title: Alginate Hydrogel Microencapsulation Inhibits Devitrification and Enables Large-Volume Low-CPA Cell Vitrification.
abstract: Cryopreservation of stem cells is important to meet their ever-increasing demand by the burgeoning cell-based medicine. The conventional slow freezing for stem cell cryopreservation suffers from inevitable cell injury associated with ice formation and the vitrification (i.e., no visible ice formation) approach is emerging as a new strategy for cell cryopreservation. A major challenge to cell vitrification is intracellular ice formation (IIF, a lethal event to cells) induced by devitrification (i.e., formation of visible ice in previously vitrified solution) during warming the vitrified cells at cryogenic temperature back to super-zero temperatures. Consequently, high and toxic concentrations of penetrating cryoprotectants (i.e., high CPAs, up to ~8 M) and/or limited sample volumes (up to ~2.5 μl) have been used to minimize IIF during vitrification. We reveal that alginate hydrogel microencapsulation can effectively inhibit devitrification during warming. Our data show that if ice formation were minimized during cooling, IIF is negligible in alginate hydrogel-microencapsulated cells during the entire cooling and warming procedure of vitrification. This enables vitrification of pluripotent and multipotent stem cells with up to ~4 times lower concentration of penetrating CPAs (up to 2 M, low CPA) in up to ~100 times larger sample volume (up to ~250 μl, large volume).
authors.affiliation: Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, USA. Department of Mechanical Engineering, The Ohio State University, Columbus, OH 43210, USA. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA.
authors.forename: Haishui
authors.initials: H
authors.lastname: Huang
authors.affiliation: Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, USA. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA.
authors.forename: Jung Kyu
authors.initials: JK
authors.lastname: Choi
authors.affiliation: Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, USA. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Rao
authors.affiliation: Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, USA. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA.
authors.forename: Shuting
authors.initials: S
authors.lastname: Zhao
authors.affiliation: Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, USA. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA.
authors.forename: Pranay
authors.initials: P
authors.lastname: Agarwal
authors.affiliation: Center for Biomedical Engineering, Department of Electronic Science and Technology, University of Science and Technology of China, Hefei, Anhui 230027, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Zhao
authors.affiliation: Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, USA. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA. Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: He
keywords: Microcapsule; cryomicroscopy; cryopreservation; inhibition; stem cells