Sulfoxide-functional trehalose enhances DMSO-free cryopreservation of mammalian cells

Cell cryopreservation is crucial for biomedicine, and the addition of cryoprotectants (CPAs) to protect cells from cryoinjuries is essential at low temperatures. Trehalose (Tre) has been considered a biocompatible CPA because of its unique physicochemical properties, which could provide cryoprotection to cells during cryopreservation by its interaction with cell membrane phospholipids. Nonetheless, there were few studies on the synthesis of Tre-based CPAs. Here, we reported a feasible solution to further improve the cell cryopreservation efficiency by modifying Tre with sulfoxide functional groups, which enabled dimethyl sulfoxide (DMSO)-free cryopreservation of cells. Compared with unmodified Tre, the sulfoxide-modified Tre (Tre-S) could further protect cells from cryoinjuries. At the optimal CPA concentration (8% Tre-S), the survival rate of L929 cells was up to 88.5% after cryopreservation, and the recovered cells could maintain their normal cell biological behaviors. The differential scanning calorimetry (DSC) and ice recrystallization inhibiting (IRI) tests show that Tre-S has good melting point reduction and IRI activities. Compared with DMSO, the Tre-S had good biocompatibility. This study may provide an alternative method for DMSO-free cell cryopreservation.