Cc René van Donkelaar

Mechanical stimulation to stimulate formation of a physiological collagen architecture in tissue-engineered cartilage; a numerical study

The load-bearing capacity of todays tissue-engineered (TE) cartilage is insufficient. The arcade-like collagen network in native cartilage plays an important role in its load-bearing properties. Inducing the formation of such collagen architecture in engineered cartilage can, therefore, enhance mechanical properties of TE cartilage. Considering the well-defined relationship between tensile strains and collagen alignment in the literature, we assume that cues for inducing this orientation should come from mechanical loading. In this study, strain fields prescribed by loading conditions of unconfined compression, sliding indentation and a novel loading regime of compression–sliding indentation are numerically evaluated to assess the probability that these would trigger a physiological collagen architecture. Results suggest that sliding indentation is likely to stimulate the formation of an appropriate superficial zone with parallel fibres. Adding lateral compression may stimulate the formation of a deep zone with perpendicularly aligned fibres. These insights may be used to improve loading conditions for cartilage tissue engineering.

EFFECTS OF ANOMALOUS DIFFUSION MECHANISMS IN DEVELOPING TISSUE ENGINEERED CONSTRUCTS

Many diffusive processes in biological systems refuse to obey the standard laws of diffusion. In normal diffusion, the diffusivity can be considered constant and the concentration of the diffusive particles follows Fick’s law. However, in highly heterogeneous materials such as tissues, the complex microgeometry of the medium imposes serious restrictions to the mobility of the particles. This scenario is known as anomalous diffusion. Experiments in diverse biological systems including diffusion in the extracellular space of the brain [1], morphogen movement in the extracellular environment [2], protein movement inside cells [3], identified anomalous, rather than Fickian, transport.Copyright