Numerical Simulation of Electroactive Hydrogels for Cartilage-Tissue Engineering

Abstract

The intrinsic regeneration potential of hyaline cartilage is highly limited due to the absence of blood vessels, lymphatics, and nerves, as well as a low cell turnover within the tissue. Despite various advancements in the field of regenerative medicine, it remains a challenge to remedy articular cartilage defects resulting from trauma, aging, or osteoarthritis. Among various approaches, tissue engineering using tailored electroactive scaffolds has evolved as a promising strategy to repair damaged cartilage tissue. In this approach, hydrogel scaffolds are used as artificial extracellular matrices, and electric stimulation is applied to facilitate proliferation, differentiation, and cell growth at the defect site. In this regard, we present a simulation model of electroactive hydrogels to be used for cartilage-tissue engineering employing open-source finite-element software FEniCS together with a Python interface. The proposed mathematical formulation was first validated with an example from the literature. Then, we computed the effect of electric stimulation on a circular hydrogel sample that served as a model for a cartilage-repair implant.

Keywords: articular cartilage; cartilage–tissue engineering; computational modelling; electrical stimulation; electrically conductive hydrogels; scaffold.

Figure 1

Various steps involved in tissue engineering of knee articular cartilage using electrical stimulation by replacing defect site with chondrocyte-seeded hydrogel (adapted from [11]).

Figure 2

Hydrogel sample immersed in NaCl bath solution under externally applied electric field.

Figure 3

Proposed open-source simulation workflow.

Figure 4

Cation concentration: (a) 2D electrical stimulation, (b) comparison of chemical and electrical stimulation versus x-position at y = $0.0075$ m.

Figure 5

Anion concentration: (a) 2D electrical stimulation, (b) comparison of chemical and electrical stimulation versus x-position at y = $0.0075$ m.

Figure 6

Electric potential: (a) 2D electrical stimulation, (b) comparison of chemical and electrical stimulation versus x-position at y = $0.0075$ m.

Figure 7

Cation-concentration profile for a hydrogel scaffold immersed in solution.

Figure 8

Anion concentration profile for a hydrogel scaffold immersed in solution.

Figure 9

Electric potential distribution for a hydrogel scaffold immersed in solution.

Figure 10

Transient variation of quantities for a hydrogel scaffold immersed in solution: (a) cation concentration, (b) anion concentration, (c) electric potential.