Chitosan-based nanocoatings for hypothermic storage of living cells

The formation of ultrathin chitosan-based nanocoating on HL-60 model cells and their protective function in hypothermic storage are presented. HL-60 cells are encapsulated in ultrathin shells by adsorbing cationic and anionic chitosan derivatives in a stepwise, layer-by-layer, procedure carried out in an aqueous medium under mild conditions. The chitosan-based films are also deposited on model lipid bilayer and the interactions are studied using ellipsometry and atomic force microscopy. The cells covered with the chitosan-based films and stored at 4 °C for 24 h express viability comparable to that of the control sample incubated at 37 °C, while the unprotected cells stored under the same conditions do not show viability. It is shown that the chitosan-based shell protects HL-60 cells against damaging effect of hypothermic storage. Such nanocoatings provide protection, mechanical stability, and support the cell membrane, while ensuring penetration of small molecules such as nutrients/gases what is essential for cell viability.