Base de dados : MEDLINE
Pesquisa : E05.196.867.335 [Categoria DeCS]
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  1 / 1745 MEDLINE  
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[PMID]:29351332
[Au] Autor:Grebenko A; Dremov V; Barzilovich P; Bubis A; Sidoruk K; Voeikova T; Gagkaeva Z; Chernov T; Korostylev E; Gorshunov B; Motovilov K
[Ad] Endereço:Moscow Institute of Physics and Technology, Institute lane 9, Dolgoprudny, Russian Federation.
[Ti] Título:Impedance spectroscopy of single bacterial nanofilament reveals water-mediated charge transfer.
[So] Source:PLoS One;13(1):e0191289, 2018.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:For decades respiratory chain and photosystems were the main firing field of the studies devoted to mechanisms of electron transfer in proteins. The concept of conjugated lateral electron and transverse proton transport during cellular respiration and photosynthesis, which was formulated in the beginning of 1960-s, has been confirmed by thousands of experiments. However, charge transfer in recently discovered bacterial nanofilaments produced by various electrogenic bacteria is regarded currently outside of electron and proton conjugation concept. Here we report the new study of charge transfer within nanofilaments produced by Shewanella oneidensis MR-1 conducted in atmosphere of different relative humidity (RH). We utilize impedance spectroscopy and DC (direct current) transport measurements to find out the peculiarities of conductivity and Raman spectroscopy to analyze the nanofilaments' composition. Data analysis demonstrates that apparent conductivity of nanofilaments has crucial sensitivity to humidity and contains several components including one with unusual behavior which we assign to electron transport. We demonstrate that in the case of Shewanella oneidensis MR-1 charge transfer within these objects is strongly mediated by water. Basing on current data analysis of conductivity we conclude that the studied filaments of Shewanella oneidensis MR-1 are capable of hybrid (conjugated) electron and ion conductivity.
[Mh] Termos MeSH primário: Shewanella/metabolismo
Água/metabolismo
[Mh] Termos MeSH secundário: Citocromos/química
Citocromos/metabolismo
Espectroscopia Dielétrica
Transporte de Elétrons
Heme/metabolismo
Umidade
Shewanella/citologia
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Cytochromes); 059QF0KO0R (Water); 42VZT0U6YR (Heme)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180226
[Lr] Data última revisão:
180226
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180120
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0191289


  2 / 1745 MEDLINE  
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[PMID]:28462905
[Au] Autor:David M; Levy E; Feldman Y; Ben Ishai P; Zelig O; Yedgar S; Barshtein G
[Ad] Endereço:Applied Physics Department, The Hebrew University of Jerusalem, Jerusalem, Israel.
[Ti] Título:The dielectric spectroscopy of human red blood cells: the differentiation of old from fresh cells.
[So] Source:Physiol Meas;38(7):1335-1348, 2017 Jun 22.
[Is] ISSN:1361-6579
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:OBJECTIVE: The objective of the study was to gauge the effect of storage lesions on the dielectric response of red blood cells (RBC), in particular those processes linked to deformations of the cellular membrane known as the ß-dispersion. APPROACH: The dielectric response of RBC suspensions, exposed to blood-bank cold storage, was studied using time-domain dielectric spectroscopy (TDDS) in the frequency range of 500 kHz up to 1 GHz. The measured dielectric processes are characterized by their dielectric strength (Δε) and relaxation time (τ). Changes in the dielectric properties of the RBC suspensions due to storage-related lesions were evaluated. For a quantitative characterization of RBC lesions, we measured the deformability of fresh and stored RBC as expressed by their elongation ratio (ER), which was achieved under a shear stress of 3.0 Pa. MAIN RESULT: The results show that the storage of RBC induced a statistically significant decrease of dielectric relaxation times. In addition, a sound correlation between the mean values of ER and the relaxation times was observed (Spearman's correlation coefficient ρ = 0.847). We draw the conclusion that those alterations in the relaxation time are induced by changes in the shape of the RBC that happen during cold-storage. SIGNIFICANCE: The evolution of the ß-dispersion of RBC opens new possibilities in the blood bank inventory management.
[Mh] Termos MeSH primário: Diferenciação Celular
Espectroscopia Dielétrica
Eritrócitos/citologia
[Mh] Termos MeSH secundário: Criopreservação
Espectroscopia Dielétrica/instrumentação
Eletrodos
Seres Humanos
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180221
[Lr] Data última revisão:
180221
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170503
[St] Status:MEDLINE
[do] DOI:10.1088/1361-6579/aa707a


  3 / 1745 MEDLINE  
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[PMID]:28470522
[Au] Autor:Christ B; Fey C; Cubukova A; Walles H; Dembski S; Metzger M
[Ad] Endereço:Translational Center Würzburg "Regenerative Therapies for Oncology and Musculosceletal Diseases", Branch of Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, Würzburg, 97070, Germany.
[Ti] Título:Screening Applications to Test Cellular Fitness in Transwell Models After Nanoparticle Treatment.
[So] Source:Methods Mol Biol;1601:111-122, 2017.
[Is] ISSN:1940-6029
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Nanoparticles (NPs) in biotechnology hold great promise for revolutionizing medical treatments and therapies. In order to bring NPs into clinical application there is a number of preclinical in vitro and in vivo tests, which have to be applied before. The initial in vitro evaluation includes a detailed physicochemical characterization as well as biocompatibility tests, among others. For determination of biocompatibility at the cellular level, the correct choice of the in vitro assay as well as NP pretreatment is absolutely essential. There are a variety of assay technologies available that use standard plate readers to measure metabolic markers to estimate the number of viable cells in culture. Each cell viability assay has its own set of advantages and disadvantages. Regardless of the assay method chosen, the major factors critical for reproducibility and success include: (1) choosing the right assay after comparing optical NP properties with the read-out method of the assay, (2) verifying colloidal stability of NPs in cell culture media, (3) preparing a sterile and stable NP dispersion in cell culture media used in the assay, (4) using a tightly controlled and consistent cell model allowing appropriate characterization of NPs. This chapter will briefly summarize these different critical points, which can occur during biocompatibility screening applications of NPs.
[Mh] Termos MeSH primário: Sobrevivência Celular/efeitos dos fármacos
Teste de Materiais/métodos
Nanopartículas/química
Nanopartículas/toxicidade
[Mh] Termos MeSH secundário: Células CACO-2
Coloides/química
Meios de Cultura/química
Espectroscopia Dielétrica
Sistemas de Liberação de Medicamentos
Seres Humanos
Concentração de Íons de Hidrogênio
Tamanho da Partícula
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Colloids); 0 (Culture Media)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180219
[Lr] Data última revisão:
180219
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170505
[St] Status:MEDLINE
[do] DOI:10.1007/978-1-4939-6960-9_10


  4 / 1745 MEDLINE  
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[PMID]:28749490
[Au] Autor:Dmitrieva OA; Fedotova MV; Buchner R
[Ad] Endereço:G.A. Krestov Institute of Solution Chemistry, Russian Academy of Sciences, Akademicheskaya st. 1, 153045 Ivanovo, Russian Federation. hebrus@mail.ru.
[Ti] Título:Evidence for cooperative Na and Cl binding by strongly hydrated l-proline.
[So] Source:Phys Chem Chem Phys;19(31):20474-20483, 2017 Aug 09.
[Is] ISSN:1463-9084
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:In nature the amino acid l-proline (Pro) is a ubiquitous and highly effective osmolyte protecting cells against osmotic stress. To understand this effect knowledge of the hydration of Pro and its interactions with dissolved salts is essential. We studied these properties by combining statistical mechanics and broadband dielectric spectroscopy and found that Pro remains strongly hydrated up to high amino-acid concentrations. This is also the case upon NaCl addition to a 0.6 M Pro solution. Here, additionally a Pro·NaCl aggregate is formed with a stability constant of K° ≈ 0.95…1.25 M , where Na and Cl cooperatively bind to adjacent carboxylate-oxygen and ammonium-hydrogen atoms, respectively.
[Mh] Termos MeSH primário: Cloretos/química
Prolina/química
Sódio/química
[Mh] Termos MeSH secundário: Espectroscopia Dielétrica
Íons/química
Conformação Molecular
Pressão Osmótica
Água/química
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Chlorides); 0 (Ions); 059QF0KO0R (Water); 9DLQ4CIU6V (Proline); 9NEZ333N27 (Sodium)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180212
[Lr] Data última revisão:
180212
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170728
[St] Status:MEDLINE
[do] DOI:10.1039/c7cp04335j


  5 / 1745 MEDLINE  
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[PMID]:29177311
[Au] Autor:Zhang C; Yang M; Zhao K
[Ad] Endereço:College of Chemistry, Beijing Normal University, Beijing 100875, China. zhaoks@bnu.edu.cn.
[Ti] Título:Insight into the effect mechanism of urea-induced protein denaturation by dielectric spectroscopy.
[So] Source:Phys Chem Chem Phys;19(47):32007-32015, 2017 Dec 06.
[Is] ISSN:1463-9084
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Dielectric relaxation spectroscopy was applied to study how urea affects the phase transition of a thermosensitive polymer, poly(N-isopropylacrylamide) (PNIPAM), which has been widely used as a protein model. It was found that there is a pronounced relaxation near 10 GHz for the ternary system of PNIPAM in urea aqueous solution. The temperature dependence of dielectric parameters indicates that urea can reduce the lower critical solution temperature (LCST) of PNIPAM, i.e., stabilize the globule state of PNIPAM and collapse the PNIPAM chains. Based on our results, the interaction mechanism of urea on the conformational transition of PNIPAM was presented: urea replaces water molecules directly bonding with PNIPAM and acts as the bridging agent for the adjacent side chains of PNIPAM. Accordingly, the mechanism with which urea denatures protein was deduced. In addition, it is worth mentioning that, from the temperature dependence of the dielectric parameters obtained in the presence of urea, an interesting phenomenon was found in which the effect of urea on PNIPAM seems to take 2 M as a unit. This result may be the reason why urea and TMAO exit marine fishes at a specific ratio of 2 : 1.
[Mh] Termos MeSH primário: Resinas Acrílicas/química
Espectroscopia Dielétrica
Desnaturação Proteica
Ureia/química
[Mh] Termos MeSH secundário: Animais
Peixes
Conformação Proteica
Estabilidade Proteica
Temperatura Ambiente
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Acrylic Resins); 25189-55-3 (poly-N-isopropylacrylamide); 8W8T17847W (Urea)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180205
[Lr] Data última revisão:
180205
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171128
[St] Status:MEDLINE
[do] DOI:10.1039/c7cp05994a


  6 / 1745 MEDLINE  
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[PMID]:28462825
[Au] Autor:Haba Y; Wurm A; Köckerling M; Schick C; Mittelmeier W; Bader R
[Ad] Endereço:University Medicine Rostock, Department of Orthopaedics, Biomechanics and Implant Technology Research Laboratory Rostock, Germany. Electronic address: Yvonne.Haba@uni-rostock.de.
[Ti] Título:Characterization of human cancellous and subchondral bone with respect to electro physical properties and bone mineral density by means of impedance spectroscopy.
[So] Source:Med Eng Phys;45:34-41, 2017 Jul.
[Is] ISSN:1873-4030
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Computational simulation of electrical bone stimulation of the electrical and dielectric parameters of osteoarthritic bone tissue is useful for an exact patient-individual adaptation of the bone models. Therefore, we investigated electrical and dielectric parameters at a frequency of 20Hz of cancellous and subchondral human femoral head bone samples. Furthermore, the mechanical properties and the bone mineral density (BMD) were determined. Finally, these data were compared with the electrical and dielectric parameters. The bone samples were taken from patients with hip osteoarthritis. Electrical conductivity and dielectric permittivity of cancellous bone amounted to 0.043S/m and 8.1â‹…10 . BMD of the bone samples determined by dual-x-ray-absorptiometry (DXA) and ashing resulted in 193 ± 70mg/cm² and 286 ± 59mg/cm³ respectively. Structural modulus (E ) and ultimate compression strength (σ ) were measured with 227 ± 94N/mm² and 6.5 ± 3.4N/mm². No linear correlation of the electrical and dielectric parameters compared with BMD and mechanical properties of cancellous bone samples was found. Electrical conductivity and dielectric permittivity of subchondral bone resulted in 0.029S/m and 8.97×10 .
[Mh] Termos MeSH primário: Densidade Óssea
Osso Esponjoso/fisiologia
Fenômenos Eletrofisiológicos
[Mh] Termos MeSH secundário: Idoso
Idoso de 80 Anos ou mais
Osso Esponjoso/fisiopatologia
Espectroscopia Dielétrica
Feminino
Seres Humanos
Masculino
Meia-Idade
Osteoartrite/fisiopatologia
Temperatura Ambiente
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1801
[Cu] Atualização por classe:180108
[Lr] Data última revisão:
180108
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170503
[St] Status:MEDLINE


  7 / 1745 MEDLINE  
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[PMID]:28448273
[Au] Autor:Wang JY; Healey T; Barker A; Brown B; Monk C; Anumba D
[Ad] Endereço:Academic Unit of Reproductive and Development Medicine, Jessop Wing, University of Sheffield and Sheffield Teaching Hospitals NHS Trust, Sheffield S10 2SF, United Kingdom.
[Ti] Título:Magnetic induction spectroscopy (MIS)-probe design for cervical tissue measurements.
[So] Source:Physiol Meas;38(5):729-744, 2017 May.
[Is] ISSN:1361-6579
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:OBJECTIVE: Gradiometers have the advantage of increasing measuring sensitivity, which is particularly useful in magnetic induction spectroscopy (MIS) for bio-impedance measurements. Traditional gradiometers use a pair of field sensing coils equally distant and on opposite sides of a drive coil, which provides high immunity to interference. In this paper, a ferrite-cored coaxial gradiometer probe of 29 mm diameter has been developed for measuring the impedance spectra of cervical tissues in vivo. APPROACH: It consists of a ferrite rod with outer ferrite confinement screening in order to eliminate the signals from surrounding tissue. The magnetic screening efficiency was compared with an air-cored gradiometer probe. For both gradiometer probes, a drive coil and two sensing coils were wound on a borosilicate glass former aligned coaxially with two sensing coils equidistant from the drive coil. The signal sensitivity of those two MIS gradiometers has been measured using saline samples with a conductivity range between 0.1 and 1.1 S m . Finite element methods using COMSOL Multiphysics have been used to simulate the distribution of sensitivity to conductivity over the face of each probe and with depth. MAIN RESULTS: The ferrite-cored probe has a sensitivity confined to the volume defined by the gap between the ferrite core and outer tube of ferrite while the air-cored probe without any magnetic shielding had a wide sensitivity over the face and the side of the probe. Four saline samples and one of distilled water with conductivities from 0.1 to 1.1 S m have been used to make conductivity measurements at frequencies of 50 kHz, 100 kHz, and 300 kHz. The measurement accuracy of the air-cored MIS probe was 0.09 S m at 50 kHz, improving to 0.05 S m at 300 kHz. For the ferrite-cored MIS probe, the measurement accuracy was 0.28 S m at 50 kHz, improving to 0.04 S m at 300 kHz. SIGNIFICANCE: In vivo measurements on human hand have been performed using both types of gradiometers and the conductivity is consistent with reported data.
[Mh] Termos MeSH primário: Colo do Útero/citologia
Espectroscopia Dielétrica/instrumentação
Fenômenos Magnéticos
[Mh] Termos MeSH secundário: Ar
Desenho de Equipamento
Feminino
Compostos Férricos
Análise de Elementos Finitos
Antebraço
Mãos
Seres Humanos
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Ferric Compounds); 1317-54-0 (ferrite)
[Em] Mês de entrada:1712
[Cu] Atualização por classe:171221
[Lr] Data última revisão:
171221
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170428
[St] Status:MEDLINE
[do] DOI:10.1088/1361-6579/aa6b4e


  8 / 1745 MEDLINE  
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[PMID]:28957374
[Au] Autor:Liew JWY; Loh KS; Ahmad A; Lim KL; Wan Daud WR
[Ad] Endereço:Fuel Cell Institute, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia.
[Ti] Título:Synthesis and characterization of modified κ-carrageenan for enhanced proton conductivity as polymer electrolyte membrane.
[So] Source:PLoS One;12(9):e0185313, 2017.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Polymer electrolyte membranes based on the natural polymer κ-carrageenan were modified and characterized for application in electrochemical devices. In general, pure κ-carrageenan membranes show a low ionic conductivity. New membranes were developed by chemically modifying κ-carrageenan via phosphorylation to produce O-methylene phosphonic κ-carrageenan (OMPC), which showed enhanced membrane conductivity. The membranes were prepared by a solution casting method. The chemical structure of OMPC samples were characterized using Fourier transform infrared spectroscopy (FTIR), 1H nuclear magnetic resonance (1H NMR) spectroscopy and 31P nuclear magnetic resonance (31P NMR) spectroscopy. The conductivity properties of the membranes were investigated by electrochemical impedance spectroscopy (EIS). The characterization demonstrated that the membranes had been successfully produced. The ionic conductivity of κ-carrageenan and OMPC were 2.79 × 10-6 S cm-1 and 1.54 × 10-5 S cm-1, respectively. The hydrated membranes showed a two orders of magnitude higher ionic conductivity than the dried membranes.
[Mh] Termos MeSH primário: Carragenina/química
Carragenina/síntese química
Eletrólitos/química
Membranas Artificiais
Polímeros/química
Prótons
[Mh] Termos MeSH secundário: Varredura Diferencial de Calorimetria
Espectroscopia Dielétrica
Condutividade Elétrica
Microscopia Eletrônica de Varredura
Espectroscopia de Prótons por Ressonância Magnética
Espectrometria por Raios X
Temperatura Ambiente
Termogravimetria
Difração de Raios X
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Electrolytes); 0 (Membranes, Artificial); 0 (Polymers); 0 (Protons); 9000-07-1 (Carrageenan)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171018
[Lr] Data última revisão:
171018
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170929
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0185313


  9 / 1745 MEDLINE  
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[PMID]:28902883
[Au] Autor:Kim JS; Yang JW; Yoo JS; Choi SO; Han BG
[Ad] Endereço:Department of Nephrology, Yonsei University Wonju College of Medicine, Wonju, Kang-won, Korea.
[Ti] Título:Association between E/e´ ratio and fluid overload in patients with predialysis chronic kidney disease.
[So] Source:PLoS One;12(9):e0184764, 2017.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:BACKGROUND: Chronic fluid overload is common in patients with chronic kidney disease (CKD) and can with time lead to diastolic dysfunction and heart failure. We investigated whether markers of fluid status, such as NT-proBNP and bioimpedance spectroscopy (BIS), can predict echocardiographic findings of diastolic dysfunction in non-dialysis CKD5 patients. METHODS: BIS, echocardiography, and measurement of serum NT-proBNP were performed in patients with non-dialysis CKD stage 5 at a single study visit. E/e´ ratio reflect mean LV diastolic pressure and a ratio greater than 15 was used as a definition of diastolic dysfunction. RESULTS: Eighty-four patients were analyzed. Forty-six patients (54.76%) had E/e´ ratio ≤15 and 38 patients (45.24%) had E/e´ > 15 (diastolic dysfunction). Patients with E/e´>15 had significantly higher serum NT-proBNP (14,650 pg/mL) than patients with to E/e´≤15 (4,271 pg/mL) and had more overhydration (OH), 5.1 liters compared to 2.4 liters. The cut-off values predicting diastolic dysfunction were found to be 2,797 pg/mL for NT-proBNP and 2.45 liters for OH. CONCLUSIONS: Regular monitoring of fluid status by BIS and NT-proBNP can be used to find patient with risk of developing diastolic dysfunction. Treatments to correct fluid overload may reduce the risk of developing diastolic dysfunction and improve cardiovascular outcome in patients with CKD.
[Mh] Termos MeSH primário: Insuficiência Cardíaca Diastólica/diagnóstico
Insuficiência Renal Crônica/complicações
[Mh] Termos MeSH secundário: Pressão Sanguínea
Espectroscopia Dielétrica/métodos
Ecocardiografia
Insuficiência Cardíaca Diastólica/complicações
Insuficiência Cardíaca Diastólica/diagnóstico por imagem
Seres Humanos
Modelos Lineares
Peptídeo Natriurético Encefálico/sangue
Fragmentos de Peptídeos/sangue
Insuficiência Renal Crônica/metabolismo
Insuficiência Renal Crônica/patologia
Estudos Retrospectivos
Disfunção Ventricular Esquerda/complicações
Disfunção Ventricular Esquerda/diagnóstico
Disfunção Ventricular Esquerda/fisiopatologia
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Peptide Fragments); 0 (pro-brain natriuretic peptide (1-76)); 114471-18-0 (Natriuretic Peptide, Brain)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171024
[Lr] Data última revisão:
171024
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170914
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0184764


  10 / 1745 MEDLINE  
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[PMID]:28678160
[Au] Autor:Khan MS; Dosoky NS; Patel D; Weimer J; Williams JD
[Ad] Endereço:Electrical and Computer Engineering Department, University of Alabama in Huntsville, Huntsville, AL 35899, USA. mskhan7@illinois.edu.
[Ti] Título:Lipid Bilayer Membrane in a Silicon Based Micron Sized Cavity Accessed by Atomic Force Microscopy and Electrochemical Impedance Spectroscopy.
[So] Source:Biosensors (Basel);7(3), 2017 Jul 05.
[Is] ISSN:2079-6374
[Cp] País de publicação:Switzerland
[La] Idioma:eng
[Ab] Resumo:Supported lipid bilayers (SLBs) are widely used in biophysical research to probe the functionality of biological membranes and to provide diagnoses in high throughput drug screening. Formation of SLBs at below phase transition temperature ( ) has applications in nano-medicine research where low temperature profiles are required. Herein, we report the successful production of SLBs at above-as well as below-the of the lipids in an anisotropically etched, silicon-based micro-cavity. The Si-based cavity walls exhibit controlled temperature which assist in the quick and stable formation of lipid bilayer membranes. Fusion of large unilamellar vesicles was monitored in real time in an aqueous environment inside the Si cavity using atomic force microscopy (AFM), and the lateral organization of the lipid molecules was characterized until the formation of the SLBs. The stability of SLBs produced was also characterized by recording the electrical resistance and the capacitance using electrochemical impedance spectroscopy (EIS). Analysis was done in the frequency regime of 10 -105 Hz at a signal voltage of 100 mV and giga-ohm sealed impedance was obtained continuously over four days. Finally, the cantilever tip in AFM was utilized to estimate the bilayer thickness and to calculate the rupture force at the interface of the tip and the SLB. We anticipate that a silicon-based, micron-sized cavity has the potential to produce highly-stable SLBs below their . The membranes inside the Si cavity could last for several days and allow robust characterization using AFM or EIS. This could be an excellent platform for nanomedicine experiments that require low operating temperatures.
[Mh] Termos MeSH primário: Membrana Celular/química
Bicamadas Lipídicas/química
Nanomedicina
Fosfatidilcolinas/isolamento & purificação
[Mh] Termos MeSH secundário: Anisotropia
Biofísica
Espectroscopia Dielétrica/métodos
Seres Humanos
Bicamadas Lipídicas/isolamento & purificação
Microscopia de Força Atômica/métodos
Transição de Fase
Fosfatidilcolinas/química
Silício/química
Temperatura Ambiente
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Lipid Bilayers); 0 (Phosphatidylcholines); Z4152N8IUI (Silicon)
[Em] Mês de entrada:1707
[Cu] Atualização por classe:171001
[Lr] Data última revisão:
171001
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170706
[St] Status:MEDLINE



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BIREME/OPAS/OMS - Centro Latino-Americano e do Caribe de Informação em Ciências da Saúde