Ice Free Vitrification and nanowarming of large cartilage samples for transplantation

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Resurfacing of articular cartilage with cold stored osteochondral allografts is employed clinically for repair of trauma and osteoarthritis-induced articular cartilage surface damage. Chondrocyte viability of transplanted articular cartilage is accepted as one of the determinants of outcome following osteochondral allograft transplantation. We have previously developed an ice-free vitrification method of cryopreservation that maintains excellent chondrocyte viability in animal model and human articular cartilage. The chondrocytes survive vitrification due to the absence of ice formation during cooling and warming of 1-3mL samples. However, it has not been possible to rewarm larger samples due to ice nucleation during rewarming that results in loss of chondrocyte viability. The innovation in this proposal relates to a new rewarming method that does not have the limitations of boundary convection warming that should be effective for samples up to 50mL in volume. This rewarming method utilizes radio frequency induced heating of magnetic iron nanoparticles. We will optimize nanowarming of full thickness osteocartilage storage for maintenance of both chondrocyte viability and extracellular matrix integrity. This objective will be developed in two specific aims to optimize nanowarming variables and scaleup from 5mL to 30-50mL volumes. Nanowarmed chondrocyte viability, chemistry, and biomaterial properties will be compared with untreated fresh control tissue. The nanowarming conditions that provides the best preservation of chondrocytes with minimal if any cartilage biomaterial changes will be selected for further investigation in vivo and translation to human cartilage in a subsequent Phase II SBIR application.