140 The importance of hydrophobic moieties in ice recrystallization inhibitors

Abstract

Ice recrystallization during thawing after cryopreservation results in extensive cellular damage that ultimately leads to cell death and decreased cell viabilities. This is a significant problem particularly with cryopreserved cells utilized in various regenerative medicine therapies. Given the success of these therapies to treat spinal cord injury, cartilage lesions, and cardiac disease, the development of new and improved cryprotectants that minimize cell damage during freeze-thawing and improve cell viability post-cryopreservation are urgently required. Our laboratory has demonstrated that carbohydrate-based hydrogelators can be potent inhibitors of ice recrystallization. While our studies have indicated that a delicate balance between hydrophobic and hydrophilic interactions is crucial for ice recrystallization inhibition (IRI) activity, the essential structural features necessary for potent IRI activity remain unknown. To address this issue, we synthesized and assessed the IRI activity of structurally diverse amino acid-based surfactants/gelators and anti-ice nucleating using a splat-cooling assay. The results indicate that long alkyl chains and increased hydrophobicity are important for potent IRI activity and that the position of these alkyl chains is essential. Additionally, no correlation was found between IRI activity and critical micelle concentrations, gelation or anti-ice nucleation activity although the counterion of some surfactants did affect IRI activity. The results of our study will facilitate the design of improved ice recrystallization inhibitors for medical, commercial and industrial applications. Source of funding: None declared. Conflict of interest: None declared. abalcerzak@uottawa.ca