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Shaner S, Lu H, Lenz M, Garg S, Vlachos A, Asplund M. Brain stimulation-on-a-chip: a neuromodulation platform for brain slices. LAB ON A CHIP 2023; 23:4967-4985. [PMID: 37909911 PMCID: PMC10661668 DOI: 10.1039/d3lc00492a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 10/15/2023] [Indexed: 11/03/2023]
Abstract
Electrical stimulation of ex vivo brain tissue slices has been a method used to understand mechanisms imparted by transcranial direct current stimulation (tDCS), but there are significant direct current electric field (dcEF) dosage and electrochemical by-product concerns in conventional experimental setups that may impact translational findings. Therefore, we developed an on-chip platform with fluidic, electrochemical, and magnetically-induced spatial control. Fluidically, the chamber geometrically confines precise dcEF delivery to the enclosed brain slice and allows for tissue recovery in order to monitor post-stimulation effects. Electrochemically, conducting hydrogel electrodes mitigate stimulation-induced faradaic reactions typical of commonly-used metal electrodes. Magnetically, we applied ferromagnetic substrates beneath the tissue and used an external permanent magnet to enable in situ rotational control in relation to the dcEF. By combining the microfluidic chamber with live-cell calcium imaging and electrophysiological recordings, we showcased the potential to study the acute and lasting effects of dcEFs with the potential of providing multi-session stimulation. This on-chip bioelectronic platform presents a modernized yet simple solution to electrically stimulate explanted tissue by offering more environmental control to users, which unlocks new opportunities to conduct thorough brain stimulation mechanistic investigations.
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Affiliation(s)
- Sebastian Shaner
- Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg im Breisgau, Germany
- BrainLinks-BrainTools Center, University of Freiburg, Georges-Köhler-Allee 201, 79110 Freiburg im Breisgau, Germany
| | - Han Lu
- BrainLinks-BrainTools Center, University of Freiburg, Georges-Köhler-Allee 201, 79110 Freiburg im Breisgau, Germany
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Albertstraße 17, 79104 Freiburg im Breisgau, Germany.
| | - Maximilian Lenz
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Albertstraße 17, 79104 Freiburg im Breisgau, Germany.
- Hannover Medical School, Institute of Neuroanatomy and Cell Biology, Carl-Neuberg-Straße 1, 30625 Hannover, Germany
| | - Shreyash Garg
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Albertstraße 17, 79104 Freiburg im Breisgau, Germany.
- MSc Neuroscience Program, Faculty of Biology, University of Freiburg, Schänzlestraße 1, 79104 Freiburg im Breisgau, Germany
| | - Andreas Vlachos
- BrainLinks-BrainTools Center, University of Freiburg, Georges-Köhler-Allee 201, 79110 Freiburg im Breisgau, Germany
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Albertstraße 17, 79104 Freiburg im Breisgau, Germany.
- Center for Basics in Neuromodulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, 79104 Freiburg im Breisgau, Germany
| | - Maria Asplund
- Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg im Breisgau, Germany
- BrainLinks-BrainTools Center, University of Freiburg, Georges-Köhler-Allee 201, 79110 Freiburg im Breisgau, Germany
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, Chalmersplatsen 4, 41258 Gothenburg, Sweden.
- Division of Nursing and Medical Technology, Luleå University of Technology, 79187 Luleå, Sweden
- Freiburg Institute for Advanced Studies (FRIAS), University of Freiburg, Albertstraße 19, 79104 Freiburg im Breisgau, Germany
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2
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Matter L, Harland B, Raos B, Svirskis D, Asplund M. Generation of direct current electrical fields as regenerative therapy for spinal cord injury: A review. APL Bioeng 2023; 7:031505. [PMID: 37736015 PMCID: PMC10511262 DOI: 10.1063/5.0152669] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 08/21/2023] [Indexed: 09/23/2023] Open
Abstract
Electrical stimulation (ES) shows promise as a therapy to promote recovery and regeneration after spinal cord injury. ES therapy establishes beneficial electric fields (EFs) and has been investigated in numerous studies, which date back nearly a century. In this review, we discuss the various engineering approaches available to generate regenerative EFs through direct current electrical stimulation and very low frequency electrical stimulation. We highlight the electrode-tissue interface, which is important for the appropriate choice of electrode material and stimulator circuitry. We discuss how to best estimate and control the generated field, which is an important measure for comparability of studies. Finally, we assess the methods used in these studies to measure functional recovery after the injury and treatment. This work reviews studies in the field of ES therapy with the goal of supporting decisions regarding best stimulation strategy and recovery assessment for future work.
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Affiliation(s)
- Lukas Matter
- Author to whom correspondence should be addressed:
| | - Bruce Harland
- School of Pharmacy, The University of Auckland, NZ 1023 Auckland, New Zealand
| | - Brad Raos
- School of Pharmacy, The University of Auckland, NZ 1023 Auckland, New Zealand
| | - Darren Svirskis
- School of Pharmacy, The University of Auckland, NZ 1023 Auckland, New Zealand
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3
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Shaner S, Savelyeva A, Kvartuh A, Jedrusik N, Matter L, Leal J, Asplund M. Bioelectronic microfluidic wound healing: a platform for investigating direct current stimulation of injured cell collectives. LAB ON A CHIP 2023; 23:1531-1546. [PMID: 36723025 PMCID: PMC10013350 DOI: 10.1039/d2lc01045c] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 01/14/2023] [Indexed: 06/18/2023]
Abstract
Upon cutaneous injury, the human body naturally forms an electric field (EF) that acts as a guidance cue for relevant cellular and tissue repair and reorganization. However, the direct current (DC) flow imparted by this EF can be impacted by a variety of diseases. This work delves into the impact of DC stimulation on both healthy and diabetic in vitro wound healing models of human keratinocytes, the most prevalent cell type of the skin. The culmination of non-metal electrode materials and prudent microfluidic design allowed us to create a compact bioelectronic platform to study the effects of different sustained (12 hours galvanostatic DC) EF configurations on wound closure dynamics. Specifically, we compared if electrotactically closing a wound's gap from one wound edge (i.e., uni-directional EF) is as effective as compared to alternatingly polarizing both the wound's edges (i.e., pseudo-converging EF) as both of these spatial stimulation strategies are fundamental to the eventual translational electrode design and strategy. We found that uni-directional electric guidance cues were superior in group keratinocyte healing dynamics by enhancing the wound closure rate nearly three-fold for both healthy and diabetic-like keratinocyte collectives, compared to their non-stimulated respective controls. The motility-inhibited and diabetic-like keratinocytes regained wound closure rates with uni-directional electrical stimulation (increase from 1.0 to 2.8% h-1) comparable to their healthy non-stimulated keratinocyte counterparts (3.5% h-1). Our results bring hope that electrical stimulation delivered in a controlled manner can be a viable pathway to accelerate wound repair, and also by providing a baseline for other researchers trying to find an optimal electrode blueprint for in vivo DC stimulation.
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Affiliation(s)
- Sebastian Shaner
- Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 201, 79110, Freiburg, Germany
- Brainlinks-Braintools Center, Georges-Köhler-Allee 201, 79110, Freiburg, Germany.
| | - Anna Savelyeva
- Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 201, 79110, Freiburg, Germany
- Brainlinks-Braintools Center, Georges-Köhler-Allee 201, 79110, Freiburg, Germany.
| | - Anja Kvartuh
- Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 201, 79110, Freiburg, Germany
| | - Nicole Jedrusik
- Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 201, 79110, Freiburg, Germany
- Brainlinks-Braintools Center, Georges-Köhler-Allee 201, 79110, Freiburg, Germany.
| | - Lukas Matter
- Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 201, 79110, Freiburg, Germany
| | - José Leal
- Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 201, 79110, Freiburg, Germany
- Brainlinks-Braintools Center, Georges-Köhler-Allee 201, 79110, Freiburg, Germany.
| | - Maria Asplund
- Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 201, 79110, Freiburg, Germany
- Brainlinks-Braintools Center, Georges-Köhler-Allee 201, 79110, Freiburg, Germany.
- Freiburg Institute for Advanced Studies (FRIAS), University of Freiburg, Albertstr. 19, 79104, Freiburg, Germany
- Division of Nursing and Medical Technology, Luleå University of Technology, 971 87, Luleå, Sweden
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, Kemivägen 9, 412 58, Gothenburg, Sweden.
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4
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A microfluidic perspective on conventional in vitro transcranial direct current stimulation methods. J Neurosci Methods 2023; 385:109761. [PMID: 36470469 PMCID: PMC9884911 DOI: 10.1016/j.jneumeth.2022.109761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 11/20/2022] [Accepted: 11/30/2022] [Indexed: 12/12/2022]
Abstract
Transcranial direct current stimulation (tDCS) is a promising non-invasive brain stimulation method to treat neurological and psychiatric diseases. However, its underlying neural mechanisms warrant further investigation. Indeed, dose-response interrelations are poorly understood. Placing explanted brain tissue, mostly from mice or rats, into a uniform direct current electric field (dcEF) is a well-established in vitro system to elucidate the neural mechanism of tDCS. Nevertheless, we will show that generating a defined, uniform, and constant dcEF throughout a brain slice is challenging. This article critically reviews the methods used to generate and calibrate a uniform dcEF. We use finite element analysis (FEA) to evaluate the widely used parallel electrode configuration and show that it may not reliably generate uniform dcEF within a brain slice inside an open interface or submerged chamber. Moreover, equivalent circuit analysis and measurements inside a testing chamber suggest that calibrating the dcEF intensity with two recording electrodes can inaccurately capture the true EF magnitude in the targeted tissue when specific criteria are not met. Finally, we outline why microfluidic chambers are an effective and calibration-free approach of generating spatiotemporally uniform dcEF for DCS in vitro studies, facilitating accurate and fine-scale dcEF adjustments. We are convinced that improving the precision and addressing the limitations of current experimental platforms will substantially improve the reproducibility of in vitro experimental results. A better mechanistic understanding of dose-response relations will ultimately facilitate more effective non-invasive stimulation therapies in patients.
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5
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O’Hara-Wright M, Mobini S, Gonzalez-Cordero A. Bioelectric Potential in Next-Generation Organoids: Electrical Stimulation to Enhance 3D Structures of the Central Nervous System. Front Cell Dev Biol 2022; 10:901652. [PMID: 35656553 PMCID: PMC9152151 DOI: 10.3389/fcell.2022.901652] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 05/02/2022] [Indexed: 12/21/2022] Open
Abstract
Pluripotent stem cell-derived organoid models of the central nervous system represent one of the most exciting areas in in vitro tissue engineering. Classically, organoids of the brain, retina and spinal cord have been generated via recapitulation of in vivo developmental cues, including biochemical and biomechanical. However, a lesser studied cue, bioelectricity, has been shown to regulate central nervous system development and function. In particular, electrical stimulation of neural cells has generated some important phenotypes relating to development and differentiation. Emerging techniques in bioengineering and biomaterials utilise electrical stimulation using conductive polymers. However, state-of-the-art pluripotent stem cell technology has not yet merged with this exciting area of bioelectricity. Here, we discuss recent findings in the field of bioelectricity relating to the central nervous system, possible mechanisms, and how electrical stimulation may be utilised as a novel technique to engineer “next-generation” organoids.
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Affiliation(s)
- Michelle O’Hara-Wright
- Stem Cell Medicine Group, Children’s Medical Research Institute, University of Sydney, Westmead, NSW, Australia
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Westmead, NSW, Australia
| | - Sahba Mobini
- Instituto de Micro y Nanotecnología, IMN-CNM, CSIC (CEI UAM + CSIC), Madrid, Spain
| | - Anai Gonzalez-Cordero
- Stem Cell Medicine Group, Children’s Medical Research Institute, University of Sydney, Westmead, NSW, Australia
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Westmead, NSW, Australia
- *Correspondence: Anai Gonzalez-Cordero,
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6
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Zimmermann J, Budde K, Arbeiter N, Molina F, Storch A, Uhrmacher AM, van Rienen U. Using a Digital Twin of an Electrical Stimulation Device to Monitor and Control the Electrical Stimulation of Cells in vitro. Front Bioeng Biotechnol 2021; 9:765516. [PMID: 34957068 PMCID: PMC8693021 DOI: 10.3389/fbioe.2021.765516] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 11/01/2021] [Indexed: 12/12/2022] Open
Abstract
Electrical stimulation for application in tissue engineering and regenerative medicine has received increasing attention in recent years. A variety of stimulation methods, waveforms and amplitudes have been studied. However, a clear choice of optimal stimulation parameters is still not available and is complicated by ambiguous reporting standards. In order to understand underlying cellular mechanisms affected by the electrical stimulation, the knowledge of the actual prevailing field strength or current density is required. Here, we present a comprehensive digital representation, a digital twin, of a basic electrical stimulation device for the electrical stimulation of cells in vitro. The effect of electrochemical processes at the electrode surface was experimentally characterised and integrated into a numerical model of the electrical stimulation. Uncertainty quantification techniques were used to identify the influence of model uncertainties on relevant observables. Different stimulation protocols were compared and it was assessed if the information contained in the monitored stimulation pulses could be related to the stimulation model. We found that our approach permits to model and simulate the recorded rectangular waveforms such that local electric field strengths become accessible. Moreover, we could predict stimulation voltages and currents reliably. This enabled us to define a controlled stimulation setting and to identify significant temperature changes of the cell culture in the monitored voltage data. Eventually, we give an outlook on how the presented methods can be applied in more complex situations such as the stimulation of hydrogels or tissue in vivo.
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Affiliation(s)
- Julius Zimmermann
- Institute of General Electrical Engineering, University of Rostock, Rostock, Germany
| | - Kai Budde
- Institute for Visual and Analytic Computing, University of Rostock, Rostock, Germany
| | - Nils Arbeiter
- Institute of General Electrical Engineering, University of Rostock, Rostock, Germany
| | - Francia Molina
- Department of Neurology, University of Rostock, Rostock, Germany
| | - Alexander Storch
- Department of Neurology, University of Rostock, Rostock, Germany
| | - Adelinde M Uhrmacher
- Institute for Visual and Analytic Computing, University of Rostock, Rostock, Germany.,Department Life, Light and Matter, University of Rostock, Rostock, Germany
| | - Ursula van Rienen
- Institute of General Electrical Engineering, University of Rostock, Rostock, Germany.,Department Life, Light and Matter, University of Rostock, Rostock, Germany.,Department Ageing of Individuals and Society, University of Rostock, Rostock, Germany
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7
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Zajdel TJ, Shim G, Cohen DJ. Come together: On-chip bioelectric wound closure. Biosens Bioelectron 2021; 192:113479. [PMID: 34265520 PMCID: PMC8453109 DOI: 10.1016/j.bios.2021.113479] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 06/16/2021] [Accepted: 06/30/2021] [Indexed: 01/08/2023]
Abstract
There is a growing interest in bioelectric wound treatment and electrotaxis, the process by which cells detect an electric field and orient their migration along its direction, has emerged as a potential cornerstone of the endogenous wound healing response. Despite recognition of the importance of electrotaxis in wound healing, no experimental demonstration to date has shown that the actual closing of a wound can be accelerated solely by the electrotaxis response itself, and in vivo systems are too complex to resolve cell migration from other healing stages such as proliferation and inflammation. This uncertainty has led to a lack of standardization between stimulation methods, model systems, and electrode technology required for device development. In this paper, we present a 'healing-on-chip' approach that is a standardized, low-cost, model for investigating electrically accelerated wound healing. Our device provides a biomimetic convergent field geometry that more closely resembles actual wound fields. We validate this device by using electrical stimulation to close a 1.5 mm gap between two large (30 mm2) layers of primary skin keratinocyte to completely heal the gap twice as quickly as in an unstimulated tissue. This demonstration proves that convergent electrotaxis is both possible and can accelerate healing and offers an accessible 'healing-on-a-chip' platform to explore future bioelectric interfaces.
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Affiliation(s)
- Tom J Zajdel
- Mechanical & Aerospace Engineering, Princeton University, 08544, Princeton, NJ, United States
| | - Gawoon Shim
- Mechanical & Aerospace Engineering, Princeton University, 08544, Princeton, NJ, United States
| | - Daniel J Cohen
- Mechanical & Aerospace Engineering, Princeton University, 08544, Princeton, NJ, United States.
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8
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Gellner AK, Reis J, Fiebich BL, Fritsch B. Electrified microglia: Impact of direct current stimulation on diverse properties of the most versatile brain cell. Brain Stimul 2021; 14:1248-1258. [PMID: 34411753 DOI: 10.1016/j.brs.2021.08.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 08/07/2021] [Accepted: 08/09/2021] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Transcranial direct current stimulation [(t)DCS], modulates cortical excitability and promotes neuroplasticity. Microglia has been identified to respond to electrical currents as well as neuronal activity, but its response to DCS is mostly unknown. OBJECTIVE This study addresses effects of DCS applied in vivo to the sensorimotor cortex on physiological microglia properties and neuron-microglia communication. METHODS Time lapse in vivo 2-photon microscopy in anaesthetized mice was timely coupled with DCS of the sensorimotor cortex to observe microglia dynamics on a population-based and single cell level. Neuron-microglia communication during DCS was investigated in mice with a functional knock out of the fractalkine receptor CX3CR1. Moreover, the role of voltage gated microglial channels and DCS effects on phagocytosis were studied. RESULTS DCS promoted several physiological microglia properties, depending on the glial activation state and stimulation intensity. On a single cell level, process motility was predominantly enhanced in ramified cells whereas horizontal soma movement and galvanotaxis was pronounced in reactive microglia. Blockage of voltage sensitive microglial channels suppressed DCS effects in vivo and in vitro. Microglial motility changes were partially driven by the fractalkine signaling pathway. Moreover, phagocytosis increased after DCS in vitro. CONCLUSION Microglia dynamics are rapidly influenced by DCS. This is the first in vivo demonstration of a direct effect of electrical currents on microglia and indirect effects potentially driven by neuronal activity via the fractalkine pathway.
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Affiliation(s)
- Anne-Kathrin Gellner
- Department of Neurology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Breisacher Str. 64, 79106, Freiburg, Germany; Department of Psychiatry and Psychotherapy, University Hospital Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Janine Reis
- Department of Neurology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Breisacher Str. 64, 79106, Freiburg, Germany
| | - Bernd L Fiebich
- Neurochemistry and Neuroimmunology Research Group, Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Hauptstrasse 5, 79104, Freiburg, Germany
| | - Brita Fritsch
- Department of Neurology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Breisacher Str. 64, 79106, Freiburg, Germany.
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9
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SIROF stabilized PEDOT/PSS allows biocompatible and reversible direct current stimulation capable of driving electrotaxis in cells. Biomaterials 2021; 275:120949. [PMID: 34153784 DOI: 10.1016/j.biomaterials.2021.120949] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 05/18/2021] [Accepted: 05/30/2021] [Indexed: 12/30/2022]
Abstract
Electrotaxis is a naturally occurring phenomenon in which ionic gradients dictate the directed migration of cells involved in different biological processes such as wound healing, embryonic development, or cancer metastasis. To investigate these processes, direct current (DC) has been used to generate electric fields capable of eliciting an electrotactic response in cells. However, the need for metallic electrodes to deliver said currents has hindered electrotaxis research and the application of DC stimulation as medical therapy. This study aimed to investigate the capability of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT/PSS) on sputtered iridium oxide film (SIROF) electrodes to generate stable direct currents. The electrochemical properties of PEDOT/PSS allow ions to be released and reabsorbed depending on the polarity of the current flow. SIROF stabilized PEDOT/PSS electrodes demonstrated exceptional stability in voltage and current controlled DC stimulation for periods of up to 12 hours. These electrodes were capable of directing cell migration of the rat prostate cancer cell line MAT-LyLu in a microfluidic chamber without the need for chemical buffers. This material combination shows excellent promise for accelerating electrotaxis research and facilitating the translation of DC stimulation to medical applications thanks to its biocompatibility, ionic charge injection mechanisms, and recharging capabilities in a biological environment.
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10
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Ryan CNM, Doulgkeroglou MN, Zeugolis DI. Electric field stimulation for tissue engineering applications. BMC Biomed Eng 2021; 3:1. [PMID: 33397515 PMCID: PMC7784019 DOI: 10.1186/s42490-020-00046-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 12/06/2020] [Indexed: 01/02/2023] Open
Abstract
Electric fields are involved in numerous physiological processes, including directional embryonic development and wound healing following injury. To study these processes in vitro and/or to harness electric field stimulation as a biophysical environmental cue for organised tissue engineering strategies various electric field stimulation systems have been developed. These systems are overall similar in design and have been shown to influence morphology, orientation, migration and phenotype of several different cell types. This review discusses different electric field stimulation setups and their effect on cell response.
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Affiliation(s)
- Christina N M Ryan
- Regenerative, Modular & Developmental Engineering Laboratory (REMODEL), National University of Ireland Galway & USI, Galway, Ireland.,Science Foundation Ireland (SFI) Centre for Research in Medical Devices (CÚRAM), National University of Ireland Galway, Galway, Ireland
| | - Meletios N Doulgkeroglou
- Regenerative, Modular & Developmental Engineering Laboratory (REMODEL), National University of Ireland Galway & USI, Galway, Ireland.,Science Foundation Ireland (SFI) Centre for Research in Medical Devices (CÚRAM), National University of Ireland Galway, Galway, Ireland
| | - Dimitrios I Zeugolis
- Regenerative, Modular & Developmental Engineering Laboratory (REMODEL), National University of Ireland Galway & USI, Galway, Ireland. .,Science Foundation Ireland (SFI) Centre for Research in Medical Devices (CÚRAM), National University of Ireland Galway, Galway, Ireland. .,Regenerative, Modular & Developmental Engineering Laboratory (REMODEL), Faculty of Biomedical Sciences, Università della Svizzera Italiana (USI), Lugano, Switzerland.
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11
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Guette-Marquet S, Roques C, Bergel A. Theoretical analysis of the electrochemical systems used for the application of direct current/voltage stimuli on cell cultures. Bioelectrochemistry 2021; 139:107737. [PMID: 33494030 DOI: 10.1016/j.bioelechem.2020.107737] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 12/22/2020] [Accepted: 12/29/2020] [Indexed: 12/31/2022]
Abstract
Endogenous electric fields drive many essential functions relating to cell proliferation, motion, differentiation and tissue development. They are usually mimicked in vitro by using electrochemical systems to apply direct current or voltage stimuli to cell cultures. The many studies devoted to this topic have given rise to a wide variety of experimental systems, whose results are often difficult to compare. Here, these systems are analysed from an electrochemical standpoint to help harmonize protocols and facilitate optimal understanding of the data produced. The theoretical analysis of single-electrode systems shows the necessity of measuring the Nernst potential of the electrode and of discussing the results on this basis rather than using the value of the potential gradient. The paper then emphasizes the great complexity that can arise when high cell voltage is applied to a single electrode, because of the possible occurrence of anode and cathode sites. An analysis of two-electrode systems leads to the advice to change experimental practices by applying current instead of voltage. It also suggests that the values of electric fields reported so far may have been considerably overestimated in macro-sized devices. It would consequently be wise to revisit this area by testing considerably lower electric field values.
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Affiliation(s)
- Simon Guette-Marquet
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - Christine Roques
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - Alain Bergel
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France.
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12
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Zimmermann J, Distler T, Boccaccini AR, van Rienen U. Numerical Simulations as Means for Tailoring Electrically Conductive Hydrogels Towards Cartilage Tissue Engineering by Electrical Stimulation. Molecules 2020; 25:E4750. [PMID: 33081205 PMCID: PMC7587583 DOI: 10.3390/molecules25204750] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 09/11/2020] [Accepted: 10/06/2020] [Indexed: 12/12/2022] Open
Abstract
Cartilage regeneration is a clinical challenge. In recent years, hydrogels have emerged as implantable scaffolds in cartilage tissue engineering. Similarly, electrical stimulation has been employed to improve matrix synthesis of cartilage cells, and thus to foster engineering and regeneration of cartilage tissue. The combination of hydrogels and electrical stimulation may pave the way for new clinical treatment of cartilage lesions. To find the optimal electric properties of hydrogels, theoretical considerations and corresponding numerical simulations are needed to identify well-suited initial parameters for experimental studies. We present the theoretical analysis of a hydrogel in a frequently used electrical stimulation device for cartilage regeneration and tissue engineering. By means of equivalent circuits, finite element analysis, and uncertainty quantification, we elucidate the influence of the geometric and dielectric properties of cell-seeded hydrogels on the capacitive-coupling electrical field stimulation. Moreover, we discuss the possibility of cellular organisation inside the hydrogel due to forces generated by the external electric field. The introduced methodology is easily reusable by other researchers and allows to directly develop novel electrical stimulation study designs. Thus, this study paves the way for the design of future experimental studies using electrically conductive hydrogels and electrical stimulation for tissue engineering.
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Affiliation(s)
- Julius Zimmermann
- Institute of General Electrical Engineering, University of Rostock, 18051 Rostock, Germany;
| | - Thomas Distler
- Institute of Biomaterials, Friedrich Alexander University Erlangen-Nuremberg, 91058 Erlangen, Germany; (T.D.); (A.R.B.)
| | - Aldo R. Boccaccini
- Institute of Biomaterials, Friedrich Alexander University Erlangen-Nuremberg, 91058 Erlangen, Germany; (T.D.); (A.R.B.)
| | - Ursula van Rienen
- Institute of General Electrical Engineering, University of Rostock, 18051 Rostock, Germany;
- Department Life, Light & Matter, University of Rostock, 18051 Rostock, Germany
- Department of Ageing of Individuals and Society, Interdisciplinary Faculty, University of Rostock, 18051 Rostock, Germany
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Zajdel TJ, Shim G, Wang L, Rossello-Martinez A, Cohen DJ. SCHEEPDOG: Programming Electric Cues to Dynamically Herd Large-Scale Cell Migration. Cell Syst 2020; 10:506-514.e3. [PMID: 32684277 PMCID: PMC7779114 DOI: 10.1016/j.cels.2020.05.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 05/06/2020] [Accepted: 05/19/2020] [Indexed: 10/24/2022]
Abstract
Directed cell migration is critical across biological processes spanning healing to cancer invasion, yet no existing tools allow real-time interactive guidance over such migration. We present a new bioreactor that harnesses electrotaxis-directed cell migration along electric field gradients-by integrating four independent electrodes under computer control to dynamically program electric field patterns, and hence steer cell migration. Using this platform, we programmed and characterized multiple precise, two-dimensional collective migration maneuvers in renal epithelia and primary skin keratinocyte ensembles. First, we demonstrated on-demand, 90-degree collective turning. Next, we developed a universal electrical stimulation scheme capable of programming arbitrary 2D migration maneuvers such as precise angular turns and migration in a complete circle. Our stimulation scheme proves that cells effectively time-average electric field cues, helping to elucidate the transduction timescales in electrotaxis. Together, this work represents an enabling platform for controlling cell migration with broad utility across many cell types.
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Affiliation(s)
- Tom J Zajdel
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Gawoon Shim
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Linus Wang
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Alejandro Rossello-Martinez
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA; Department of Aeronautics, Imperial College London, London SW7 2AZ, UK
| | - Daniel J Cohen
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA.
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Abstract
As the leading cause of death in cancer, there is an urgent need to develop treatments to target the dissemination of primary tumor cells to secondary organs, known as metastasis. Bioelectric signaling has emerged in the last century as an important controller of cell growth, and with the development of current molecular tools we are now beginning to identify its role in driving cell migration and metastasis in a variety of cancer types. This review summarizes the currently available research for bioelectric signaling in solid tumor metastasis. We review the steps of metastasis and discuss how these can be controlled by bioelectric cues at the level of a cell, a population of cells, and the tissue. The role of ion channel, pump, and exchanger activity and ion flux is discussed, along with the importance of the membrane potential and the relationship between ion flux and membrane potential. We also provide an overview of the evidence for control of metastasis by external electric fields (EFs) and draw from examples in embryogenesis and regeneration to discuss the implications for endogenous EFs. By increasing our understanding of the dynamic properties of bioelectric signaling, we can develop new strategies that target metastasis to be translated into the clinic.
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Affiliation(s)
- Samantha L. Payne
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts
| | - Michael Levin
- Allen Discovery Center, Tufts University, Medford, Massachusetts
| | - Madeleine J. Oudin
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts
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