1,720,982 research outputs found
A molecular dynamic study of cholesterol rich lipid membranes: Comparison of electroporation protocols
No full textA numerical design of versatile microchambers for nsPEFs experiments
No full textThe emergence of nanosecond pulsed electric fields (nsPEFs) for intracellular electro-manipulation experiments implies the application of extremely short (ns) high intensity (MV/m) electric field pulses. Specific pulse generators and miniaturized applicators are necessary to properly deliver this category of voltage signals to biological loads. In this context, we propose the design of a versatile nsPEFs applicator, developed following the guidelines typical of microwave propagating systems. The designed microchamber is suitable for in vitro exposure to undistorted pulses with duration down to 1-3 ns during single and multi cell experiments. Further features are: high efficiency (above 0.95), high cell viability by the integration of microfluidic components, real time monitoring of the biological sample and of the pulse propagation. These features can be considered as designing rules for new nanosecond and sub-nanosecond applicators, to ensure experimental repeatability and reproducibility when the impact of propagation on pulse signals is no more negligibl
Properties of lipid electropores I: Molecular dynamics simulations of stabilized pores by constant charge imbalance
No full textMolecular dynamics (MD) simulations have become a powerful tool to study electroporation (EP) in atomic detail. In the last decade, numerous MD studies have been conducted to model the effect of pulsed electric fields on membranes, providing molecular models of the EP process of lipid bilayers. Here we extend these investigations by modeling for the first time conditions comparable to experiments using long (mu s-ms) low intensity (similar to KV/cm) pulses, by studying the characteristics of pores formed in lipid bilayers maintained at a constant surface tension and subject to constant charge imbalance. This enables the evaluation of structural (size) and electrical (conductance) properties of the pores formed, providing information hardly accessible directly by experiments. Extensive simulations of EP of simple phosphatidylcholine bilayers in 1 M NaCl show that hydrophilic pores with stable radii (1-2.5 nm) form under transmembrane voltages between 420 and 630 mV, allowing for ionic conductance in the range of 6.4-29.5 nS. We discuss in particular these findings and characterize both convergence and size effects in the MD simulations. We further extend these studies in a follow-up paper (Rems et al., Bioelectrochemistry, Submitted), by proposing an improved continuum model of pore conductance consistent with the results from the MD simulations
Versatile broadband electrode assembly for cell electroporation
No full textIn this paper, a versatile electrode assembly for cell electroporation is proposed. For validation of the delivery system, biological cell electroporation experiments using 2.5 ns and 5 ns, 10 MV/m pulsed electric fields have been conducted. Electromagnetic, time domain, and frequency analyses demonstrate the broadband behavior of the delivery system. © 2012 IEEE
Molecular Dynamics Simulations of Ionic Transport in POPC Field-Stabilized Nanoscale Electropores
No full textMD simulations of transient water pores produced by transmembrane ionic Charge Imbalance in cholesterol containing bilayers
No full textMolecular dynamics simulations of ion conductance in field-stabilized nanoscale lipid electropores
No full textMolecular dynamics (MD) simulations of electrophoretic transport of monovalent ions through field-stabilized electropores in POPC lipid bilayers permit systematic characterization of the conductive properties of lipid nanopores. The radius of the electropore can be controlled by the magnitude of the applied sustaining external electric field, which also drives the transport of ions through the pore. We examined pore conductances for two monovalent salts, NaCl and KCl, at physiological concentrations. Na+ conductance is significantly less than K+ and Cl- conductance and is a nonlinear function of pore radius over the range of pore radii investigated. The single pore electrical conductance of KCl obtained from MD simulation is comparable to experimental values measured by chronopotentiometry. © 2013 American Chemical Society
A Molecular Dynamic (MD) insight to electrostatic of biological (lipid) bilayers. A tool for understanding electroporation mechanisms
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