Electrical Stimulation Of Cells Research Articles

Electrogenetic cellular insulin release for real-time glycemic control in type 1 diabetic mice.

Sophisticated devices for remote-controlled medical interventions require an electrogenetic interface that uses digital electronic input to directly program cellular behavior. We present a cofactor-free bioelectronic interface that directly links wireless-powered electrical stimulation of human cells to either synthetic promoter-driven transgene expression or rapid secretion of constitutively expressed protein therapeutics from vesicular stores. Electrogenetic control was achieved by coupling ectopic expression of the L-type voltage-gated channel CaV1.2 and the inwardly rectifying potassium channel Kir2.1 to the desired output through endogenous calcium signaling. Focusing on type 1 diabetes, we engineered electrosensitive human β cells (Electroβ cells). Wireless electrical stimulation of Electroβ cells inside a custom-built bioelectronic device provided real-time control of vesicular insulin release; insulin levels peaked within 10 minutes. When subcutaneously implanted, this electrotriggered vesicular release system restored normoglycemia in type 1 diabetic mice.

Electronic control of designer cells

Synthetic Biology There is increasing interest in using designer cells to produce or deliver therapeutics. Achieving direct communication between such cells and electronic devices would allow precise control of therapies. Krawczyk et al. describe a bioelectronic interface that uses wireless-powered electrical stimulation of cells to promote the release of insulin (see the Perspective by Brier and Dordick). The authors engineered human β cells to respond to membrane depolarization by rapidly releasing insulin from intracellular storage vesicles. A bioelectronic device that incorporates the cells can be wirelessly triggered by an external field generator. When subcutaneously implanted in type 1 diabetic mice, the device could be triggered to restore normal blood glucose levels. Science , this issue p. [993][1]; see also p. [936][2] [1]: /lookup/doi/10.1126/science.aau7187 [2]: /lookup/doi/10.1126/science.abb9122

Electrical vs Optical Cell Stimulation: A Communication Perspective

Over the recent years, an increasing amount of research effort has been directed toward the development and optimization of optical cell stimulation (OCS) techniques, while electrical cell stimulation (ECS) has been perfected. This article investigates the existing ECS and OCS methods from a communication perspective and, after summarizing the main breakthroughs in both fields, introduces a novel system model that treats the stimulation as a communication process. Additionally, we discuss the main particularities of ECS and OCS models and conduct a comparative analysis that quantifies the performance of the aforementioned methods based on suitable engineering metrics such as average latency, power consumption, transmission distance, as well as stimulation frequency, pulse width, and amplitude. Finally, future research directions emerge from the provided insightful discussion.

Role of potential-dependent potassium channels in forming the cellular response to the electrical stimulation of cells in the culture

Usage of electric fields for forming a certain cellular response finds application in various fields of biology and medicine. The efficiency of the methods based on the electric field action was discussed repeatedly. However, the process of developing stimulation protocols is being complicated by the absence of the specification of the precise mechanism of the electric stimulation action upon cells in the culture. Thus, the identification of signal transduction mechanism in cells under the electric field action is of current interest. The objective of this work is to investigate the role of potassium potential-dependent channels in forming the cellular response at long-term electrical stimulation. Studies were carried out using glioma cells C6. The pulsed electric field with the strength of 3-20 V/m, with 2 ms biphase pulses and with a frequency of 10 Hz was used for electric stimulation. 4-Aminopyridine was used for inhibitory analysis. It was shown that the change in the membrane potential under the electric field action takes place involving the potassium potential-dependent ion channels. It was revealed that the use of a potassium potential-dependent ion channels inhibitor partially levels the field effects. Thus, potassium potential-dependent channels play a significant role in the processes of signal transduction in cells at long-term electrical stimulation of the culture of cells.

Design, fabrication and testing of an electrical cell stimulation and recording apparatus (ECSARA) for cells in electroculture

A new dual-function electrical cell stimulation and recording apparatus (ECSARA) for simultaneously electrically stimulating cellular behavior within programmed stand-off electric fields (EFs) and monitoring cellular responses via AC electrical impedance spectroscopy (EIS) is reported. ECSARA is designed to have a footprint similar to that of a common 24-well cell culture plate within which each well is electrified via a pair of opposing planar titanium electrodes, within the cover (0.10 cm2) and base (0.50 cm2) of each well. Porous cell culture inserts established a 3-D milieu for bathing cells while keeping them away from unfavorable fields and forces in the vicinity of the electrodes. ECSARA was tested for its temporal stability, well-to-well variability, and responses in different media. EF modeling showed the field strength to be uniform in the subtending plane of the insert and the magnitude to be influenced by the porosity of the insert membrane. HUVECs were exposed to EF (162 mV/mm at 1.2 Hz) and monitored with standard viability Blue assay and EIS with equivalent circuit modeling. During the first 24 h, the viability (population) of EF-stimulated cells was smaller than non-stimulated control (0.8) but after 72 h they outnumbered the control (1.2) indicating that stimulation initially inhibited growth but resulted in eventual adaptive proliferation. EIS monitoring showed an increase in RCell of EF stimulated and control HUVECs after 54 h and 78 h, respectively. This was in accord with viability data that showed faster growth of EF-stimulated HUVECSs. Confluence was confirmed by VE-cadherin staining. The potential to explore the stimulatory influences of electric fields on cellular processes in tissue and regenerative engineering is now easily possible.

Membrane potential manipulation with visible flash lamp illumination of targeted microbeads

The electrical membrane potential (Vm) is a key dynamical variable of excitable membranes. Despite the tremendous success of optogenetic methods to modulate Vm with light, there are some shortcomings, such as the need of genetic manipulation and limited time resolution. Direct optical stimulation of gold nanoparticles targeted to cells is an attractive alternative because the absorbed energy heats the membrane and, thus, generates capacitive current sufficient to trigger action potentials [1, Carvalho-de-Souza et al., 2015]. However, focused laser light is required and precise location and binding of the nanoparticles cannot be assessed with a conventional microscope. We therefore examined a complementary method to manipulate Vm in a spatio-temporal fashion by non-focused visible flashlight stimulation (Xenon discharge lamp, 385-485 nm, ∼500 μs) of superparamagnetic microbeads. Flashlight stimulation of single beads targeted to cells resulted in transient inward currents under whole-cell patch-clamp control. The waveform of the current reflected the first time derivative of the local temperature induced by the absorbed light and subsequent heat dissipation. The maximal peak current as well as the temperature excursion scaled with the proximity to the plasma membrane. Transient illumination of light-absorbing beads, targeted to specific cellular sites via protein-protein interaction or direct micromanipulation, may provide means of rapid and spatially confined heating and electrical cell stimulation.

Requirements for Documenting Electrical Cell Stimulation Experiments for Replicability and Numerical Modeling∗.

Thorough documentation of biological experiments is necessary for their replicability. This becomes even more evident when individual steps of in vitro wet-lab experiments are to be incorporated into computer simulation models. In the highly interdisciplinary field of electrical stimulation of biological cells, not only biological but also physical aspects play a crucial role. Simulations may help to identify parameters that influence cells and thereby reveal new insights into mechanisms of the cell biological system. However, missing or misleading documentation of the electrical stimulation step within wet-lab experiments may lead to discrepancies between reported and simulated electrical quantities. In addition, this threatens the replicability of electrical stimulation experiments. Thus, we argue that a minimal set of information is needed to enable a translation of electrical stimulation experiments of biological cells into computer simulation experiments and to support replicability. This set includes detailed information about the electronic devices and components, their set-up as well as the applied stimulus and shall be integrated into an existing guideline for cell biological experiments. Ideally, the documentation should also contain measured properties of the cellular and experimental environment. Furthermore, a realization of our proposed documentation requirements within electronic lab notebooks may provide a crucial step toward a more seamless integration of wet-lab data into simulations. Based on two exemplary studies, we demonstrate the relevance of our claim.

Electrical Cell Stimulation: Fabrication of a Biocompatible Liquid Crystal Graphene Oxide–Gold Nanorods Electro‐ and Photoactive Interface for Cell Stimulation (Adv. Healthcare Mater. 9/2019)

Electrical Cell Stimulation: Fabrication of a Biocompatible Liquid Crystal Graphene Oxide–Gold Nanorods Electro‐ and Photoactive Interface for Cell Stimulation (Adv. Healthcare Mater. 9/2019)

Polyaniline Functionalized Graphene Nanoelectrodes for the Regeneration of PC12 Cells via Electrical Stimulation.

The regeneration of neurons is an important goal of neuroscience and clinical medicine. The electrical stimulation of cells is a promising technique to meet this goal. However, its efficiency highly depends on the electrochemical properties of the stimulation electrodes used. This work reports on the preparation and use of a highly electroactive and biocompatible nanoelectrode made from a novel polyaniline functionalized graphene composite. This nanocomposite was prepared using a facile and efficient polymerization-enhanced ball-milling method. It was used to stimulate the growth of PC12 cells under various electrical fields. The enhanced growth of axons and improved wound regeneration of PC12 cells were observed after this treatment, suggesting a promising strategy for neuro traumatology.

Electrical impulse effects on degenerative human annulus fibrosus model to reduce disc pain using micro-electrical impulse-on-a-chip

Electrical stimulation of cells and tissues for therapeutic benefit is a well-established method. Although animal studies can emulate the complexity of an organism’s physiology, lab-on-a-chip platforms provide a suitable primary model for follow-up animal studies. Thus, inexpensive and easy-to-use platforms for in vitro human cell studies are required. In the present study, we designed a micro-electrical impulse (micro-EI)-on-a-chip (micro-EI-chip), which can precisely control electron density and adjust the frequency based on a micro-EI. The micro-EI-chip can stimulate cells at various micro-EI densities (0–500 mV/mm) and frequencies (0–300 Hz), which enables multiple co-culture of different cell types with or without electrical stimulation. As a proof-of-concept study, a model involving degenerative inflamed human annulus fibrosus (hAF) cells was established in vitro and the effects of micro-EI on inflamed hAF cells were evaluated using the micro-EI-chip. Stimulation of the cells (150 mV/mm at 200 Hz) inhibited the secretion of inflammatory cytokines and downregulated the activities of extracellular matrix-modifying enzymes and matrix metalloproteinase-1. These results show that micro-EI stimulation could affect degenerative diseases based on inflammation, implicating the micro-EI-chip as being useful for basic research of electroceuticals.

Electrical stimulation of cells through photovoltaic microcell arrays

Electrical stimulation may influence cell behavior associated with proliferation, differentiation, and migration, among others. The need for electrical tools to interact with living cells has pushed the technology to progressively develop less invasive devices. Technologies like energy harvesting have enabled wireless biological applications. Here we report the use of a photovoltaic microcell array (PVMA) based on silicon, as a wire-free interface to stimulate single cells with high spatial resolution. We demonstrate the effectivity of this microtool on osteoblast cells. The electrical stimulation triggered intracellular calcium transients as a response in 46% of the cells. The reduced dimension of the PVMA and its capacity to work in visible light show its potential for the wireless life science explorations.

Soft, Wet and Ionic Microelectrode Systems

Abstract Engineering the interface between electric devices and ionic biosystems is of central importance to the advancement of biomedical devices. We have developed organic electrodes that are soft and moist like biological systems. Their larger interfacial capacitance is of advantage for the low-invasive electrical stimulation of cells and tissues without cytotoxic faradaic reactions. Conducting polymer-based composite electrodes developed here were useful for bioassay and medical treatments. The performance of enzyme-modified electrodes, which are the core component of biosensors and biofuel cells, was found to be greatly improved by utilizing nanostructures of carbon nanotubes (CNT). Self-powered sensors and skin patches were realized by using built-in biofuel cells with the CNT-based enzyme electrodes.

Biphasic Electrical Stimulation Promotes Insulin Release

Biphasic (anodal pulse followed immediately by a cathodal pulse) electrical stimulation (10Hz, 5 ms duration) of rat insulinoma (Ins‐1) cells resulted in a 2–3‐fold increase in insulin release over 30 min that was stimulation period‐ and voltage‐dependent. Electrical stimulation of tissue culture medium (in the absence of cells) did not increase insulin release when subsequently added to cells, confirming that the insulin released by electrical stimulation was not due to substances generated by the culture medium. Electrical stimulation‐induced insulin release occurred in the absence or presence of glucose. Calcium channel blockade (using nifedipine or verapamil) inhibited basal insulin secretion and insulin secretion evoked by electrical stimulation, demonstrating that electrical stimulation‐induced insulin release involved activation of voltage‐dependent calcium channels and was not a non‐specific effect of stimulation on the plasma membrane. Basal insulin secretion and the increase in insulin release induced by electrical stimulation were also inhibited by the mitochondrial poisons antimycin A or oligomycin A, suggesting a role for mitochondrial function in insulin secretion. Electrical stimulation of cells also resulted in a more pronounced uptake of MitoTracker Red by mitochondria, indicating a more negative inner mitochondrial membrane potential. The failure of cells to accumulate the fluorogenic dye Cytotox green confirmed that electrical stimulation was not significantly disrupting the plasma membrane or inducing overt toxicity to the cells during the period of stimulation. These results provide further evidence that biphasic electrical stimulation can exert significant biological effects and elicit insulin release in a manner that is dependent upon mitochondrial activity and calcium channel activation but independent of glucose.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Piezoelectric Effects of Materials on Bio-Interfaces.

Electrical stimulation of cells and tissues is an important approach of interaction with living matter, which has been traditionally exploited in the clinical practice for a wide range of pathological conditions, in particular, related to excitable tissues. Standard methods of stimulation are, however, often invasive, being based on electrodes and wires used to carry current to the intended site. The possibility to achieve an indirect electrical stimulation, by means of piezoelectric materials, is therefore of outstanding interest for all the biomedical research, and it emerged in the latest decade as a most promising tool in many bioapplications. In this paper, we summarize the most recent achievements obtained by our group and by others in the exploitation of piezoelectric nanoparticles and nanocomposites for cell stimulation, describing the important implications that these studies present in nanomedicine and tissue engineering. A particular attention will be also dedicated to the physical modeling, which can be extremely useful in the description of the complex mechanisms involved in the mechanical/electrical transduction, yet also to gain new insights at the base of the observed phenomena.

Fabrication and Characterization of Conductive Conjugated Polymer-Coated Antheraea mylitta Silk Fibroin Fibers for Biomedical Applications.

Conductive polymers are interesting materials for a number of biological and medical applications requiring electrical stimulation of cells or tissues. Highly conductive polymers (polypyrrole and polyaniline)/Antheraea mylitta silk fibroin coated fibers are fabricated successfully by in situ polymerization without any modification of the native silk fibroin. Coated fibers characterized by scanning electron microscopy confirm the silk fiber surface is covered by conductive polymers. Thermogravimetric analysis reveals preserved thermal stability of silk fiber after coating process. X-ray diffraction of degummed fiber diffraction peaks at around 2θ = 20.4 and 16.5 confirms the preservation of the β-sheet structure typical of degummed silk II fibers. This phenomenon implies that both polypyrrole and polyaniline chains form interactions with peptide linkages in degummed fiber macromolecules, without significantly disrupting protein assembly. Fourier transform infrared spectroscopy of coated fibers indicates hydrogen bonding and electrostatic interactions exist between silk fibroin macromolecules and conductive polymers. Resulting fibers display good conductive properties compared to corresponding conjugated polymers. In vitro analysis (live/dead assay) of the behavior of human immortalized keratinocytes (HaCaTs) on coated fibers demonstrates improved cell-adhesive properties and viability after polymers coating. Hence, polypyrrole- and polyaniline-coated A. mylitta silk fibers are suitable for application in cell culture and for tissue engineering, where electrical conduction properties are required.

Electromechanical Cell Stimulation: Stretchable Silver Nanowire Microelectrodes for Combined Mechanical and Electrical Stimulation of Cells (Adv. Healthcare Mater. 16/2016)

Electromechanical Cell Stimulation: Stretchable Silver Nanowire Microelectrodes for Combined Mechanical and Electrical Stimulation of Cells (Adv. Healthcare Mater. 16/2016)

Stretchable Silver Nanowire Microelectrodes for Combined Mechanical and Electrical Stimulation of Cells.

The use of stretchable electrodes interfaced with the human body has enabled a new frontier in biomedical engineering, and the miniaturization of such electrodes can allow for a more precise spatial control to monitor or stimulate tissues. The understanding of the response of cells or tissues to combined electromechanical stimulation, as made possible by stretchable electrodes, is essential to improve medical devices and therapies. Cheap to produce and easy to use platforms for in vitro cell studies are thus urgently needed. This study reports the successful implementation of silver nanowires (AgNWs) into an integrated miniaturized electromechanical stimulator, which is compatible with cell culture. The innovative steps include a lithography-based lift-off method to micropattern AgNWs onto an elastic silicone membrane. These stretchable microelectrodes are then integrated into a microfluidic device for cell culture, which enables the synchronous electromechanical stimulation of cells. In a proof-of-concept study, it is furthermore shown that fibroblasts respond uniquely to mechanical stretching, electrical stimulation, and combined electromechanical stimulations in terms of cell alignment and morphology, as well as by producing the extracellular matrix protein collagen. This proof-of-concept study illustrates the functionality and usability of these stretchable AgNWs microelectrodes for either basic research or future biomedical applications.

Electrical stimulation of cells in living bioelectronic devices

Electrical stimulation of cells in living bioelectronic devices

Electro-triggering and electrochemical monitoring of dopamine exocytosis from a single cell by using ultrathin electrodes based on Au nanowires

A sophisticated set of an Au nanowire (NW) stimulator-Au NW detector system is developed for electrical cell stimulation and electrochemical analysis of subsequent exocytosis with very high spatial resolution. Dopamine release from a rat pheochromocytoma cell is more stimulated by a more negative voltage pulse. This system could help to improve the therapeutic efficacy of electrotherapies by providing valuable information on their healing mechanism.

Development of a miniaturized stimulation device for electrical stimulation of cells.

BackgroundDirecting cell behaviour using controllable, on-demand non-biochemical methods, such as electrical stimulation is an attractive area of research. While there exists much potential in exploring different modes of electrical stimulation and investigating a wider range of cellular phenomena that can arise from electrical stimulation, progress in this field has been slow. The reasons for this are that the stimulation techniques and customized setups utilized in past studies have not been standardized, and that current approaches to study such phenomena rely on low throughput platforms with restricted variability of waveform outputs.ResultsHere, we first demonstrated how a variety of cellular responses can be elicited using different modes of DC and square waveform stimulation. Intracellular calcium levels were found to be elevated in the neuroblast cell line SH-SY5Y during stimulation with 5 V square waves and, stimulation with 150 mV/mm DC fields and 1.5 mA DC current resulted in polarization of protein kinase Akt in keratinocytes and elongation of endothelial cells, respectively. Next, a miniaturized stimulation device was developed with an integrated cell chamber array to output multiple discrete stimulation channels. A frequency dividing circuit implemented on the device provides a robust system to systematically study the effects of multiple output frequencies from a single input channel.ConclusionWe have shown the feasibility of directing cellular responses using various stimulation waveforms, and developed a modular stimulation device that allows for the investigation of multiple stimulation parameters, which previously had to be conducted with different discrete equipment or output channels. Such a device can potentially spur the development of other high throughput platforms for thorough investigation of electrical stimulation parameters on cellular responses.