Nanoparticle-Mediated Intracellular Delivery Enables Cryopreservation of Human Adipose-Derived Stem Cells Using Trehalose as the Sole Cryoprotectant

摘要

In this study, pH responsive genipin-crosslinked Pluronic F127-chitosan nanoparticles (GNPs) was synthesized to encapsulate trehalose for intracellular delivery to cryopreserve primary human adipose-derived stem cells (hADSCs). Trehalose is a disaccharide of glucose used by lower-organisms to survive extreme cold in nature and has been used to cryopreserve various biomacromolecules. However, it does not enter mammalian cells due to its highly hydrophilic nature and has only been used in combination with other cell-penetrating cryoprotectants such as DMSO to cryopreserve mammalian cells. Our data show that trehalose can be efficiently encapsulated in our GNPs for intracellular delivery, which enables cryopreservation of primary hADSCs using the nontoxic sugar as the sole cryoprotectant. This capability is important because the conventional approach of cryopreserving mammalian cells using highly toxic (at body temperature) cell-penetrating cryoprotectants requires multi-step washing of the cryopreserved cells to remove the toxic cryoprotectant for further use, which is time-consuming and associated with significant cell loss (~10% during each washing step). By contrast, the trehalose-cryopreserved cells can be used without washing, which should significantly facilitate the wide application of the burgeoning cell-based medicine.