Minimizing the role of cryoprotectant toxicity for cryopreservation

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DESCRIPTION (provided by applicant): Long-term biopreservation of cells and tissues has a broad impact in multiple fields including tissue engineering, regenerative medicine, stem cells, blood banking, animal strain preservation (biodiversity protection), clinical sample storage, transplantation medicine and in vitro drug testing. Vitrification (ice/crystal-free cryopreservatio) has emerged as a novel approach over traditional slow freezing methods. Although vitrification minimizes mechanical damage due to ice crystal nucleation, it suffers from toxicity due to high concentrations of cryoprotectant agents (CPAs). The current vitrification methods require extremely high levels of CPAs of up to 8.2 M that are cytotoxic and cause osmotic shock. Also, the lengthy manual processing steps of current vitrification methods add to the technical complexity, require highly trained technicians, and result in variations between users. For instance, low CPA-level vitrification has immense potential for the stem cells compared to other methods in preserving their functionality. Recently, we demonstrated that we can achieve vitrification at ultra-rapid freezing and thawing rates with as low as 1.5M CPA concentration. We are adapting this new knowledge to the vital needs of cell cryopreservation at the clinic including discarded anonymous human oocytes. This proposal investigates a new experimental strategy to minimize the CPA concentrations and improve clinical outcomes using novel technologies (i.e., nanoliter droplet vitrification). These steps are facilitated by theoretical understanding o the underlying mechanisms governing vitrification. The expected outcome of this study is a closed-system platform technology with broad applications to human cell (e.g., hepatocytes, oocytes, sperm, stem cells), tissues (e.g., blood), micro-tissues (e.g., embryoid bodies, islets) covering areas of reproductive medicine, tissue engineering and regenerative medicine as well as to wild life preservation. These studies can also significantly impact the care of infertile couples and facilitate fertility preservation.