  Freezing interface interacting with soft cells is a core issue in
cryopreservation. However, most of existing cryopreservation approaches face
challenges such as complex processing and poor controllability. Herein we
report a new, nanotechnology-based method to modulate interfacial interactions
between ice and cells via the premelting theory. Through the interfacial design
by controllably modifying biocompatible nanoshells on the surface of cells, the
effective Hamaker constant between cells and ice can be modified. The thickness
of premelted films between cells and ice is further regulated, and directional
migration of coated cells occurs in a thermal gradient to achieve directional
thawing of coated cells. The decreased mortality of freezing coated cells
suggests the premelting modulation in freezing and thawing can effectively
protect cells from mechanical damage of ice formation during freezing and ice
recrystallization during thawing.
