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1.
Semin Thromb Hemost ; 49(7): 673-678, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36108652

RESUMO

BACKGROUND: Left ventricular thrombus (LVT) is a common complication of dilated cardiomyopathy (DCM), causing morbidity and mortality. METHODS: This study retrospectively analyzed patients with DCM from January 2002 to August 2020 in Beijing Anzhen Hospital. Clinical characteristics were compared between the LVT group and the age and sex 1:4 matched with the LVT absent group. The receiver operator characteristic (ROC) curve was plotted to evaluate the diagnostic value of D-dimer predicting LVT occurrence in DCM. RESULTS: A total of 3,134 patients were screened, and LVT was detected in 72 (2.3%) patients on echocardiography. The patients with LVT had higher D-dimer, fibrinogen, and lower systolic blood pressure than those without LVT. The ejection fraction (EF) was lower and left ventricular end-systolic diameter was larger in the LVT group. Severe mitral regurgitation (MR) was more common in the LVT absent groups. The prevalence of atrial fibrillation was lower in the LVT group. The ROC curve analysis yielded an optimal cut-off value of 444 ng/mL DDU (D-dimer units) for D-dimer to predict the presence of LVT. Multivariable binary logistic regression analysis revealed that EF (OR = 0.90, 95% CI = 0.86-0.95), severe MR (OR = 0.19, 95% CI = 0.08-0.48), and D-dimer level (OR = 15.4, 95% CI = 7.58-31.4) were independently associated with LVT formation. CONCLUSION: This study suggested that elevated D-dimer levels (>444 ng/mL DDU) and reduced EF were independently associated with increased risk of LVT formation. Severe MR could decrease the incidence of LVT.


Assuntos
Cardiomiopatia Dilatada , Trombose , Humanos , Estudos Retrospectivos , Cardiomiopatia Dilatada/complicações , Fatores de Risco
2.
Sensors (Basel) ; 23(13)2023 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-37447979

RESUMO

In this study, a range of miniaturized Ag/AgCl reference electrodes with various layouts were successfully fabricated on wafer-level silicon-based substrates with metallic intermediate layers by precisely controlling the electrochemical deposition of Ag, followed by electrochemical chlorination of the deposited Ag layer. The structure, as well as the chemical composition of the electrode, were characterized with SEM & EDS. The results showed that the chlorination is very sensitive to the applied electric field and background solution. Potentiostatic chlorination, in combination with an adjusted mushroom-shaped Ag sealing deposition, enabled the formation of electrochemical usable Ag/AgCl layers. The stability of the electrodes was tested using open circuit potential (OCP) measurement. The results showed that the reference electrodes stayed stable for 300 s under 3 M KCl solution. The first stage study showed that the stability of the Ag/AgCl reference electrode in a chip highly depends on chip size design, chlorination conditions, and a further protection layer.


Assuntos
Compostos de Prata , Prata , Prata/química , Compostos de Prata/química , Eletrodos , Microeletrodos
3.
Zhongguo Zhen Jiu ; 44(7): 851-5, 2024 Jul 12.
Artigo em Zh | MEDLINE | ID: mdl-38986600

RESUMO

The theory of Huatuo Jiaji (EX-B 2) is the representative of the knowledge construction of ancient anatomy, reflecting the academic thought of Huatuo's school. Through deeply analyzing the classic theory of acupuncture and its cultural and historical materials, it is believed that the five-body constituents are the structural basis of Huatuo Jiaji (EX-B 2), qi and blood are the material one, while biaoben (the sites where meridian qi gathers and diffuses) and qijie (the common pathways through which meridian qi gathers) indicate its functions. Huatuo Jiaji (EX-B 2) reveals the rules of the transverse distribution of meridian points and the relevant indications, providing the theoretic foundation for acupuncture treatment. It highlights the importance of the anatomical knowledge in acupuncture effect and proposes a new idea for establishing an effective classification system of meridian points.


Assuntos
Pontos de Acupuntura , Terapia por Acupuntura , Medicina na Literatura , Meridianos , Humanos , História Antiga , Terapia por Acupuntura/história , China , Acupuntura/história , Acupuntura/educação
4.
Acupunct Med ; 41(5): 307-316, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37166069

RESUMO

OBJECTIVE: The hypothalamic paraventricular nucleus (PVN) acts as a critical integrating center of endocrine/autonomic responses and regulates visceral functional activities. However, its involvement in electroacupuncture (EA) treatment of chronic glomerulonephritis (CGN) remains unclear. METHODS: Over four experiments, we randomized 111 rats into: control, untreated model (CGN) or EA-treated model (CGN + EA) groups, a model group receiving EA after PVN damage (CGN + EA + Lesion) or untreated model groups injected with adeno-associated viral vectors encoding human M4 muscarinic receptor (CGN + hM4D) or enhanced green fluorescent protein (CGN + EGFP). CGN was modeled by intraperitoneal injection of bovine serum albumin for 2 weeks. Rats in the CGN + EA and CGN + EA + Lesion groups received EA at bilateral ST36 and KI3 for 14 days. Urine/serum samples were collected to evaluate inflammatory factors and changes in renal function. RESULTS: EA inhibited the release of interleukin (IL)-6, tumor necrosis factor (TNF)-α and IL-1ß, and decreased urine protein (PRO), creatinine (Cre) and blood urea nitrogen (BUN) levels. PVN damage influenced the effect of EA on the levels of these parameters. EA appeared to inhibit the firing frequency and spectral energy of PVN neurons. In the viral vector experiment, levels of PRO, Cre, IL-6, IL-1ß and TNF-α in the CGN group were increased in CGN versus control groups (p < 0.0001), decreased in CGN + hM4D versus CGN groups (p < 0.05) and did not differ between CGN + EGFP and control groups (p > 0.05). CONCLUSION: Our findings indicate that EA at ST36 and KI3 improves CGN in this rat model by weakening the activity of PVN neurons, alleviating impairment of renal function impairment and restricting the release of inflammatory factors.


Assuntos
Eletroacupuntura , Glomerulonefrite , Humanos , Ratos , Animais , Núcleo Hipotalâmico Paraventricular/metabolismo , Doença Crônica , Fator de Necrose Tumoral alfa/metabolismo , Glomerulonefrite/metabolismo , Interleucina-6/metabolismo
5.
Exp Ther Med ; 25(4): 166, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36936708

RESUMO

The optimum dose of isoprenaline (ISO) required to induce stress cardiomyopathy (SC) in mice is not known. The present study aimed to investigate the dose-response association and determine the optimum dose of ISO to establish a high-morbidity/low-mortality SC mouse model to simulate the clinical symptoms of SC. A total of 72 6-week-old wild-type female mice (C57BL/6) were randomly divided into control mice administered normal saline and mice treated with increasing ISO concentrations (5, 10, 25, 50 and 100 mg/kg ISO intraperitoneal injections daily for 14 consecutive days). All mice were analysed by body weight assessment, open field test (OFT), echocardiography (Echo), electrocardiogram (ECG), assessment of myocardial pathology and quantification of cortisol, brain natriuretic peptide (BNP), cardiac troponin T (cTnT), catecholamine (CA) and C-reactive protein (CRP). Compared with the control group, the 25 and 50 mg/kg ISO groups exhibited the most prominent weight changes and lower mortality. The open-field test showed a significant decrease in autonomous activity behaviour in the 25 and 50 mg/kg ISO groups compared with the control group (P<0.05). Echo revealed that the apex of the heart was balloon-like in the 25 and 50 mg/kg ISO groups, along with prominent left ventricular dyskinesia. ECG showed a significant increase in ST segment amplitude, QT interval and Q amplitude (P<0.05) in the 25 and 50 mg/kg ISO group compared with the control group. Haematoxylin and eosin staining of heart tissue showed a disordered arrangement of myocardial cells, dissolution of myocardial fibres and cytoplasm, notable widening of myocardial cell space, oedema and hyperaemia of the interstitium, whereas heart tissue of the control group was structurally intact. Compared with the control group, the 25 and 50 mg/kg ISO groups exhibited significantly higher levels of cortisol, BNP, cTNT, CA and CRP (P<0.05). A high-incidence low-mortality SC model was successfully and stably developed by administration of 25 and 50 mg/kg ISO. Such models may provide a basis for the development of other animal models of SC.

6.
Zhongguo Zhen Jiu ; 43(8): 959-62, 2023 Aug 12.
Artigo em Zh | MEDLINE | ID: mdl-37577896

RESUMO

The paper summarizes the definition, location and main indication of qicimai points recorded in Huangdi Neijing (Yellow Emperor 's Inner Classic). It is found that qicimai points are the "upward moving points" in reference to the meridian distribution rule of "rooting, running, infusing and moving"; and corresponding to the sites of "running outwards and inwards" of the meridians' "separating, meeting and running outwards and inwards". It also includes the infusing points for the sea of qi and marrow. The new idea, "selecting qicimai points for the treatment of qi obstruction in the neck gate", is proposed. Based on the systematic application of the acupoints on the nape region, it is anticipated that a new approach will be provided to the treatment of the diseases in the neck, shoulder, head, face, the five sensory organs, mental disorders and zangfu qi dysfunction.


Assuntos
Terapia por Acupuntura , Meridianos , Humanos , Pontos de Acupuntura
7.
ACS Omega ; 8(6): 5702-5714, 2023 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-36816681

RESUMO

In this study, synthetic pure cassiterite and cassiterite doped with two different Fe contents were successfully recrystallized by means of sintering. Their crystal structure and chemical compositions were characterized by X-ray powder diffraction (XRD) as well as scanning electron microscopy (SEM) combined with energy-dispersive X-ray (EDX) analysis. Their floatability was studied by microflotation with a diphosphonic acid surfactant named Lauraphos301 as a collector. Unlike the addition of ferric ions in solution, which strongly depressed the floatability of all of the cassiterite samples, a much higher flotation efficiency of the Fe-doped cassiterite samples was found especially at lower collector concentrations. The cassiterite floatability is proportional to the Fe content in cassiterite at a broad range of pH, and the recovery has the following order: cassiterite with 1417 ppm Fe > cassiterite with 1165 ppm Fe > pure cassiterite. The electrokinetic behavior of the cassiterite samples with and without the collector was studied by electrophoretic measurements and revealed that the chemical interaction dominated the adsorption. With the help of the particle shape analysis, a more angular shape was found for the Fe-doped cassiterite samples. Moreover, without the influence of particle shape, much abundant adsorption of Lauraphos301 was found on the Fe-doped cassiterite samples by AFM topography imaging. The minor amount of Fe in the cassiterite lattice and a more angular shape of the Fe-doped cassiterite samples were believed to enhance floatability collectively. The study reveals that the influence of the chemical composition of the minerals on flotation was almost inextricably bound up with particle morphology and emphasizes the importance of considering both factors and investigating them individually for the flotation study.

8.
Zhongguo Zhen Jiu ; 43(4): 379-89, 2023 Apr 12.
Artigo em Zh | MEDLINE | ID: mdl-37068812

RESUMO

OBJECTIVE: To observe the effects of electroacupuncture (EA) on cardiac function and local field potential (LFP) in sensory and motor cortices in mice with stress cardiomyopathy (SC), and to explore the possible mechanism of EA in improving SC. METHODS: Twenty-seven female C57BL/6 mice were randomized into a blank group, a model group and an EA group, 9 mice in each group. In the model group and the EA group, SC model was established by continuous intraperitoneal injection of isoproterenol (ISO) for 14 days. At the same time of modeling, EA was applied at "Neiguan" (PC 6) and "Shenmen" (HT 7) in the EA group, with disperse-dense wave, in frequency of 2 Hz/15 Hz, 15 min each time, once a day for 14 days. After intervention, the total movement distance, the number of crossing grid and the number of crossing central grid of open field test within 5 minutes were observed; the left ventricular function indexes (left ventricular diameter of end-diastole [LVIDd], left ventricular diameter of end-systole [LVIDs], left ventricular volume of end-diastole [LVEDV], left ventricular volume of end-systole [LVESV], ejection fraction [EF] and fraction shortening [FS]) were detected by echocardiography; the changes in ST-segment amplitude and PR interval of electrocardiogram were observed; the morphology of myocardial tissue was observed by HE staining; the serum levels of cortisol (CORT), cardiac troponin T (cTnT) and brain natriuretic peptide (BNP) were detected by ELISA; the changes of LFP in sensory and motor cortices were recorded by Plexon multi-channel acquisition system. RESULTS: Compared with the blank group, in the model group, the total movement distance, the number of crossing grid and the number of crossing central grid of open field test were decreased (P<0.05); LVIDd, LVIDs, LVEDV and LVESV were increased (P<0.05), EF and FS were decreased (P<0.05); ST-segment amplitude was increased (P<0.05) and PR interval was prolonged (P<0.05); irregular myocardial fiber arrangement, interstitial edema and inflammatory cell infiltration were observed; the serum levels of CORT, cTnT and BNP were increased (P<0.05); in the sensory cortex, the ratios of delta, theta, alpha and beta frequency bands were increased (P<0.05), the maximum energy spectrum of theta and beta frequency bands was increased (P<0.05), the power spectral density (PSD) of delta, theta, alpha, beta and gamma frequency bands was increased (P<0.05); in the motor cortex, the ratios of delta, theta, alpha and beta frequency bands were increased (P<0.05), the maximum energy spectrum as well as PSD of delta, theta, alpha, beta and gamma frequency bands were increased (P<0.05). Compared with model group, in the EA group, the total movement distance, the number of crossing grid and the number of crossing central grid of open field test were increased (P<0.05); LVIDd, LVIDs, LVEDV and LVESV were decreased (P<0.05), EF and FS were increased (P<0.05); ST-segment amplitude was decreased (P<0.05), and the PR interval was shortened (P<0.05); myocardial fiber injury and inflammatory cell infiltration were reduced; the serum levels of CORT, cTnT and BNP were decreased (P<0.05); in the sensory cortex, the ratios of theta, alpha and beta frequency bands were decreased (P<0.05), the ratio of gamma frequency band was increased (P<0.05), the maximum energy spectrum of theta frequency band as well as the PSD of theta, alpha, beta and gamma frequency bands were decreased (P<0.05); in the motor cortex, the ratios of theta, alpha and beta frequency bands were decreased (P<0.05) and the ratio of gamma frequency band was increased (P<0.05), the maximum energy spectrum of delta frequency band was increased (P<0.05), the maximum energy spectrum of theta frequency band as well as the PSD of theta and gamma frequency bands were decreased (P<0.05). CONCLUSION: EA can improve cardiac function in mice with stress cardiomyopathy, and its mechanism may be related to the regulation of local field potentials in sensory and motor cortices.


Assuntos
Eletroacupuntura , Córtex Motor , Cardiomiopatia de Takotsubo , Feminino , Camundongos , Animais , Camundongos Endogâmicos C57BL , Miocárdio
9.
Zhongguo Zhen Jiu ; 42(11): 1269-77, 2022 Nov 12.
Artigo em Zh | MEDLINE | ID: mdl-36397225

RESUMO

OBJECTIVE: To observe the effect of electroacupuncture (EA) on vascular endothelial growth factor-C (VEGF-C), vascular endothelial growth factor receptor-3 (VEGFR-3), proinflammatory factors and apoptosis in myocardial tissue in mice with acute myocardial ischemia (AMI), and to explore the mechanism of EA for AMI. METHODS: Fifty male C57BL/6 mice were randomly divided into a sham operation group, a model group, an EA group, an inhibitor group and an inhibitor+EA group, 10 mice in each group. Except for the sham operation group, the mice in the remaining groups were intervented with ligation at the left anterior descending (LAD) coronary artery to establish AMI model. The mice in the sham operation group were intervented without ligation after thoracotomy. The mice in the EA group were intervented with EA at "Shenmen" (HT 7) and "Tongli" (HT 5), disperse-dense wave, 2 Hz/15 Hz in frequency, 1 mA in current intensity, 30 min each time, once a day, for 3 d. The mice in the inhibitor group were treated with intraperitoneal injection of SAR 131675 (12.5 mg•kg-1•d-1, once a day for 3 d). The mice in the inhibitor+EA group were injected intraperitoneally with SAR 131675 30 min before EA. The ECG before modeling, 30 min after modeling and 3 d after intervention was detected, and the ST segment displacement was recorded; after the intervention, the ELISA method was applied to measure the contents of serum creatine kinase isoenzyme (CK-MB), aspartate aminotransferase (AST) as well as tumor necrosis factor-α (TNF-α) and interleukin-23 (IL-23) in myocardial tissue; the HE staining method was used to observe the morphological changes of myocardial tissue; the immunofluorescence double labeling method was applied to measure the number of co-expression positive cells of VEGF-C/VEGFR-3 in myocardial tissue; the TUNEL method was used to detect the level of cardiomyocyte apoptosis; the Western blot method was applied to measure the protein expressions of VEGF-C, VEGFR-3, b-lymphoma-2 (Bcl-2), activated caspase-3 (Cleaved Caspase-3) and activated poly adenosine diphosphate ribose polymerase-1 (Cleaved PARP-1). RESULTS: Compared with the sham operation group, in the model group the ST segment displacement was increased (P<0.01); the contents of CK-MB, AST, TNF-α and IL-23 were increased (P<0.01); the arrangement of myocardial fibers was disordered, and interstitial inflammatory cell infiltration was obvious; the number of co-expression positive cells of VEGF-C/VEGFR-3 was decreased (P<0.01); the number of cardiomyocyte apoptosis was increased (P<0.01); the expressions of VEGF-C, VEGFR-3 and Bcl-2 were decreased (P<0.01); the expressions of Cleaved Caspase-3 and Cleaved PARP-1 were increased (P<0.01). Compared with the model group, in the EA group the ST segment displacement was decreased (P<0.01); the contents of CK-MB, AST, TNF-α, IL-23 were decreased (P<0.01); the severity of myocardial pathological injury was reduced; the number of co-expression positive cells of VEGF-C/VEGFR-3 was increased (P<0.01); the number of cardiomyocyte apoptosis was reduced (P<0.01); the expressions of VEGF-C, VEGFR-3 and Bcl-2 were increased (P<0.01); the expressions of Cleaved Caspase-3 and Cleaved PARP-1 were reduced (P<0.01). There was no significant difference in all the indexes between the model group and the inhibitor group (P>0.05). Compared with the model group, the protein expression of VEGF-C was increased in the inhibitor+EA group (P<0.01). Compared with the inhibitor group, in the EA group the ST segment displacement was decreased (P<0.01); the contents of CK-MB, AST, TNF-α, IL-23 were decreased (P<0.01); the severity of myocardial pathological injury was reduced; the number of co-expression positive cells of VEGF-C/VEGFR-3 was increased (P<0.05); the number of cardiomyocyte apoptosis was reduced (P<0.01); the expressions of VEGF-C, VEGFR-3 and Bcl-2 were increased (P<0.01); the expressions of Cleaved Caspase-3 and Cleaved PARP-1 were reduced (P<0.01). Compared with the inhibitor+EA group, all the indexes in the EA group were improved except the protein expression of VEGF-C (P<0.01). CONCLUSION: EA could relieve the inflammatory reaction and apoptosis in AMI mice, and its mechanism may be related to activating VEGF-C/VEGFR-3 pathway and promoting lymphangion genesis.


Assuntos
Eletroacupuntura , Isquemia Miocárdica , Camundongos , Masculino , Animais , Receptor 3 de Fatores de Crescimento do Endotélio Vascular , Caspase 3 , Fator C de Crescimento do Endotélio Vascular , Fator de Necrose Tumoral alfa/genética , Fator A de Crescimento do Endotélio Vascular/genética , Inibidores de Poli(ADP-Ribose) Polimerases , Camundongos Endogâmicos C57BL , Isquemia Miocárdica/genética , Isquemia Miocárdica/terapia , Isquemia Miocárdica/metabolismo , Apoptose , Interleucina-23 , Proteínas Proto-Oncogênicas c-bcl-2
10.
ACS Omega ; 6(6): 4212-4226, 2021 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-33644544

RESUMO

In this study, the physicochemical behaviors of the (110), (100), as well as (001) of SnO2 were investigated by using high-resolution direct force spectroscopy. The measurements were conducted between a silica sphere and sample surfaces in 10 mmol/L KCl between pH 3.1 and 6.2 using colloidal probe atomic force microscopy (cp-AFM-hydrophilic). Dissimilar interactions were detected on different-oriented surfaces. The pH values where the force switched from positive to negative can be clearly distinguished and be ordered as SnO2(100) < SnO2(001) ≈ SnO2(110). By fitting the force curves in the Derjaguin-Landau-Verwey-Overbeck theory framework, anisotropic surface potentials were computed between the three sample surfaces following a similar trend as force interaction. To study the implication of crystallographic orientation to surfactant adsorption, we used Aerosol 22 (sulfosuccinamate) as an anionic collector for cassiterite flotation to functionalize the different samples at pH 3. The contact angle measurements, the topography visualizations by AFM, and the force measurement using cp-AFM with hydrophobized spheres (cp-AFM-hydrophobized) have shown that Aerosol 22 was adsorbed on the sample surfaces inhomogeneously. The adsorption followed the range of SnO2(110) > SnO2(100) > SnO2(001) in the concentration from 1 × 10-6 to 1 × 10-4 mol/L.

11.
Clin Cardiol ; 44(10): 1422-1431, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34318505

RESUMO

BACKGROUND: Atrial fibrillation (AF) and stable coronary artery disease (SCAD) frequently coexist. HYPOTHESIS: To investigate the prognosis of catheter ablation versus drug therapy in patients with AF and SCAD. METHODS: In total, 25 512 patients with AF in the Chinese AF Registry between 2011 and 2019 were screened for SCAD. 815 patients with AF and SCAD underwent catheter ablation therapy were matched with patients by drug therapy in a 1:1 ratio. Primary end point was composite of thromboembolism, coronary events, major bleeding, and all-cause death. The secondary endpoints were each component of the primary endpoint and AF recurrence. RESULTS: Over a median follow-up of 45 ± 23 months, the patients in the catheter ablation group had a higher AF recurrence-free rate (53.50% vs. 18.41%, p < .01). In multivariate analysis, there was no significant difference between the strategy of catheter ablation and drug therapy in primary composite end point (adjusted HR 074, 95%CI 0.54-1.002, p = .0519). However, catheter ablation was associated with fewer all-cause death independently (adjusted HR 0.36, 95%CI 0.22-0.59, p < .01). In subgroup analysis, catheter ablation was an independent risk factor for all-cause death in the high-stroke risk group (adjusted HR 0.39, 95%CI 0.23-0.64, p < .01), not in the low-medium risk group (adjusted HR 0.17, 95%CI 0.01-2.04, p = .17). CONCLUSIONS: In the patients with AF and SCAD, catheter ablation was not independently associated with the primary composite endpoint compared with drug therapy. However, catheter ablation was an independent protective factor of all-cause death.


Assuntos
Fibrilação Atrial , Ablação por Cateter , Doença da Artéria Coronariana , Antiarrítmicos/uso terapêutico , Fibrilação Atrial/complicações , Fibrilação Atrial/diagnóstico , Fibrilação Atrial/terapia , Estudos de Coortes , Doença da Artéria Coronariana/complicações , Doença da Artéria Coronariana/diagnóstico , Doença da Artéria Coronariana/cirurgia , Humanos , Prognóstico , Estudos Prospectivos , Recidiva , Fatores de Risco , Resultado do Tratamento
13.
ACS Nano ; 10(6): 5991-8, 2016 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-27175931

RESUMO

A strategy for creating elastomeric conducting polyaniline networks is described. Simultaneous elastomeric mechanical properties (E < 10 MPa) and electronic conductivities (σ > 10 S cm(-1)) are achieved via molecular templating of conjugated polymer networks. Diblock copolymers with star topologies processed into self-assembled elastomeric thin films reduce the percolation threshold of polyaniline synthesized via in situ polymerization. Block copolymer templates with star topologies produce elastomeric conjugated polymer composites with Young's moduli ranging from 4 to 12 MPa, maximum elongations up to 90 ± 10%, and electrical conductivities of 30 ± 10 S cm(-1). Templated polyaniline films exhibit Young's moduli up to 3 orders of magnitude smaller compared to bulk polyaniline films while preserving comparable bulk electronic conductivity. Flexible conducting polymers have prospective applications in devices for energy storage and conversion, consumer electronics, and bioelectronics.


Assuntos
Compostos de Anilina , Polímeros , Nanoestruturas , Estudos Prospectivos
14.
Biomaterials ; 39: 164-72, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25468368

RESUMO

Mammalian cells detect and respond to topographical cues presented in natural and synthetic biomaterials both in vivo and in vitro. Micro- and nano-structures influence the adhesion, morphology, proliferation, migration, and differentiation of many phenotypes. Although the mechanisms that underpin cell-topography interactions remain elusive, synthetic substrates with well-defined micro- and nano-structures are important tools to elucidate the origin of these responses. Substrates with reconfigurable topography are desirable because programmable cues can be harmonized with dynamic cellular responses. Here we present a lithography-free fabrication technique that can reversibly present topographical cues using an actuation mechanism that minimizes the confounding effects of applied stimuli. This method utilizes strain-induced buckling instabilities in bilayer substrate materials with rigid uniform silicon oxide membranes that are thermally deposited on elastomeric substrates. The resulting surfaces are capable of reversible of substrates between three distinct states: flat substrates (A = 1.53 ± 0.55 nm; Rms = 0.317 ± 0.048 nm); parallel wavy grating arrays (A∥= 483.6 ± 7.8 nm; λ∥= 4.78 ± 0.16 µm); perpendicular wavy grating arrays (A⊥= 429.3 ± 5.8 nm; λ⊥= 4.95 ± 0.36 µm). The cytoskeleton dynamics of 3T3 fibroblasts in response to these surfaces was measured using optical microscopy. Fibroblasts cultured on dynamic substrates that are switched from flat to topographic features (FLAT-WAVY) exhibit a robust and rapid change in gross morphology as measured by a reduction in circularity from 0.30 ± 0.13 to 0.15 ± 0.08 after 5 min. Conversely, dynamic substrate sequences of FLAT-WAVY-FLAT do not significantly alter the gross steady-state morphology. Taken together, substrates that present topographic structures reversibly can elucidate dynamic aspects of cell-topography interactions.


Assuntos
Materiais Biocompatíveis/química , Células 3T3-L1 , Animais , Camundongos , Propriedades de Superfície
15.
Adv Mater ; 26(5): 706-11, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24142533

RESUMO

Cost-effective materials for transparent conducting electrodes are essential for many devices used in clean energy production and consumer electronics. Here we report a technique for non-lithographic patterning of silver nanowires on flexible substrates from solution via microcontact transfer printing using donor substrates with reconfigurable topography. This approach is a highly scalable fabrication strategy for high performance transparent conductors.

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