Electrohydrodynamics of Vesicles and Capsules

Sinha, Kumari Priti; Das, Sudip; Karyappa, Rahul; Thaokar, Rochish

doi:10.1021/acs.langmuir.9b03971

Cited by 10 publications

(2 citation statements)

References 133 publications

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“…Their initial study on the local analysis of a planar membrane could predict highly non-linear pore formation and growth and the simultaneous coupled variation of the transmembrane potential. The physics of electroporation on a cellular level can be much more complex than those of a local small planar patch of the membrane, predominantly on account of spatial variation of the electric field [26, 7, 27, 18]. Using computational simulations, a number of studies demonstrated that for spherical biological cells, the TMP, pore number, and pore size are nonlinearly coupled, resulting in nonintuitive transient variations in TMP along the membrane [17, 14, 11, 34, 13].…”

Section: Introductionmentioning

confidence: 99%

Giant pore formation in vesicles under msPEF-induced electroporation: role of charging time and waveform

Behera,

Thaokar

2024

Preprint

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Giant unilamellar vesicle is the closest possible prototypical model for investigating membrane electrodeformation and electroporation in biological cells. In this paper, the effect of membrane charging time on vesicle electroporation, an unresolved issue, is exclusively investigated under milli-second pulsed-electric-field (msPEF) of different waveforms, using numerical simulations. The existing analytical models uncover several fundamental features of cell or vesicle electroporation, but remain far from being realistic as electrode-formation effects were neglected. Our numerical approach, which implements the effect of electric stretching on membrane tension and precise calculation of pore energy, successfully predicts the formation of giant pores ofO(µm) size as observed in past experiments. The poration zone is found to extend up to certain angles from the poles, termed critical angles. Increase in charging time delays pore formation, decreases the pore density as well as trim downs the poration zone. Counterintuitively, this effect promotes significant pore growth. Thus, more pores evolve into giant pores resulting in higher fractional pore area. Moreover, there exists a cut-off charging time above which pore formation is completely inhibited. This phenomenon is particularly pronounced with bipolar pulses. Comparisons with the past experimental results reveal that electrodeformation-poration-induced membrane surface area variation and that induced by electroporation evolves in a similar fashion. Therefore, although the agreements are qualitative, the present electroporation model can be used as the simplest tool to predict the transient electrodeformation of a porated vesicle in the laboratory experiments.

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Section: Introductionmentioning

confidence: 99%

Giant pore formation in vesicles under msPEF-induced electroporation: role of charging time and waveform

Behera,

Thaokar

2024

Preprint

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“…The vesicles, at such low fields, seldom electroporate and show (prolate or oblate) ellipsoid deformation dependent upon the frequency of the applied electric field and the conductivity ratio, α = σ in /σ out , where σ in and σ out are the conductivities of the inner and outer media, respectively. Several detailed reviews on this aspect can be found in the literature. − On the other hand, vesicles deformed into distinct shapes (disc for α < 1, square for α = 1, and tube for α > 1) when subjected to a strong DC pulsed (∼1–3 kV/cm) electric field. According to Riske and Dimova, electrophoretic forces as a result of the presence of the ions (>0.1 mM NaCl) in the suspending medium might be the reason behind the occurrence of these shapes.…”

Section: Introductionmentioning

confidence: 99%

Effect of the Waveform of the Pulsed Electric Field on the Cylindrical Deformation of Uncharged Giant Unilamellar Vesicles

Maoyafikuddin

Thaokar

2023

Langmuir

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High-speed imaging of giant unilamellar vesicles (GUVs) in recent years has shown significant shape deformation of these vesicles under electroporating direct current (DC) pulsed electric fields, possibly altering the surface distribution of transmembrane potential (TMP) and, thereby, the location and extent of electroporation on the bilayer membrane. The development of TMP, the corresponding shape deformation, and the extent of electroporation depend upon the waveform of the applied electric field. In this work, the deformation of vesicles was carried out under a high-intensity, single cycle of a sinusoidal pulsed electric field (SSPEF) and a square wave pulsed electric field (SWPEF). The cylindrical shape deformations of vesicles were observed for both SSPEF and SWPEF and were dependent upon the ratio of conductivity of the inner medium to the outer medium, α. For α = 1 and α > 1, the vesicles deformed into prolate cylinders as a result of Maxwell stress, whereas they were compressed into oblate cylinders for α < 1. Vesicles subjected to a SSPEF relaxed following either the pore closure dominated t 2 or the efflux and lipid loss dominated, slow t 3 mechanism depending upon the value of α. For α = 1 and α < 1, the relaxation of the vesicles was found to be predominantly dependent upon pore closure. On the other hand, a majority of vesicles gained excess area during poration when α > 1, which can be attributed to a higher TMP and faster charging of the membrane. The predictions of the approximate model for the deformation of vesicles agreed with the experiment, with deviations between the two as a result of the simplicity of the model. Moreover, the degree of deformation of vesicles [measured by the aspect ratio (AR)] and shape deformations of vesicles were found to be dependent upon the pulse width (T P) and amplitude (E 0) of the SSPEF. The specific temporal variation of pore-forming tendencies of SSPEF and SWPEF, with their associated peculiarities, can be judiciously used for controlling electroporation in cells and vesicles.

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Electrically Induced Bursting of Aqueous Capsules Made from Biopolymers: ‘Switching On’ the Release of Payloads

Gargava

Raghavan

2022

Adv Funct Materials

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The use of electric fields to stimulate the delivery of drugs or other active ingredients is of great interest for wearable electronics and other applications. Most attempts at electrically induced delivery with soft materials in water have focused on electronically conducting polymers (e.g., polypyrroles) or conductive nanocomposites (e.g., polymers with carbon nanotubes). Here, electrical responses are induced even in structures made from nonconducting biopolymers that are widely available, biocompatible, and biodegradable. The materials studied here are spherical capsules created from the anionic polysaccharide alginate by cross-linking with cations like Ca 2+ or Cu 2+ . When these capsules are placed in an aqueous solution and subjected to an electric field (direct current) of ≈8 V cm −1 , they deform within a couple of minutes and then burst and disintegrate into pieces within ≈5 min. Capsules across a range of length scales (200 µm to 2 cm) respond in the above manner, and the electroresponse persists even if the capsules are embedded in a nonionic gel matrix. This electroresponse is due to electrophoretic migration of charged species (ions and/or polyelectrolyte chain-segments) within (or out of ) the capsules. In an alginate capsule, the cations are induced to migrate away from the positive electrode, which creates a weakly cross-linked region of the capsule that swells appreciably. This anisotropic swelling continues until the capsule eventually bursts. Applications for electroresponsive capsules that highlight the spatial and temporal accuracy possible with an electrical stimulus are discussed. The bursting of capsules can be used to release solutes loaded inside these structures. Also, even the deformation of intact capsules can be used to create electrically actuatable valves, where a liquid flows out through the valve only when a capsule plug is dislodged.

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Electrohydrodynamics of Vesicles and Capsules

Cited by 10 publications

References 133 publications

Giant pore formation in vesicles under msPEF-induced electroporation: role of charging time and waveform

Giant pore formation in vesicles under msPEF-induced electroporation: role of charging time and waveform

Effect of the Waveform of the Pulsed Electric Field on the Cylindrical Deformation of Uncharged Giant Unilamellar Vesicles

Electrically Induced Bursting of Aqueous Capsules Made from Biopolymers: ‘Switching On’ the Release of Payloads

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