Analysis of Cryoprotectant Concentration During Cryopreservation in Articular Cartilage Sample Using Homogeneous and...

Area of Science:

• Biomedical Engineering
• Materials Science
• Biophysics

Background:

• Cryopreservation of articular cartilage is vital for tissue engineering and regenerative medicine.
• Understanding cryoprotectant agent (CPA) diffusion is critical for cell viability during cryopreservation.
• Accurate modeling of CPA diffusion requires considering the complex material properties of biological tissues.

Purpose of the Study:

• To compute the effective diffusion coefficient of CPA in articular cartilage during cryopreservation.
• To compare the predictive accuracy of homogeneous and porous material models for CPA diffusion.
• To investigate the influence of temperature and CPA concentration on the effective diffusion coefficient.

Main Methods:

• Coupling mass transfer with the effective diffusion coefficient using Einstein-Stokes and Arrhenius models for homogeneous materials.
• Employing a porous medium model for mass transfer, strongly coupled with CPA concentration and weakly coupled with heat transfer (Fourier equation).
• Validating model predictions against experimental results for a selected cryopreservation method.

Main Results:

• The porous model yielded the lowest effective diffusion coefficient values.
• Maximal relative errors compared to experimental data were 15.82% (homogeneous, Einstein-Stokes), 5.20% (homogeneous, Arrhenius), and 24.96% (porous).
• Decreasing temperature and increasing dimethyl sulfoxide (DMSO) concentration reduced the effective diffusion coefficient.

Conclusions:

• The porosity of articular cartilage significantly impacts CPA diffusion dynamics.
• The chosen material model critically influences the accuracy of effective diffusion coefficient calculations.
• This comparative analysis provides insights for optimizing CPA concentrations and cooling rates in cartilage cryopreservation.