Cryopreservation of articular cartilage. Part 3: The liquidus-tracking method

Area of Science:

• Biomedical Engineering
• Tissue Engineering
• Cryobiology

Background:

• Current cryopreservation methods for cartilage grafts are unsatisfactory.
• Isolated chondrocytes can be cryopreserved, but whole grafts cannot be preserved effectively.
• Ice crystal formation during cryopreservation damages cartilage tissue.

Purpose of the Study:

• To develop a novel cryopreservation method for cartilage surgical grafts.
• To avoid ice crystal formation and the need for rapid warming during cartilage cryopreservation.
• To assess the viability and functionality of cryopreserved cartilage grafts.

Main Methods:

• Investigated cryoprotectant penetration and chondrocyte osmotic stress resistance.
• Evaluated existing vitrification methods for cartilage, noting their dependence on rapid warming.
• Developed and tested a 'liquidus-tracking' method to prevent ice crystallization during cooling and warming.

Main Results:

• The liquidus-tracking method completely avoids ice crystallization in cartilage grafts.
• Cryopreserved cartilage using this method demonstrated 70% of fresh control GAG synthesis.
• Low cooling and warming rates are feasible, suitable for bulky grafts in Tissue Banks.

Conclusions:

• The liquidus-tracking method offers a promising solution for cartilage graft cryopreservation.
• This technique preserves chondrocyte viability and extracellular matrix synthesis.
• The method's suitability for Tissue Bank processing of surgical grafts is highlighted.