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Payonk JP, Bathel H, Arbeiter N, Kober M, Fauser M, Storch A, van Rienen U, Zimmermann J. Improving computational models of deep brain stimulation through experimental calibration. J Neurosci Methods 2025; 414:110320. [PMID: 39549963 DOI: 10.1016/j.jneumeth.2024.110320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2024] [Revised: 10/20/2024] [Accepted: 11/06/2024] [Indexed: 11/18/2024]
Abstract
BACKGROUND Deep brain stimulation has become a well-established clinical tool to treat movement disorders. Nevertheless, the knowledge of processes initiated by the stimulation remains limited. To address this knowledge gap, computational models are developed to gain deeper insight. However, their predictive power remains constrained by model uncertainties and a lack of validation and calibration. NEW METHOD Exemplified with rodent microelectrodes, we present a workflow for validating electrode model geometry using microscopy and impedance spectroscopy in vitro before implantation. We address uncertainties in the tissue distribution and dielectric properties and outline a concept for calibrating the computational model based on in vivo impedance spectroscopy measurements. RESULTS The standard deviation of the volume of tissue activated across the 18 characterized electrodes was approximately 32.93%, underscoring the importance of electrode characterization. Thus, the workflow significantly enhances the model predictions' credibility of neural activation exemplified in a rodent model. COMPARISON WITH EXISTING METHODS Computational models are frequently employed without validation or calibration, relying instead on manufacturers' specifications. Our approach provides an accessible method to obtain a validated and calibrated electrode geometry, which significantly enhances the reliability of the computational model that relies on this electrode. CONCLUSION By reducing the uncertainties of the model, the accuracy in predicting neural activation is increased. The entire workflow is realized in open-source software, making it adaptable for other use cases, such as deep brain stimulation in humans. Additionally, the framework allows for the integration of further experiments, enabling live updates and refinements to computational models.
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Affiliation(s)
- Jan Philipp Payonk
- Institute of General Electrical Engineering, University of Rostock, Albert-Einstein-Straße 2, Rostock, 18051, Germany.
| | - Henning Bathel
- Institute of General Electrical Engineering, University of Rostock, Albert-Einstein-Straße 2, Rostock, 18051, Germany
| | - Nils Arbeiter
- Institute of General Electrical Engineering, University of Rostock, Albert-Einstein-Straße 2, Rostock, 18051, Germany
| | - Maria Kober
- Department of Neurology, University of Rostock, Gehlsheimer Straße 20, Rostock, 18147, Germany
| | - Mareike Fauser
- Department of Neurology, University of Rostock, Gehlsheimer Straße 20, Rostock, 18147, Germany
| | - Alexander Storch
- Department of Neurology, University of Rostock, Gehlsheimer Straße 20, Rostock, 18147, Germany; German Centre for Neurodegenerative Diseases (DZNE) Rostock-Greifswald, Gehlsheimer Straße 20, Rostock, 18147, Germany
| | - Ursula van Rienen
- Institute of General Electrical Engineering, University of Rostock, Albert-Einstein-Straße 2, Rostock, 18051, Germany; Department Life, Light & Matter, University of Rostock, Albert-Einstein-Straße 25, Rostock, 18051, Germany; Department of Ageing of Individuals and Society, University of Rostock, Albert-Einstein-Straße 21, Rostock, 18051, Germany.
| | - Julius Zimmermann
- Institute of General Electrical Engineering, University of Rostock, Albert-Einstein-Straße 2, Rostock, 18051, Germany
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Zimmermann J, Farooqi AR, van Rienen U. Electrical stimulation for cartilage tissue engineering - A critical review from an engineer's perspective. Heliyon 2024; 10:e38112. [PMID: 39416819 PMCID: PMC11481755 DOI: 10.1016/j.heliyon.2024.e38112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Revised: 08/31/2024] [Accepted: 09/18/2024] [Indexed: 10/19/2024] Open
Abstract
Cartilage has a limited intrinsic healing capacity. Hence, cartilage degradation and lesions pose a huge clinical challenge, particularly in an ageing society. Osteoarthritis impacts a significant number of the population and requires the development of repair and tissue engineering methods for hyaline articular cartilage. In this context, electrical stimulation has been investigated for more than 50 years already. Yet, no well-established clinical therapy to treat osteoarthritis by means of electrical stimulation exists. We argue that one reason is the lack of replicability of electrical stimulation devices from a technical perspective together with lacking hypotheses of the biophysical mechanism. Hence, first, the electrical stimulation studies reported in the context of cartilage tissue engineering with a special focus on technical details are summarized. Then, an experimental and numerical approach is discussed to make the electrical stimulation experiments replicable. Finally, biophysical hypotheses have been reviewed on the interaction of electric fields and cells that are relevant for cartilage tissue engineering. With that, the aim is to inspire future research to enable clinical electrical stimulation therapies to fight osteoarthritis.
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Affiliation(s)
- Julius Zimmermann
- Institute of General Electrical Engineering, University of Rostock, 18051 Rostock, Germany
| | - Abdul Razzaq Farooqi
- Institute of General Electrical Engineering, University of Rostock, 18051 Rostock, Germany
- Department of Electronic Engineering, Faculty of Engineering, The Islamia University of Bahawalpur, 63100 Bahawalpur, Pakistan
| | - Ursula van Rienen
- Institute of General Electrical Engineering, University of Rostock, 18051 Rostock, Germany
- Department of Ageing of Individuals and Society, Interdisciplinary Faculty, University of Rostock, 18051 Rostock, Germany
- Department Life, Light & Matter, University of Rostock, 18051 Rostock, Germany
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Raben H, Kammerer PW, van Rienen U. Addressing Model Uncertainties in Finite Element Simulation of Electrically Stimulated Implants for Critical-Size Mandibular Defects. IEEE Trans Biomed Eng 2024; 71:3055-3068. [PMID: 38819969 DOI: 10.1109/tbme.2024.3408076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2024]
Abstract
OBJECTIVE Electrical stimulation is known to enhance bone healing. Novel electrostimulating devices are currently being developed for the treatment of critical-size bone defects in the mandible. Previous numerical models of these devices did not account for possible uncertainties in the input data. We present the numerical model of an electrically stimulated minipig mandible, including optimization and uncertainty quantification (UQ) methods that allow us to determine the most influential parameters. METHODS Uncertainties in the optimized finite element model are quantified using the polynomial chaos method that is implemented in the open-source Python toolbox Uncertainpy. The volumes of understimulated, beneficially stimulated, and overstimulated tissue are considered quantities of interest because they may significantly impact the expected healing success. Further, the current is a substantial quantity, limiting the lifetime of a battery-driven stimulation unit. With sensitivity analyses, the most critical parameters in the numerical model can be identified. Thus, we can learn which parameters are particularly relevant, for example, when conceptualizing the stimulation unit or planning the manufacturing process. RESULTS The results of this study show that the parameters of the electrode-tissue interface (ETI), as well as the conductivity within the defect volume, have the most significant impact on the model results. CONCLUSIONS The UQ results suggest that careful characterization of the ETI and the dielectric tissue properties is crucial to reduce these uncertainties. SIGNIFICANCE The numerical model regarding uncertainties yields important implications for reliable implant design and clinical translation.
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Opančar A, Głowacki ED, Đerek V. Choosing the right electrode representation for modeling real bioelectronic interfaces: a comprehensive guide. J Neural Eng 2024; 21:046049. [PMID: 39094614 DOI: 10.1088/1741-2552/ad6a8b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 08/01/2024] [Indexed: 08/04/2024]
Abstract
Objective.Producing realistic numerical models of neurostimulation electrodes in contact with the electrolyte and tissue, for use in time-domain finite element method simulations while maintaining a reasonable computational burden remains a challenge. We aim to provide a straightforward experimental-theoretical hybrid approach for common electrode materials (Ti, TiN, ITO, Au, Pt, IrOx) that are relevant to the research field of bioelectronics, along with all the information necessary to replicate our approach in arbitrary geometry for real-life experimental applications.Approach.We used electrochemical impedance spectroscopy (EIS) to extract the electrode parameters in the AC regime under different DC biases. The pulsed electrode response was obtained by fast amperometry (FA) to optimize and verify the previously obtained electrode parameters in a COMSOL Multiphysics model. For optimization of the electrode parameters a constant phase element (CPE) needed to be implemented in time-domain.Main results.We find that the parameters obtained by EIS can be used to accurately simulate pulsed response only close to the electrode open circuit potential, while at other potentials we give corrections to the obtained parameters, based on FA measurements. We also find that for many electrodes (Au, TiN, Pt, and IrOx), it is important to implement a distributed CPE rather than an ideal capacitor for estimating the electrode double-layer capacitance. We outline and provide examples for the novel time-domain implementation of the CPE for finite element method simulations in COMSOL Multiphysics.Significance.An overview of electrode parameters for some common electrode materials can be a valuable and useful tool in numerical bioelectronics models. A provided FEM implementation model can be readily adapted to arbitrary electrode geometries and used for various applications. Finally, the presented methodology for parametrization of electrode materials can be used for any materials of interest which were not covered by this work.
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Affiliation(s)
- Aleksandar Opančar
- Department of Physics, Faculty of Science, University of Zagreb, Bijenička c. 32, 10000 Zagreb, Croatia
- Bioelectronics Materials and Devices Laboratory, Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 61200 Brno, Czech Republic
| | - Eric Daniel Głowacki
- Bioelectronics Materials and Devices Laboratory, Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 61200 Brno, Czech Republic
| | - Vedran Đerek
- Department of Physics, Faculty of Science, University of Zagreb, Bijenička c. 32, 10000 Zagreb, Croatia
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Silva JC, Meneses J, Garrudo FFF, Fernandes SR, Alves N, Ferreira FC, Pascoal-Faria P. Direct coupled electrical stimulation towards improved osteogenic differentiation of human mesenchymal stem/stromal cells: a comparative study of different protocols. Sci Rep 2024; 14:5458. [PMID: 38443455 PMCID: PMC10915174 DOI: 10.1038/s41598-024-55234-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 02/21/2024] [Indexed: 03/07/2024] Open
Abstract
Electrical stimulation (ES) has been described as a promising tool for bone tissue engineering, being known to promote vital cellular processes such as cell proliferation, migration, and differentiation. Despite the high variability of applied protocol parameters, direct coupled electric fields have been successfully applied to promote osteogenic and osteoinductive processes in vitro and in vivo. Our work aims to study the viability, proliferation, and osteogenic differentiation of human bone marrow-derived mesenchymal stem/stromal cells when subjected to five different ES protocols. The protocols were specifically selected to understand the biological effects of different parts of the generated waveform for typical direct-coupled stimuli. In vitro culture studies evidenced variations in cell responses with different electric field magnitudes (numerically predicted) and exposure protocols, mainly regarding tissue mineralization (calcium contents) and osteogenic marker gene expression while maintaining high cell viability and regular morphology. Overall, our results highlight the importance of numerical guided experiments to optimize ES parameters towards improved in vitro osteogenesis protocols.
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Affiliation(s)
- João C Silva
- Department of Bioengineering and iBB-Institute of Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001, Lisboa, Portugal.
- Associate Laboratory i4HB-Institute for Health and Bioeconomy, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001, Lisboa, Portugal.
- Centre for Rapid and Sustainable Product Development (CDRSP), Polytechnic of Leiria, Marinha Grande, 2430-028, Leiria, Portugal.
| | - João Meneses
- Centre for Rapid and Sustainable Product Development (CDRSP), Polytechnic of Leiria, Marinha Grande, 2430-028, Leiria, Portugal.
- Instituto de Biofísica e Engenharia Biomédica, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016, Lisboa, Portugal.
| | - Fábio F F Garrudo
- Department of Bioengineering and iBB-Institute of Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001, Lisboa, Portugal
- Associate Laboratory i4HB-Institute for Health and Bioeconomy, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001, Lisboa, Portugal
- Instituto de Telecomunicações, Instituto Superior Técnico, Universidade de Lisboa, Avenida Rovisco Pais, 1049-001, Lisboa, Portugal
| | - Sofia R Fernandes
- Instituto de Biofísica e Engenharia Biomédica, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016, Lisboa, Portugal
| | - Nuno Alves
- Centre for Rapid and Sustainable Product Development (CDRSP), Polytechnic of Leiria, Marinha Grande, 2430-028, Leiria, Portugal
- Associate Laboratory for Advanced Production and Intelligent Systems (ARISE), 4050-313, Porto, Portugal
- Department of Mechanical Engineering, School of Technology and Management, Polytechnic of Leiria, Morro do Lena-Alto do Vieiro, Apartado 4163, 2411-901, Leiria, Portugal
| | - Frederico Castelo Ferreira
- Department of Bioengineering and iBB-Institute of Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001, Lisboa, Portugal
- Associate Laboratory i4HB-Institute for Health and Bioeconomy, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001, Lisboa, Portugal
| | - Paula Pascoal-Faria
- Centre for Rapid and Sustainable Product Development (CDRSP), Polytechnic of Leiria, Marinha Grande, 2430-028, Leiria, Portugal.
- Associate Laboratory for Advanced Production and Intelligent Systems (ARISE), 4050-313, Porto, Portugal.
- Department of Mathematics, School of Technology and Management, Polytechnic of Leiria, Morro do Lena - Alto do Vieiro, Apartado 4163, 2411-901, Leiria, Portugal.
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Uzieliene I, Popov A, Vaiciuleviciute R, Kirdaite G, Bernotiene E, Ramanaviciene A. Polypyrrole-based structures for activation of cellular functions under electrical stimulation. Bioelectrochemistry 2024; 155:108585. [PMID: 37847982 DOI: 10.1016/j.bioelechem.2023.108585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 10/04/2023] [Accepted: 10/08/2023] [Indexed: 10/19/2023]
Abstract
Polypyrrole (Ppy) is an electroconductive polymer used in various applications, including in vitro experiments with cell cultures under electrical stimulation (ES). Ppy can be applied in various forms and most importantly, it is biocompatible with cells. Ppy specifically directs ES to cells, which makes Ppy a potential polymer for the development of novel technologies for targeted tissue regeneration. The high potential of ES in combination with different Ppy-based systems, such as hydrogels, scaffolds, or Ppy-layers is advantageous to stimulate cellular differentiation towards neurogenic, cardiac, muscle, and osteogenic lineages. Different in-house devices and the principles of ES application used to stimulate cellular functions are reviewed and summarized. The focus of this review is to observe the most relevant studies and their in-house techniques regarding the application of Ppy-based materials for the use of bone, neural, cardiac, and muscle tissue regeneration under ES. Different types of Ppy materials, such as Ppy particles, layers/films, membranes, and 3D-shaped synthetic and natural scaffolds, as well as combining Ppy with different active molecules are reviewed.
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Affiliation(s)
- Ilona Uzieliene
- Department of Regenerative Medicine, State Research Institute Centre for Innovative Medicine, LT-08406 Vilnius, Lithuania; Department of Immunology, State Research Institute Centre for Innovative Medicine, LT-08406 Vilnius, Lithuania
| | - Anton Popov
- Department of Immunology, State Research Institute Centre for Innovative Medicine, LT-08406 Vilnius, Lithuania; NanoTechnas - Center on Nanotechnology and Materials Sciences, Faculty of Chemistry and Geosciences, Vilnius University, Naugarduko g. 24, LT-03225 Vilnius, Lithuania
| | - Raminta Vaiciuleviciute
- Department of Regenerative Medicine, State Research Institute Centre for Innovative Medicine, LT-08406 Vilnius, Lithuania
| | - Gailute Kirdaite
- Department of Experimental, Preventive and Clinical Medicine, State Research Institute Centre for Innovative Medicine, LT-08406 Vilnius, Lithuania
| | - Eiva Bernotiene
- Department of Regenerative Medicine, State Research Institute Centre for Innovative Medicine, LT-08406 Vilnius, Lithuania; Faculty of Fundamental Sciences, Vilnius Gediminas Technical University, VilniusTech, Sauletekio al. 11, LT-10223 Vilnius, Lithuania
| | - Almira Ramanaviciene
- Department of Immunology, State Research Institute Centre for Innovative Medicine, LT-08406 Vilnius, Lithuania; NanoTechnas - Center on Nanotechnology and Materials Sciences, Faculty of Chemistry and Geosciences, Vilnius University, Naugarduko g. 24, LT-03225 Vilnius, Lithuania.
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Boulingre M, Portillo-Lara R, Green RA. Biohybrid neural interfaces: improving the biological integration of neural implants. Chem Commun (Camb) 2023; 59:14745-14758. [PMID: 37991846 PMCID: PMC10720954 DOI: 10.1039/d3cc05006h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 11/10/2023] [Indexed: 11/24/2023]
Abstract
Implantable neural interfaces (NIs) have emerged in the clinic as outstanding tools for the management of a variety of neurological conditions caused by trauma or disease. However, the foreign body reaction triggered upon implantation remains one of the major challenges hindering the safety and longevity of NIs. The integration of tools and principles from biomaterial design and tissue engineering has been investigated as a promising strategy to develop NIs with enhanced functionality and performance. In this Feature Article, we highlight the main bioengineering approaches for the development of biohybrid NIs with an emphasis on relevant device design criteria. Technical and scientific challenges associated with the fabrication and functional assessment of technologies composed of both artificial and biological components are discussed. Lastly, we provide future perspectives related to engineering, regulatory, and neuroethical challenges to be addressed towards the realisation of the promise of biohybrid neurotechnology.
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Affiliation(s)
- Marjolaine Boulingre
- Department of Bioengineering, Imperial College London, South Kensington, London, SW7 2AZ, UK
| | - Roberto Portillo-Lara
- Department of Bioengineering, Imperial College London, South Kensington, London, SW7 2AZ, UK
| | - Rylie A Green
- Department of Bioengineering, Imperial College London, South Kensington, London, SW7 2AZ, UK
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