional UCNP-based nanoparticles were endowed with such quintuple stimuli-responsive controlled release characteristics. Specifically, in anticancer application, the rational utilization of the two of them, acid and NIR light, could regulate the release amount and rate of DOX from UCNPs@hm-SiO2-Cou-Cys-DOX/WP[5], accelerate the accumulation of DOX in cell nuclei, and thereby promote the cancer cell apoptosis, indicating that the nanomaterials have promising application in cancer treatment. This study provides a novel design strategy for constructing multifunctional UCNP-based nanoparticles with multiple stimuli-responsive drug release features, which have great potential in diagnosis and therapy of relevant diseases as theranostic nanomedicines.

14.
Nat Commun ; 9(1): 4311, 2018 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-30333484

RESUMO

How neurons are capable of decoding stimulus intensity and translate this information into complex behavioral outputs is poorly defined. Here, we demonstrate that the C. elegans interneuron AIB regulates two types of behaviors: reversal initiation and feeding suppression in response to different concentrations of quinine. Low concentrations of quinine are decoded in AIB by a low-threshold, fast-inactivation glutamate receptor GLR-1 and translated into reversal initiation. In contrast, high concentrations of quinine are decoded by a high-threshold, slow-inactivation glutamate receptor GLR-5 in AIB. After activation, GLR-5 evokes sustained Ca2+ release from the inositol 1,4,5-trisphosphate (IP3)-sensitive Ca2+ stores and triggers neuropeptide secretion, which in turn activates the downstream neuron RIM and inhibits feeding. Our results reveal that distinct signal patterns in a single interneuron AIB can encode differential behavioral outputs depending on the stimulus intensity, thus highlighting the importance of functional mapping of information propagation at the single-neuron level during connectome construction.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/fisiologia , Comportamento Alimentar/fisiologia , Interneurônios/fisiologia , Receptores de AMPA/metabolismo , Animais , Sinalização do Cálcio , Proteínas de Transporte/metabolismo , Quinina , Células Receptoras Sensoriais/fisiologia , Limiar Sensorial
15.
Biophys Rep ; 4(1): 17-24, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29577066

RESUMO

Feeding behavior is the most fundamental behavior in C. elegans. Our previous results have dissected the central integration circuit for the regulation of feeding, which integrates opposing sensory inputs and regulates feeding behavior in a nonlinear manner. However, the peripheral integration that acts downstream of the central integration circuit to modulate feeding remains largely unknown. Here, we find that a Gαi/o-coupled tyramine receptor, TYRA-2, is involved in peripheral feeding suppression. TYRA-2 suppresses feeding behavior via the AIM interneurons, which receive tyramine/octopamine signals from RIM/RIC neurons in the central integration circuit. Our results reveal previously unidentified roles for the receptor TYRA-2 and the AIM interneurons in feeding regulation, providing a further understanding of how biogenic amines tyramine and octopamine regulate feeding behavior.

16.
Chemistry ; 23(60): 15041-15045, 2017 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-28940669

RESUMO

Novel quadruple stimuli-responsive mechanized silica nanoparticles were constructed by installation of supramolecular nanovalves onto the exterior surface of mesoporous silica nanoparticles. The release of cargo molecules is triggered by acid/Zn2+ /alkali/reduction potential stimuli. This has potential application in the development of drug delivery systems or construction of smart anticorrosion coatings.

17.
ACS Appl Mater Interfaces ; 9(24): 21034-21047, 2017 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-28545298

RESUMO

Corrosion potential stimulus-responsive smart nanocontainers (CP-SNCs) are designed and synthesized based on the installation of the supramolecular assemblies (bipyridinium ⊂ water-soluble pillar[5]arenes) onto the exterior surface of magnetic nanovehicles (Fe3O4@mSiO2), linked by disulfide linkers. The supramolecular assemblies with high binding affinity as gatekeepers effectively block the encapsulated organic corrosion inhibitor, 8-hydroxyquinoline (8-HQ), within the mesopores of Fe3O4@mSiO2. When the corrosion potential of the magnesium alloy (-1.5 V vs SHE) is exerted, 8-HQ is released instantly because of the cleavage of disulfide linkers and the removal of the supramolecular assemblies. CP-SNCs were incorporated into the hybrid organic-inorganic sol-gel coating to construct a corrosion potential stimulus-feedback anticorrosion coating (CP-SFAC) that was then deposited on the magnesium alloy, AZ31B. With the aid of a magnetic field, CP-SNCs were gathered in the proximity of the surface of AZ31B. CP-SFAC showed a satisfactory anticorrosion performance, more importantly, through the evaluation of microzone electrochemical techniques. CP-SFAC presented the rapid self-healing functionality when the localized corrosion occurred. Shortening the distance between CP-SNCs and the surface of AZ31B enhances the availability of the incorporated CP-SNCs and makes most of the CP-SNCs to timely respond to the corrosion potential stimulus and facilitates the formation of a compact molecular protective film before the corrosion products pile up. The characteristics of fast response time and quick self-healing rate meet the requirements of the magnesium alloy for self-healing in local regions.

18.
J Hazard Mater ; 332: 195-204, 2017 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-28324713

RESUMO

As an emerging carbonaceous material, carbon aerogels (CAs) display a great potential in environmental cleanup. In this study, a macroscopic three-dimensional monolithic cobalt-doped carbon aerogel was developed by co-condensation of graphene oxide sheets and resorcinol-formaldehyde resin in the presence of cobalt ions, followed by lyophilization, carbonization and thermal treatment in air. Cobalt ions were introduced as a polymerization catalyst to bridge the organogel framework, and finally cobalt species were retained as both metallic cobalt and Co3O4, wrapped by graphitized carbon layers. The material obtained after a thermal treatment in air (CoCA-A) possesses larger BET specific surface area and pore volume, better hydrophilicity and lower leaching of cobalt ions than that without the post-treatment (CoCA). Despite of a lower loading of cobalt content and a larger mass transfer resistance than traditional powder catalysts, CoCA-A can efficiently eliminate organic contaminants by activation of peroxymonosulfate with a low activation energy. CoCA-A can float beneath the surface of aqueous solution and can be taken out completely without any changes in morphology. The monolith is promising to be developed into an alternative water purification technology due to the easily separable feature.

19.
Molecules ; 21(12)2016 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-27999414

RESUMO

Benefiting from the development of nanotechnology, drug delivery systems (DDSs) with stimuli-responsive controlled release function show great potential in clinical anti-tumor applications. By using a DDS, the harsh side effects of traditional anti-cancer drug treatments and damage to normal tissues and organs can be avoided to the greatest extent. An ideal DDS must firstly meet bio-safety standards and secondarily the efficiency-related demands of a large drug payload and controlled release function. This review highlights recent research progress on DDSs with stimuli-responsive characteristics. The first section briefly reviews the nanoscale scaffolds of DDSs, including mesoporous nanoparticles, polymers, metal-organic frameworks (MOFs), quantum dots (QDs) and carbon nanotubes (CNTs). The second section presents the main types of stimuli-responsive mechanisms and classifies these into two categories: intrinsic (pH, redox state, biomolecules) and extrinsic (temperature, light irradiation, magnetic field and ultrasound) ones. Clinical applications of DDS, future challenges and perspectives are also mentioned.


Assuntos
Antineoplásicos/química , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos , Humanos , Concentração de Íons de Hidrogênio , Luz , Campos Magnéticos , Nanopartículas/química , Nanotecnologia , Nanotubos de Carbono/química , Neoplasias/tratamento farmacológico , Oxirredução , Polímeros/química , Pontos Quânticos/química , Temperatura , Ultrassom
20.
ACS Appl Mater Interfaces ; 8(35): 23289-301, 2016 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-27523904

RESUMO

We demonstrate for the first time how to assemble mechanized hollow zirconia nanospheres (MHzNs), consisting of hollow mesoporous zirconia nanospheres (HMZNs) as nanoscaffolds and supramolecular switches anchored on the exterior surface of HMZNs. The remarkable advantage of substitution of HMZNs for conventional mesoporous silica nanoscaffolds is that HMZNs can suffer the hot alkaline reaction environment, which provides a novel strategy for functionalization and thus achieve dual pH-mediated controlled release functions by simple and practicable assembly procedure. Under neutral solution, cucurbituril[7] (CB[7]) macrocycles complexed with propanone bis(2-aminoethyl)ketal (PBAEK) to form [2]pseudorotaxanes as supramolecular switches, blocking the pore orifices and preventing the undesirable leakage of cargoes. When solution pH was adjusted to alkaline range, CB[7] macrocycles, acting as caps, disassociated from PBAEK stalks and opened the switches due to the dramatic decrease of ion-dipole interactions. While under acidic conditions, PBAEK stalks were broken on account of the cleavage of ketal groups, resulting in the collapse of supramolecular switches and subsequent release of encapsulated cargoes. MHzNs owning dual pH-mediated controlled release characteristic are expected to apply in many fields. In this work, the feasibility of doxorubicin (DOX)-loaded MHzNs as targeted drug delivery systems was evaluated. In vitro cellular studies demonstrate that DOX-loaded MHzNs can be easily taken up by SMMC-7721 cells, can rapidly release DOX intracellularly, and can enhance cytotoxicity against tumor cells, proving their potential for chemotherapy.

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