Nontoxic and durable salt bridges using hydroxyethylmethacrylate hydrogels

Kindler, Dean D.; Bergethon, Peter R.

doi:10.1152/jappl.1990.69.1.373

Cited by 5 publications

(5 citation statements)

References 7 publications

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“…Electrical stimulation was applied to the cell media via a pair of platinum electrodes, separated from the media by salt bridges formed from rectangular “plates” of poly-hydroxyethylmethacrylate (HEMA) hydrogel. These polymer hydrogel salt bridges were made according to the method of Kindler and Bergethon [1990]. In brief, HEMA hydrogels were prepared using a 1:1 volume:volume mixture of the HEMA monomer (S25464, Sigma Aldrich, St. Louis, MO) and 0.15 mol/l NaCl.…”

Section: Methodsmentioning

confidence: 99%

Electric fields caused by blood flow modulate vascular endothelial electrophysiology and nitric oxide production

Trivedi

Hallock

Bergethon

2012

Bioelectromagnetics

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Endothelial cells are exposed to a ubiquitous, yet unexamined electrical force caused by blood flow: the electrokinetic vascular streaming potential (EVSP). In this study, the hypothesis that extremely low frequency (ELF) electric fields parameterized by the EVSP have significant biological effects on endothelial cell properties was studied by measuring membrane potential and nitric oxide production under ELF stimulation between 0–2 Hz and 0–6.67 volts per meter. Using membrane potential and nitric oxide sensitive fluorescent dyes, bovine aortic endothelial cells (BAECs) in culture were studied in the presence and absence of EVSP-modeled electric fields. The transmembrane potential of BAECs was shown to depolarize between 1–7 mV with a strong dependency on both the magnitude and frequency of the isolated ELF field. The findings also support a field interaction with a frequency-dependent tuning curve. The ELF field complexly modulates the nitric oxide response to adenosine triphosphate stimulation with potentiation seen with up to a seven-fold increase. This potentiation was also frequency and magnitude dependent. An early logarithmic phase of NO production is enhanced in a field strength- dependent manner, but the ELF field does not modify a later exponential phase. This study shows that using electric fields on the order of those generated by blood flow influences the essential biology of endothelial cells. The inclusion of ELF electric fields in the paradigm of vascular biology may create novel opportunities for advancing both the understanding and therapies for treatment of vascular diseases.

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Section: Methodsmentioning

confidence: 99%

Electric fields caused by blood flow modulate vascular endothelial electrophysiology and nitric oxide production

Trivedi

Hallock

Bergethon

2012

Bioelectromagnetics

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“…In order to ensure isolation of electrode products from the cells, the electrical current was injected into the cell system through a pair of platinum electrodes separated from the cell culture system by salt bridges made of 0.15 M NaCl in hydroxyethylmethacrylate polymer [Kindler and Bergethon, 1990]. The sinusoidal waveform used in these experiments was generated by a signal generator (Circuitmate #FG2; Beckman Industrial, Brea, CA).…”

Section: Long-term Electric Field Application To Tissue Culturementioning

confidence: 99%

“…The output signal was fed through a unity gain follower circuit with a constant current of 40 mA delivered to the cultures. In order to ensure isolation of electrode products from the cells, the electrical current was injected into the cell system through a pair of platinum electrodes separated from the cell culture system by salt bridges made of 0.15 M NaCl in hydroxyethylmethacrylate polymer [Kindler and Bergethon, 1990]. Figure 1 shows the placement of pairs of salt bridges that allowed the injection of current into each flask so that the current flowed over and through the confluent layer of the smooth muscle cells.…”

Section: Long-term Electric Field Application To Tissue Culturementioning

confidence: 99%

Continuous exposure to low amplitude extremely low frequency electrical fields characterizing the vascular streaming potential alters elastin accumulation in vascular smooth muscle cells

Bergethon

Kindler

Hallock

et al. 2013

Bioelectromagnetics

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In normal development and pathology, the vascular system depends on complex interactions between cellular elements, biochemical molecules, and physical forces. The electrokinetic vascular streaming potential (EVSP) is an endogenous extremely low frequency (ELF) electrical field resulting from blood flowing past the vessel wall. While generally unrecognized, it is a ubiquitous electrical biophysical force to which the vascular tree is exposed. Extracellular matrix elastin plays a central role in normal blood vessel function and in the development of atherosclerosis. It was hypothesized that ELF fields of low amplitude would alter elastin accumulation, supporting a link between the EVSP and the biology of vascular smooth muscle cells. Neonatal rat aortic smooth muscle cell cultures were exposed chronically to electrical fields characteristic of the EVSP. Extracellular protein accumulation, DNA content, and electron microscopic (EM) evaluation were performed after 2 weeks of exposure. Stimulated cultures showed no significant change in cellular proliferation as measured by the DNA concentration. The per-DNA normalized protein in the extracellular matrix was unchanged while extracellular elastin accumulation decreased 38% on average. EM analysis showed that the stimulated cells had a 2.85-fold increase in mitochondrial number. These results support the formulation that ELF fields are a potential factor in both normal vessel biology and in the pathogenesis of atherosclerotic diseases including heart disease, stroke, and peripheral vascular disease.

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“…Hydrogels can also be made tough and flexible with desirable refractive indices (60). Hydrogels made of p(HEMA) in an electrolyte solution were used as a salt bridge which separate the metallic electrodes from the biological system to prevent contamination by electrolysis products (61). The p(HEMA) salt bridges are inexpensive, easy to make, easy to sterilize, very durable, and nontoxic to cell systems.…”

Section: Hydrogels In Bioapplicationsmentioning

confidence: 99%

Hydrogels in Bioapplications

Park

1996

ACS Symposium Series

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Research on hydrogels has been geared toward biomedical applications from the beginning due to their relatively high biocompatibility. Initially only the hydrophilic nature and the large swelling properties of hydrogels was explored. Continued research on hydrogels has resulted in the development of new types of hydrogels, such as environment-sensitive hydrogels, thermoplastic hydrogels, hydrogel foams, and sol-gel phase-reversible hydrogels. Application of hydrogels ranges from biomedical devices to solute separation. Examples of hydrogel applications in pharmaceutics, biomaterials, and biotechnology are briefly described.Hydrogel is a three-dimensional network of hydrophilic polymers in which a large amount of water is present. In general, the amount of water is at least 20% of the total weight. If water is composed of more than 95% of the total weight, then the hydrogel is called superabsorbent. The most characteristic property of hydrogel is that it swells in the presence of water and shrink in the absence of water. The extent of swelling is determined by the nature (mainly hydrophilicity) of polymer chains and the crosslinking density. If hydrogel is dried, the swollen network of the hydrogel is collapsed during drying due to the high surface tension of water. Thus, the dried hydrogel (or xerogel) becomes much smaller in size than the hydrogel swollen in water. During swelling and shrinking process, hydrogels can preserve its overall shape.To maintain the three-dimensional structures, polymer chains of hydrogels are usually crosslinked either chemically or physically. In chemical gels polymer chains are connected by covalent bonds, and thus it is difficult to change the shape of chemical gels. On the other hand, polymer chains of physical gels are connected through non-covalent bonds, such as van der Waals interactions, ionic interactions, hydrogen bonding, or hydrophobic interactions (1). Since the bonding between polymer chains are reversible, physical gels possess sol-gel reversibility. For example, sodium alginate becomes a gel in the presence of calcium ions, but the gel becomes sol if the divalent cations are removed.Strong interest in biomedical applications of hydrogels was caused by the landmark paper by Wichterle and Lim on poly(2-hydroxyethyl methacrylate) or p(HEMA)(2). Since then the research on hydrogel has been steadily increased. It is

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Nontoxic and durable salt bridges using hydroxyethylmethacrylate hydrogels

Cited by 5 publications

References 7 publications

Electric fields caused by blood flow modulate vascular endothelial electrophysiology and nitric oxide production

Electric fields caused by blood flow modulate vascular endothelial electrophysiology and nitric oxide production

Continuous exposure to low amplitude extremely low frequency electrical fields characterizing the vascular streaming potential alters elastin accumulation in vascular smooth muscle cells

Hydrogels in Bioapplications

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