Electro-Quasistatic Simulations in Bio-Systems Engineering and Medical Engineering

Rienen, Ursula van; Flehr, Jürgen; Schreiber, U.; Schulze, Sabine; Gimsa, Ulrike; Baumann, Werner; Weiss, Dieter G.; Gimsa, Jan; Pau, H. W.

doi:10.5194/ars-3-39-2005

Cited by 27 publications

(14 citation statements)

References 15 publications

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“…with the imaginary unit j, the angular frequency ω, the permittivity of free space ε 0 , the relative permittivity ε r (r, ω), and the electric conductivity σ(r, ω). Details on the derivation can be retraced in, e.g., [58][59][60].…”

Section: Electro-quasistatic Boundary Value Problemmentioning

confidence: 99%

Establishment of a Numerical Model to Design an Electro-Stimulating System for a Porcine Mandibular Critical Size Defect

Raben

Kämmerer²,

Bader

et al. 2019

Applied Sciences

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Electrical stimulation is a promising therapeutic approach for the regeneration of large bone defects. Innovative electrically stimulating implants for critical size defects in the lower jaw are under development and need to be optimized in silico and tested in vivo prior to application. In this context, numerical modelling and simulation are useful tools in the design process. In this study, a numerical model of an electrically stimulated minipig mandible was established to find optimal stimulation parameters that allow for a maximum area of beneficially stimulated tissue. Finite-element simulations were performed to determine the stimulation impact of the proposed implant design and to optimize the electric field distribution resulting from sinusoidal low-frequency ( f = 20 Hz ) electric stimulation. Optimal stimulation parameters of the electrode length h el = 25 m m and the stimulation potential φ stim = 0.5 V were determined. These parameter sets shall be applied in future in vivo validation studies. Furthermore, our results suggest that changing tissue properties during the course of the healing process might make a feedback-controlled stimulation system necessary.

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Section: Electro-quasistatic Boundary Value Problemmentioning

confidence: 99%

Establishment of a Numerical Model to Design an Electro-Stimulating System for a Porcine Mandibular Critical Size Defect

Raben

Kämmerer²,

Bader

et al. 2019

Applied Sciences

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show abstract

“…We chose frequencies between

Hz and

MHz since they could be covered by commercially available impedance analysers [ 79 ]. Moreover, in this frequency range wave effects, which we neglected in our analysis, are not to be expected [ 80 ].…”

Section: Methodsmentioning

confidence: 99%

“…We chose a modelling approach that is in detail described elsewhere [ 81 ]. Briefly, we solved the electro-quasistatic representation of Maxwell’s equations [ 80 ] by COMSOL Multiphysics ® , V5.3a employing second-order Lagrange elements and a direct solver.…”

Section: Methodsmentioning

confidence: 99%

Numerical Simulations as Means for Tailoring Electrically Conductive Hydrogels towards Cartilage Tissue Engineering by Electrical Stimulation

et al. 2020

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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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“…These time-dependent equations can be simplified under certain circumstances. In many therapeutic approaches for biological systems, slowly varying electromagnetic fields can be assumed [26]. In the so called electroquasistatic regime [27], the electric fields are curl-free and often time-harmonic.…”

Section: Methods and Numerical Modelmentioning

confidence: 99%

Effect of electrical stimulation on biological cells by capacitive coupling – an efficient numerical study considering model uncertainties

Zimmermann¹,

Altenkirch²,

Rienen³

2020

Preprint

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Electrical stimulation of biological samples such as tissues and cell cultures attracts growing attention due to its capability of enhancing cell activity, proliferation and differentiation. Eventually, profound knowledge of the underlying mechanisms paves the way for innovative therapeutic devices. Capacitive coupling is one option of delivering electric fields to biological samples and has advantages with regard to biocompatibility. However, the mechanism of interaction is not well understood. Experimental findings could be related to voltage-gated channels, which are triggered by changes of the transmembrane potential (TMP). Numerical simulations by the Finite Element method (FEM) provide a possibility to estimate the TMP. For realistic simulations of in vitro electric stimulation experiments, a bridge from the mesoscopic level down to the cellular level has to be found. A special challenge poses the ratio between the cell membrane (a few nm) and the general setup (some cm). Hence, a full discretization of the cell membrane becomes prohibitively expensive for 3D simulations. We suggest using an approximate FE method that makes 3D multi-scale simulations possible. Starting from an established 2D model, the chosen method is characterized and applied to realistic in vitro situations. A to date not investigated parameter dependency is included and tackled by means of Uncertainty Quantification (UQ) techniques. It reveals a strong, frequency-dependent influence of uncertain parameters on the modeling result.

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Electro-Quasistatic Simulations in Bio-Systems Engineering and Medical Engineering

Cited by 27 publications

References 15 publications

Establishment of a Numerical Model to Design an Electro-Stimulating System for a Porcine Mandibular Critical Size Defect

Establishment of a Numerical Model to Design an Electro-Stimulating System for a Porcine Mandibular Critical Size Defect

Numerical Simulations as Means for Tailoring Electrically Conductive Hydrogels towards Cartilage Tissue Engineering by Electrical Stimulation

Effect of electrical stimulation on biological cells by capacitive coupling – an efficient numerical study considering model uncertainties

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