Mechanistic insights into how water-network disorder determines the vitrification concentration in cryopreservation...

Cryopreservation enables long-term storage of biological materials using cryoprotective agents (CPAs) to suppress ice crystal formation and prevent cell damage. However, despite considerable efforts, a molecular-level understanding of how CPAs prevent ice-crystal formation has not yet been established, particularly one that generalizes across different CPAs. In this study, we correlate molecular factors derived from low-temperature molecular dynamics simulations with measured C_v (minimum concentration required for vitrification) across several CPAs. Specifically, tetrahedral order parameter analyses show that CPAs disrupt the natural tetrahedral structure of water to different degrees, and this disruption correlates strongly with C_v. Additionally, we show that clustering predicts C_v, relating CPA-induced changes in the H-bond network to vitrification ability. We establish a molecular connection between CPA-driven disruption of the water H-bond network and vitrification capability. We use this to predict the CPA efficiency of new compounds. The approach provides a route toward the first-principles design of effective CPA compositions.