Inhibition Effect of Ti3C2Tx MXene on Ice Crystals Combined with Laser-Mediated Heating Facilitates High-Performance Cryopreservation

The phenomena of ice formation and growth are of great importance for climate science, regenerative medicine, cryobiology, and food science. Hence, how to control ice formation and growth remains a challenge in these fields and attracts great interest from widespread researchers. Herein, the ice regulation ability of the two-dimensional MXene Ti3C2Tx in both the cooling and thawing processes is explored. Molecularly speaking, the ice growth inhibition mechanism of Ti3C2Tx MXene is ascribed to the formation of hydrogen bonds between functional groups of −O–, −OH, and −F distributed on the surface of Ti3C2Tx and ice/water molecules, which was elucidated by the molecular dynamics simulation method. In the cooling process, Ti3C2Tx can decrease the supercooling degree and inhibit the sharp edge morphology of ice crystals. Moreover, taking advantage of the outstanding photothermal conversion property of Ti3C2Tx, rapid ice melting can be achieved, thus reducing the phenomena of devitrification and ice recrystallization. Based on the ice restriction performance of Ti3C2Tx mentioned above, Ti3C2Tx is applied for cryopreservation of stem-cell-laden hydrogel constructs. The results show that Ti3C2Tx can reduce cryodamage to stem cells induced by ice injury in both the cooling and thawing processes and finally increase the cell viability from 38.4% to 80.9%. In addition, Ti3C2Tx also shows synergetic antibacterial activity under laser irradiation, thus realizing sterile cryopreservation of stem cells. Overall, this work explores the ice inhibition performance of Ti3C2Tx, elucidates the physical mechanism, and further achieves application of Ti3C2Tx in the field of cell cryopreservation.