Determining the Diffusion Coefficient for Articular Cartilage Modelled As Homogeneous and Porous Material

Porous materials are defined as materials consisting of a ‘matrix’ in which the voids are filled with gas or liquid. Porous materials also include biological tissues, because they consist of dispersed cells isolated by voids (pores) through which nutrients flow to all cells in them. An example of such tissue is articular cartilage, in which the size of the pores is estimated to be between 2 nm and 6 nm. The study involved determining the diffusion coefficient value for a selected tissue (articular cartilage) during cooling, assuming a model for homogeneous and porous material. The results obtained confirm that the applied material model impacts on the values of the diffusion coefficient. Higher coefficient values were obtained for the model taking into account the porosity of the sample than for the homogeneous material model. In addition, a decrease in temperature causes a decrease in the diffusion coefficient value. The results obtained can be used in the future to analyse the behaviour of a biological sample during the cryopreservation process.