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1.
BMC Pediatr ; 24(1): 359, 2024 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-38783220

RESUMO

BACKGROUND: Hypoxemia represents the most prevalent adverse event during flexible bronchoscopy procedures aimed at foreign body retrieval in pediatric patients; if not expeditiously managed, it carries the potential for cardiac or respiratory arrest. The specific risk factors contributing to the occurrence of hypoxemia during foreign body FB removal via bronchoscopy have yet to be definitively established. METHODS: This retrospective study included a cohort of 266 pediatric subjects from January 1, 2015, to December 31, 2022, who underwent flexible bronchoscopy for the purpose of FB extraction. In this cohort, the supraglottic airway was used to connect the anesthesia apparatus during the removal procedure. RESULTS: In total, 45 of the pediatric patients (16.9%) experienced episodes of hypoxemia during the FB removal procedure. Multivariate analysis revealed that the following factors were significantly associated with the occurrence of hypoxemia: an operation time exceeding 60 min (odds ratio [OR] 8.55; 95% confidence interval [CI] 3.82-19.13), a maximum diameter exceeding 7 mm (OR 5.03; 95% CI, 2.24-11.29), and the presence of radiological evidence indicating pneumonia (OR 2.69; 95% CI, 1.27-5.69). CONCLUSION: During flexible bronchoscopy procedures aimed at FB removal in pediatric patients, there is an increased susceptibility to hypoxemia. Factors including extended operation duration, larger FB dimensions, and radiographic evidence suggestive of pneumonia significantly contribute to a heightened risk of hypoxemia.


Assuntos
Broncoscopia , Corpos Estranhos , Hipóxia , Humanos , Broncoscopia/efeitos adversos , Estudos Retrospectivos , Corpos Estranhos/complicações , Feminino , Masculino , Hipóxia/etiologia , Criança , Pré-Escolar , Fatores de Risco , Lactente , Duração da Cirurgia , Adolescente
2.
Macromol Rapid Commun ; 45(2): e2300482, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37922939

RESUMO

Living crystallization-driven self-assembly (CDSA) has emerged as an efficient route to generate π-conjugated-polymer-based nanofibers (CPNFs) with promising applications from photocatalysis to biomedicine. However, the lack of efficient tools to endow CPNFs with morphological stability and surface tailorability becomes a frustrating hindrance for expanding application spectrum of CPNFs. Herein, a facile strategy to fabricate length-controllable OPV-based (OPV = oligo(p-phenylenevinylene)) CPNFs containing a cross-linked shell with high morphological stability and facile surface tailorability through the combination of living CDSA and thiol-ene chemistry by using OPV5 -b-PNAAM32 (PNAAM = poly(N-allyl acrylamide)) as a model is reported. Uniform fiber-like micelles with tunable length can be generated by self-seeding of living CDSA. By taking advantage of radical thiol-ene reaction between vinyls of PNAAM corona and four-arm thiols, the shell of micelles can be cross-linked with negligible destruction of structure of vinylene-containing OPV core. The resulting micelles show high morphological stability in NaCl solution and PBS buffer, even upon heating at 80 °C. The introduced extra thiol groups in the cross-linked shell can be further employed to install extra functional moieties via convenient thiol-Michael-type reaction. Given the negligible cytotoxicity of resulting CPNFs, this strategy opens an avenue to fabricate various CPNFs of diverse functionalities for biomedicine.


Assuntos
Micelas , Nanofibras , Polímeros/química , Cristalização , Compostos de Sulfidrila/química
3.
Fundam Res ; 3(1): 93-101, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38933561

RESUMO

Fragmentation/disassembly of fiber-like micelles generated by living crystalline-driven self-assembly (CDSA) is usually encountered in aqueous media, which hinders the applications of micelles. Herein, we report the generation of uniform fiber-like micelles consisting of a π-conjugated oligo(p-phenylenevinylene) core and a cross-linking silica shell with grafted poly(ethylene glycol) (PEG) chains by the combination of living CDSA, silica chemistry and surface grafting-onto strategy. Owing to the presence of crosslinking silica shell and the outmost PEG chains, the resulting micelles exhibit excellent dispersity and colloidal stability in PBS buffer, BSA aqueous solution and upon heating at 80 °C for 2 h without micellar fragmentation/disassembly. The micelles also show negligible cytotoxicity toward both HeLa cervical cancer and HEK239T human embryonic kidney cell lines. Interestingly, micelles with L n of 156 nm show the "stealth" property with no significant uptake by HeLa cells, whereas some certain amounts of micelles with L n of 535 nm can penetrate into HeLa cells, showing length-dependent cellular uptake behaviors. These results provide a route to prepare uniform, colloidally stable fiber-like nanostructures with tunable length and functions derived for biomedical applications.

4.
BMC Anesthesiol ; 22(1): 357, 2022 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-36418946

RESUMO

BACKGROUND: To evaluate the safety and effectiveness of different dosages of intranasal Dexmedetomidine (DEX) in combination with oral midazolam for sedation of young children during brain MRI examination. METHODS: Included in this prospective single-blind randomized controlled trial were 156 children aged from 3 months to 6 years and weighing from 4 to 20 Kg with ASA I-II who underwent brain MRI examination between March 2021 and February 2022. Using the random number table method, they were divided into group A (using 3 ug/kg intranasal DEX plus 0.2 mg/Kg oral midazolam) and group B (using 2 ug/kg intranasal DEX plus 0.2 mg/Kg oral Midazolam). The one-time success rate of sedation, sedation onset time, recovery time, overall sedation time, and occurrence of adverse reactions during MRI examination were compared between the two groups. The heart rate (HR), mean arterial pressure (MAP), and percutaneous SpO2before and after drug administration were observed in both groups. Differences in sedation scores between the two groups were compared before intranasal drug administration (T0), 10 min after drug administration (T1), at the time of falling asleep (T2), at the end of examination (T3), and at the time of recovery (T4). RESULTS: The one-time success rate of sedation in group A and B was 88.31% and 79.75% respectively, showing no significant difference between the two groups (P>0.05). The sedation onset time in group A was 24.97±16.94 min versus 27.92±15.83 min in group B, and the recovery time was 61.88±22.18 min versus 61.16±28.16 min, both showing no significance difference between the two groups (P>0.05). Children in both groups exhibited good drug tolerance without presenting nausea and vomiting, hypoxia, or bradycardia and hypotension that needed clinical interventions. There was no significant difference in the occurrence of abnormal HR, MAP or other adverse reactions between the two groups (P>0.05). CONCLUSION: 3 ug/kg or 2 ug/kg intranasal DEX in combination with 0.2 mg/kg oral Midazolam both are safe and effective for sedation of children undergoing MRI examination with the advantages of fast-acting and easy application. TRIAL REGISTRATION: It was registered at the Chinese Clinical Trial Registry ( ChiCTR1800015038 ) on 02/03/2018.


Assuntos
Dexmedetomidina , Midazolam , Criança , Humanos , Pré-Escolar , Administração Intranasal , Dexmedetomidina/efeitos adversos , Hipnóticos e Sedativos , Método Simples-Cego , Estudos Prospectivos , Imageamento por Ressonância Magnética , Encéfalo/diagnóstico por imagem
5.
BMC Anesthesiol ; 22(1): 219, 2022 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-35831787

RESUMO

BACKGROUND: Reintubation is a severe complication during foreign body (FB) removal that uses flexible bronchoscopy. OBJECTIVE: To investigate the incidence and risk factors for reintubations in children undergoing FB extraction by flexible bronchoscopy in a single center. DESIGN: A retrospective cross-sectional study. SETTING: All children with foreign body aspiration at Fujian Maternity and Child Health Hospital, Affiliated Hospital of Fujian Medical University from January 2015 to December 2020. PATIENTS: Children with FB removal using a flexible bronchoscopy were enrolled in the trial according to the inclusion criteria. MEASUREMENTS: Both multivariable and logistic regression analyses were used to analyze the association between characteristic data and reintubations. The results were presented as odds ratios (ORs) with 95% confidence intervals (CIs). RESULTS: In total, 244 patients met with the inclusion criteria and were included in the analysis. Among those participants, 28 children (11.5%) underwent reintubations after FB removal by flexible bronchoscopy. Independent factors associated with reintubations were identified as operative time ≥ 60 min [OR: 3.68, 95% CI (1.64-8.82)] and ASA ≥ III [OR: 5.7, 95% CI (1.23-26.4)]. CONCLUSIONS: Children undergoing FB removal by a flexible bronchoscopy may encounter with a high incidence of postoperative reintubations. Both long operative duration and a severe physical status cause a growing risk of reintubations.


Assuntos
Broncoscopia , Corpos Estranhos , Broncoscopia/métodos , Criança , Estudos Transversais , Feminino , Corpos Estranhos/epidemiologia , Corpos Estranhos/cirurgia , Humanos , Incidência , Lactente , Gravidez , Estudos Retrospectivos , Fatores de Risco
6.
BMC Anesthesiol ; 21(1): 299, 2021 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-34852767

RESUMO

BACKGROUND: Propofol, a widely used sedative in endoscopic procedures, sometimes causes cardiopulmonary complications. Intravenous lidocaine can diminish visceral pain and decrease the dose of propofol. The purpose of this study was to assess the efficacy and safety of intravenous lidocaine in reducing propofol dosage during paediatric colonoscopy. METHODS: Forty children who underwent colonoscopy were divided into two groups. Lidocaine hydrochloride (1.5 mg/kg induction and 2 mg/kg/h maintenance) was given intravenously to the lidocaine group, and the same amount of saline was given to the control group after they received lidocaine induction. Propofol initial plasma concentration of 5 µg/mL was targeted, and the procedure was performed after the bispectral index value reached 55. The primary outcome was propofol requirement. RESULTS: The propofol requirement in the lidocaine group was decreased by 35.5% (128.6 ± 30.4 mg vs. 199.4 ± 57.6 mg; p < 0.001; 95%CI: - 100.60, - 41.02). The incidence of involuntary body movements was significantly lower in the lidocaine group (p = 0.028; OR = 0.17; 95%CI: 0.03, 0.92). The awakening time (p < 0.001; 95%CI: - 7.67, - 5.13) and recovery times (p < 0.001; 95%CI: - 7.45, - 4.35) were significantly lower in the lidocaine group. Pain was significantly less at 30 min and 60 min after the procedure in the lidocaine group (0 [0-4] vs. 3 [0-5], p < 0. 001; 0 [0-2] vs. 1 [0-3], p = 0.001). There was no difference in the incidence of bradycardia, hypotension, or hypoxia between the two groups. CONCLUSIONS: For colonoscopy procedures in paediatric patients, intravenous lidocaine reduces the amount of propofol needed, provides better sedation and postprocedural pain management, as well as a reduction in recovery time. TRIAL REGISTRATION: The trial was registered on November 6, 2020 at China Clinical Trials Registration Center ( www.chictr.org.cn ) ref.: ChiCTR 2,000,039,706.


Assuntos
Anestésicos Intravenosos/administração & dosagem , Anestésicos Locais/farmacologia , Colonoscopia/métodos , Lidocaína/farmacologia , Propofol/administração & dosagem , Anestésicos Locais/administração & dosagem , Criança , Pré-Escolar , Relação Dose-Resposta a Droga , Método Duplo-Cego , Feminino , Humanos , Lidocaína/administração & dosagem , Masculino
7.
Chem Commun (Camb) ; 57(98): 13259-13274, 2021 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-34816824

RESUMO

π-Conjugated-polymer-based nanofibers (CPNFs) of controlled length, composition and morphology are promising for a broad range of emerging applications in optoelectronics, biomedicine and catalysis, owing to the morphological merits of fiber-like nanostructures and structural attributes of π-conjugated polymers. Living crystallization-driven self-assembly (CDSA) of π-conjugated-polymer-containing block copolymers (BCPs) has emerged as an efficient strategy to prepare CPNFs with precise dimensional and structural controllability by taking advantage of the crystallinity of π-conjugated polymers. In this review, recent advances in the generation of CPNFs have been highlighted. The influence of the structure of π-conjugated-polymer-containing BCPs and experimental conditions on the CDSA behaviors, especially seeded growth and self-seeding processes of living CDSA, has been discussed in detail, aiming to provide an in-depth overview of living CDSA of π-conjugated-polymer-containing BCPs. In addition, the properties of CPNFs as well as their potential applications have been illustrated. Finally, we put forward the current challenges and research directions in the field of CPNFs.

8.
Chemistry ; 27(33): 8479-8483, 2021 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-33834551

RESUMO

In this work, it is demonstrated for the first time that heterojunction nanowires, consisting of a gradient and segmented-like heterogeneous π-conjugated core with controllable length, composition and morphology, can be generated by co-self-seeding of oligo(p-phenylene vinylene) (OPV)- and oligo(p-phenylene ethynylene) (OPE)-containing block copolymers in spite of different chain lengths and molecular conformation for OPE and OPV. More importantly, based on the understanding of the formation of heterogeneous core by the co-self-seeding approach, a "heating/cooling" seeded growth route was developed, by which linear and branched heterojunction nanowires containing a segmented heterogeneous π-conjugated core of controlled length, composition and morphology can be obtained. This work provides a versatile platform to generate heterojunction nanowires with excellent controllability in length, composition, and morphology.

9.
Chem Rec ; 20(10): 1198-1219, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32881320

RESUMO

As the world moves toward electromobility, our daily lives are flooded with variety of lithium ion batteries (LIBs), and the concerns of cost, safety and environmental friendliness of LIBs spring up in the minds of scientists. Although organic electrodes have been considered as promising alternatives to their inorganic counterparts, some intrinsic weaknesses still plague scientists, such as high solubility, low conductivity and sluggish ion diffusion. The emergence of covalent organic frameworks (COFs) attracts our attention because of their robust networks and open pores that could facilitate the infiltration of electrolyte ions when used as electrodes for metal-ion batteries (MIBs). In this review, we summarized the recent progress of COFs as electrode materials, and the strategies toward enhancing electrochemical performance of COF-based electrode in MIBs are discussed. Hopefully, this review will provide a fundamental guidance for future development of COF-based electrodes.

10.
Biomater Sci ; 8(21): 6037-6044, 2020 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-32996946

RESUMO

Hydrogen peroxide (H2O2) is an important mediator in biological medicine, disease diagnosis and environmental analyses and therefore it is essential to develop a detection approach for H2O2 in physical environments. Herein, we designed and prepared a series of AuNP-containing nanocomposites (AuNPs@NGO-PEG, AuNPs@G1-PAMAM-NGO-PEG and AuNPs@G3-PAMAM-NGO-PEG) for enhanced non-enzymatic H2O2 detection. We firstly demonstrated functionalized nanographene oxide (NGO) based materials, which combined advantages of biocompatible poly(ethylene glycol) (PEG), hyperbranched polyamidamine (PAMAM) dendrimer and thiol active site, as compatible platforms. Gold nanoparticles (AuNPs) were then aptly in situ grown on these functionalized NGO based materials via the reduction of HAuCl4 under mild conditions, i.e. AuNPs@NGO-PEG, AuNPs@G1-PAMAM-NGO-PEG and AuNPs@G3-PAMAM-NGO-PEG nanocomposites, which possess stable and uniform AuNPs standing on the functionalized NGO sheets. For H2O2 detection, these nanocomposites were cast on a glassy carbon electrode (GCE) conveniently, i.e. GCE/AuNPs@NGO-PEG, GCE/AuNPs@G1-PAMAM-NGO-PEG and GCE/AuNPs@G3-PAMAM-NGO-PEG. It is evident that these GCEs could be applied as efficient non-enzymatic H2O2 detectors resulting from the corresponding cyclic voltammetric curves and typical ready-state amperometric curves. GCE/AuNPs@G1-PAMAM-NGO-PEG exhibited the fastest electron transfer rate among these modified GCEs. We envisage that these GCEs could provide efficient sensors for H2O2 detection and a new strategy for sensor design.


Assuntos
Grafite , Nanopartículas Metálicas , Nanocompostos , Técnicas Eletroquímicas , Ouro , Peróxido de Hidrogênio , Óxidos , Polietilenoglicóis
11.
Biomed Res Int ; 2020: 1587214, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32685442

RESUMO

BACKGROUND: Sevoflurane is commonly used as a general anesthetic in neonates to aged patients. Preconditioning or postconditioning with sevoflurane protects neurons from excitotoxic injury. Conversely, sevoflurane exposure induces neurotoxicity during early or late life. However, little is known about the underlying mechanism of the dual effect of sevoflurane on neurons. Autophagy is believed to control neuronal homeostasis. We hypothesized that autophagy determined the dual effect of sevoflurane on neurons. METHODS: DTome was used to identify the direct protein target (DPT) of sevoflurane. The STRING database was employed to investigate the proteins associated with the DPTs. Protein-protein interaction was assessed using Cytoscape. WebGestalt was used to analyze gene set enrichment. The linkage between candidate genes and autophagy was identified using GeneCards. RESULTS: This study found that 23 essential DPTs of sevoflurane interacted with 77 proteins from the STRING database. GABARAPL1 and 2, both of which are DPT- and autophagy-associated proteins, were significantly expressed in the brain and enriched in GABAergic synapses. CONCLUSIONS: Taken together, our findings showed that the network of sevoflurane-DPT-GABARAPL1 and 2 is related to the dual effect of sevoflurane on neurons.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Família da Proteína 8 Relacionada à Autofagia/metabolismo , Autofagia/efeitos dos fármacos , Bases de Dados de Ácidos Nucleicos , Proteínas Associadas aos Microtúbulos/metabolismo , Neurônios/metabolismo , Mapas de Interação de Proteínas/efeitos dos fármacos , Sevoflurano/farmacologia , Proteínas Adaptadoras de Transdução de Sinal/genética , Família da Proteína 8 Relacionada à Autofagia/genética , Humanos , Proteínas Associadas aos Microtúbulos/genética
12.
Biomater Sci ; 8(8): 2300-2307, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32176228

RESUMO

Stimuli-responsive polymer nano-capsules toward a specific signaling molecule show great potential in the fabrication of smart and efficient controlled/targeted drug vehicles. Herein, we design and synthesize a PEG45-b-PVPOP14 diblock copolymer (PEG = poly(ethylene glycol) and PVPOP = poly(4-vinylphenyl 4-oxopentanoate), the subscripts representing the number of repeat units of each block) with levulinate-protected phenol side groups. The PEG45-b-PVPOP14 diblock copolymer could self-assemble to form large compound micelles in aqueous media. Since the core of the large compound micelles formed contains both hydrophilic PEG and hydrophobic PVPOP domains, this kind of micelle is able to load both hydrophobic and hydrophilic species within the core. The ester moiety of levulinate-protected phenol can be selectively cleaved upon incubation with a sulfite, a derivative of SO2 in aqueous media, to give phenol groups. Thus, the sulfite exhibits the ability to alter the amphiphilicity and further the self-assembled behavior of PEG45-b-PVPOP14. The release of payloads in the core of micelles can be accelerated by triggering of the sulfite. Significantly, the nano-capsule of PEG45-b-PVPOP14 shows specific response to the sulfite (SO2) with slight interference of other bio-species, such as Cys, GSH and Hcy. As far as we are aware, this is the first example of a nano-capsule with sulfite (SO2) specific responsiveness. We envisage that this polymer model could broaden the scope of biological signaling molecule responsive macromolecular systems and provide a new platform to fabricate SO2-responsive biomedicine materials.


Assuntos
Micelas , Nanopartículas/química , Polímeros/química , Dióxido de Enxofre/química , Liberação Controlada de Fármacos , Irinotecano/química , Ácidos Levulínicos/química , Transdução de Sinais , Inibidores da Topoisomerase I/química
13.
BMC Pregnancy Childbirth ; 20(1): 151, 2020 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-32164593

RESUMO

BACKGROUND: Intravenous remifentanil patient-controlled analgesia (RPCA) is an alternative for epidural analgesia (EA) in labor pain relief. However, it remains unknown whether RPCA is superior to EA in decreasing the risk of intrapartum maternal fever during labor. METHODS: According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a systematic review and meta-analysis was performed by searching PubMed, EMBASE and the Cochrane Central Register of Controlled Trials from inception to April 2019. All randomized controlled trials (RCTs) investigating the risk of intrapartum maternal fever with RPCA compared with EA alone or EA in combination with spinal analgesia during labor were included. RESULTS: A total of 825 studies were screened, and 6 RCTs including 3341 patients were identified. Compared with EA, RPCA was associated with a significantly lower incidence of intrapartum maternal fever (risk ratio [RR] 0.48, P = 0.02, I2 = 49%) during labor analgesia. After excluding 2 trials via the heterogeneity analysis, there was no difference in the incidence of intrapartum fever between patients receiving RPCA and those receiving EA. Satisfaction with pain relief during labor was lower in the RPCA group than that in the EA group (- 10.6 [13.87, - 7.44], P < 0.00001, I2 = 0%). The incidence of respiratory depression was significantly greater in the RPCA group than that in the EA group (risk ratio 2.86 [1.65, 4.96], P = 0.0002, I2 = 58%). The incidence of Apgar scores < 7 at 5 min in the RPCA group was equivalent to that in the EA group. CONCLUSION: There is no solid evidence to illustrate that the incidence of intrapartum maternal fever is lower in patients receiving intravenous RPCA than in patients receiving EA.


Assuntos
Analgesia Epidural/métodos , Analgesia Controlada pelo Paciente/métodos , Analgésicos Opioides/uso terapêutico , Dor do Parto/tratamento farmacológico , Remifentanil/uso terapêutico , Analgesia Obstétrica/métodos , Índice de Apgar , Feminino , Febre/terapia , Humanos , Recém-Nascido , Trabalho de Parto , Complicações do Trabalho de Parto/terapia , Manejo da Dor/métodos , Medição da Dor , Satisfação do Paciente , Gravidez
14.
Angew Chem Int Ed Engl ; 59(21): 8232-8239, 2020 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-32022396

RESUMO

Fiber-like π-conjugated nanostructures are important components of flexible organic electronic and optoelectronic devices. To broaden the range of potential applications, one needs to control not only the length of these nanostructures, but the introduction of diverse functionality with spatially selective control. Here we report the synthesis of a crystalline-coil block copolymer of oligo(p-phenylenevinylene)-b-poly(2-vinylpyridine) (OPV5 -b-P2VP44 ), in which the basicity and coordinating/chelating ability of the P2VP segment provide a landscape for the incorporation of a variety of functional inorganic NPs. Through a self-seeding strategy, we were able to prepare monodisperse fiber-like micelles of OPV5 -b-P2VP44 with lengths ranging from 50 to 800 nm. Significantly, the exposed two ends of OPV core of these fiber-like micelles remained active toward further epitaxial deposition of OPV5 -b-PNIPAM49 and OPV5 -b-P2VP44 to generate uniform A-B-A and B-A-B-A-B segmented block comicelles with tunable lengths for each block. The P2VP domains in these (co-)micelles can be selectively decorated with inorganic and polymeric nanoparticles as well as metal oxide coatings, to afford hybrid fiber-like nanostructures. This work provides a versatile strategy toward the fabrication of narrow length dispersity continuous and segmented π-conjugated OPV-containing fiber-like micelles with the capacity to be decorated in a spatially selective way with varying functionalities.

15.
ACS Appl Mater Interfaces ; 12(1): 1588-1596, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31840506

RESUMO

Antifouling surfaces with optimized conformation and compositional heterogeneities are presented with the goal of improving the efficacy of surface protection. The approach exploits the adhesive group (thiol or catechol chain end) to anchor asymmetric polymer brushes (APBs) bearing amphiphilic side chains with synergistic nonfouling and fouling-release abilities onto the surface. The conformation of the APB surface is close to the fencelike structure, which mimics lubricating protein lubricin, endowing the surface with capacity of enhanced protection and antiadhesivity, even facing the high compression of fouling. By utilizing a poly(Br-acrylate-alkyne) macroagent comprising alkynyl and 2-bromopropionate groups, we prepared a series of APB surfaces based on polyacrylate-g-poly(ethylene oxide)/poly(pentafluorophenyl methacrylate) (PA-g-PEO/PPFMA) APBs to explore the influence of the content of the fluorinated segment and bioinspired topological polymer chemistry on their antifouling performance. The APB surfaces can not only provide compositional heterogeneities of PEO and fluorinated segments in each side chain but also give a high surface coverage because of the characteristic of high grafting density of macromolecular brushes. It was found for the first time, as far as we are aware, the fencelike APB surface shows excellent antifouling performance with less protein adsorption (up to 91% off) and cell adhesion (up to 84% off) in comparison with the controlled substrate under relatively long incubation time.


Assuntos
Adesivos/farmacologia , Biomimética , Adesão Celular/efeitos dos fármacos , Propriedades de Superfície/efeitos dos fármacos , Adesivos/química , Adsorção/efeitos dos fármacos , Alcinos/química , Catecóis/química , Catecóis/farmacologia , Metacrilatos/química , Metacrilatos/farmacologia , Conformação Molecular , Polietilenoglicóis/química , Polietilenoglicóis/farmacologia , Polímeros/química , Polímeros/farmacologia , Compostos de Sulfidrila/química , Compostos de Sulfidrila/farmacologia
16.
J Colloid Interface Sci ; 560: 50-58, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31639564

RESUMO

HYPOTHESIS: Crystallization-driven self-assembly (CDSA) of block copolymers (BCPs) with a crystallizable core-forming oligo(p-phenylenevinylene) (OPV) segment can be a powerful strategy for the preparation of uniform fiber-like nanostructures containing a π-conjugated core with controlled dimension and composition. However, the self-assembly landscape can be complex, and our understanding of the nucleation and growth processes in the CDSA of BCPs with a crystalline π-conjugated segment is limited. EXPERIMENTS: We used fluorescence spectroscopy and 1H NMR to follow the self-assembly of oligo(p-phenylenevinylene)-b-poly(N-isopropyl acrylamide) (OPV5-b-PNIPAM49), a typical π-conjugated-coil BCP, as solution of the BCP in ethanol is cooled from 80 °C to 23 °C and allowed to age, µDSC to monitor the crystallization exotherm, and DLS and TEM to follow micelle growth. We see a striking difference in the experiments that monitor unimer in solution comparing to those that monitor micelle growth. We see nearly complete disappearance of unimer within 30 min upon cooling. In contrast, the micelles continue to grow, increasing in length by a factor of ten over the next several hours. We are able to exclude growth by end-to-end coupling. FINDINGS: We propose a self-assembly mechanism in which short semi-crystalline rod-like micelles form upon cooling, accompanied by small amorphous aggregates. Unimers that dissociate from these aggregates subsequently deposit on the growing ends of the core-crystalline micelles. We also find that the length of the PNIPAM block affects the elongation kinetics of OPV5-b-PNIPAM.

17.
Biomed Pharmacother ; 118: 109334, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31545269

RESUMO

Long noncoding RNAs (lncRNAs) have been implicated in neurogenesis. LncRNA WNT5A-AS is upregulated in neural stem cells (NSCs), the proliferation of which is inhibited by sevoflurane. Thus, we hypothesized that knocking down of lncRNA WNT5A-AS may restore the fate of NSCs exposed to sevoflurane. To test this hypothesis, NSCs obtained from postnatal Sprague-Dawley rats were exposed to 2.4% sevoflurane or control gas for 6 h. Bioinformatics analysis, quantitative PCR and RNA interference technology were used to identify the properties of lncRNA WNT5A-AS. Cell proliferation was assessed using counting a Cell Counting Kit-cell 8 assay, a 5-ethynyl-2'-deoxyuridine incorporation assay, and a plate cloning assay. Cell survival was detected by flow cytometry, which was also used to examine the levels of reactive oxygen species (ROS) and the cell cycle. The levels of WNT5A and receptor tyrosine kinase (Ryk) were measured via Western blotting. LncRNA WNT5A-AS was identified to have low coding potency and to be located on the antisense strand of WNT5A. The level of upregulated lncRNA WNT5A-AS was positively correlated with that of WNT5A in response to sevoflurane exposure. The knockdown of lncRNA WNT5A-AS promoted the proliferation and survival of NSCs, whereas it suppressed the WNT5A/Ryk-ROS signaling and drove cell cycle processes. Taken together, findings strongly suggest that the inhibition of lncRNA WNT5A-AS can rescue the fate of NSCs. In addition, WNT5A/Ryk-ROS signaling might be a downstream target of lncRNA WNT5A-AS.


Assuntos
Linhagem da Célula , Células-Tronco Neurais/citologia , Células-Tronco Neurais/metabolismo , RNA Longo não Codificante/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Receptores Proteína Tirosina Quinases/metabolismo , Sevoflurano/farmacologia , Proteína Wnt-5a/metabolismo , Animais , Sequência de Bases , Ciclo Celular/efeitos dos fármacos , Linhagem da Célula/efeitos dos fármacos , Linhagem da Célula/genética , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Células-Tronco Neurais/efeitos dos fármacos , RNA Longo não Codificante/genética , Ratos Sprague-Dawley
18.
Nanoscale ; 11(12): 5330-5335, 2019 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-30843565

RESUMO

Covalent organic frameworks (COFs) have attracted increasing interest for their use as electrode materials for lithium-ion batteries (LIBs) by virtue of their microporous crystalline structures and robust networks. However, the tightly stacked bulk COFs and their intrinsic low conductivity inevitably result in an inefficient utilization of redox-active sites so as to lower the electrochemical performance. Herein, we proposed a general strategy to improve the energy storage capability of polyimide (PI)-COF based cathode materials, which included the decrease of their stacked layer numbers to a few layers via a mechanical milling method for the efficient utilization of redox-active sites and the incorporation of few-layer COF sheets with chemically reduced graphene oxide (rGO) to increase the charge transfer. The excellent electrochemical performance of the composite few-layer PI-COFs with rGO cathodes indicated that reducing the layer number of COFs and incorporating rGO may pave the way for the successful development of COF-based organic electrodes for LIBs.

19.
Nanomaterials (Basel) ; 9(2)2019 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-30823551

RESUMO

A facile strategy to prepare GO-based nanocomposites with both gold nanoparticles (AuNPs) and ferrocene (Fc) moieties was developed. The surface of GO was modified with PFcMAss homopolymer by surface-initiated atom transfer radical polymerization of a new methacrylate monomer of 2-((2-(methacryloyloxy)ethyl)disulfanyl)ethyl ferrocene-carboxylate (FcMAss), consisting of disulfide as an anchoring group for stabilizing AuNPs and Fc group as an additional functionality. AuNPs with an average diameter of about 4.1 nm were formed in situ on the surface of PFcMAss-decorated GO (GO-PFcMAss) via Brust-Schiffrin method to give GO-PFcMAss-AuNPs multifunctional nanocomposites bearing GO, AuNPs and Fc groups. The obtained nanocomposites were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscopy (TEM) and atomic force microscopy (AFM). Since disulfide-containing polymers, rather than the commonly used thiol-containing compounds, were employed as ligands to stabilize AuNPs, much more stabilizing groups were attached onto the surface of GO, and thus more AuNPs were able to be introduced onto the surface of GO. Besides, polymeric chains on the surface of GO endowed GO-PFcMAss-AuNPs nanocomposites with excellent colloidal stability, and the usage of a disulfide group provides possibility to efficiently incorporate additional functionalities by easily modifying structure of disulfide-based monomer.

20.
Nanomaterials (Basel) ; 9(2)2019 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-30764568

RESUMO

An efficient strategy for growing thermo-sensitive polymers from the surface of exfoliated graphene oxide (GO) is reported in this article. GO sheets with hydroxyls and epoxy groups on the surface were first prepared by modified Hummer's method. Epoxy groups on GO sheets can be easily modified through ring-opening reactions, involving nucleophilic attack by tris(hydroxymethyl) aminomethane (TRIS). The resulting GO-TRIS sheets became a more versatile precursor for next ring opening polymerization (ROP) of ethyl ethylene phosphate (EEP), leading to GO-TRIS/poly(ethyl ethylene phosphate) (GO-TRIS-PEEP) nanocomposite. The nanocomposite was characterized by ¹H NMR, Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), differential thermal gravity (DTG), transmission electron microscopy (TEM) and atomic force microscopy (AFM). Since hydrophilic PEEP chains make the composite separate into single layers through hydrogen bonding interaction, the dispersity of the functionalized GO sheets in water is significantly improved. Meanwhile, the aqueous dispersion of GO-TRIS-PEEP nanocomposite shows reversible temperature switching self-assembly and disassembly behavior. Such a smart graphene oxide-based hybrid material is promising for applications in the biomedical field.

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