Supplementary material from "Cryopreservation of hematopoietic stem cells using a zwitterion"

Zwitterions, which have low cytotoxicity among ionic liquids, are expected to be adopted in various applications across life sciences. We previously reported that zwitterions can be used as cryoprotectants, and that zwitterion/dimethyl sulfoxide (DMSO) aqueous solutions have high cryoprotective effects. Although cryopreservation of established cell lines has been performed using zwitterions, this method has not yet been applied to primary or stem cells. In this study, we verified whether primary hematopoietic stem cells could be efficiently cryopreserved using the zwitterion/DMSO aqueous solutions. The viable number of hematopoietic stem cells cryopreserved using zwitterion/DMSO/water (5/5/90, w/w/w) was comparable to that using LaboBankerTM, a commercial freezing medium. The number was also higher than those after cryopreservation with DMSO/Albumin solution/water (10/20/70, v/v/v), which is commonly used in cryopreservation of hematopoietic stem cells. This suggests that the zwitterion/DMSO aqueous solution can be used for cryopreservation of hematopoietic stem cells.