Hypothermic Stem Cell Storage Using a Polypeptide Thermogel

Abstract

We report a polypeptide-based thermogel as a new tool for hypothermic storage of stem cells at ambient temperature (25 °C). Stem cells were suspended in the sol state (10 °C) of an aqueous poly(ethylene glycol)−poly(L-alanine) (PEG−PA) solution (4.0 wt %) in phosphate-buffered saline (PBS), which turned into a stem cell-incorporated gel by a heat-induced sol-to-gel transition. The cell harvesting procedure from the thermogels was simply performed through a gel-to-sol transition by diluting and cooling the system. More than 99% of stem cells died in PBS and Pluronic F127 thermogel (control thermogel) when the cells were stored at 25 °C for 7 days. The cell recovery rate from the PEG−PA thermogel (64%) was significantly greater than that from the commercially available HypoThermosol FRS preservation solution (HTS) (26%). Additionally, the surviving stem cells from the PEG− PA thermogel were healthier than those from HTS in terms of (1) expression of stemness biomarkers (NANOG, OCT4, and SOX2), (2) proliferation rate, and (3) differentiation potentials into osteogenic, chondrogenic, and adipogenic lineages. Membrane stabilization was suggested as a cell protection mechanism in the cytocompatible PEG−PA thermogel. The PEG−PA thermogel provides a convenient cytocompatible way for the storage and recovery of cells and thus is a promising tool for the transportation and short-term banking of cells.

Polysaccharide-Derived Ice Recrystallization Inhibitors with a Modular Design: The Case of Dextran-Based Graft Polymers

“…Larger ice crystals are fatal to cells because they induce terrible mechanical damage and osmotic shock . This phenomenon during thawing has negative impacts on the melting point ( T m ) and enthalpy ( H m ) that can be detected by DSC. , As shown in Figure S9a, SH-PVA 30 , which has been thought to be a potent ice recrystallization inhibitor, can depress the T m from −0.83 °C of DI water to −2.9 °C, and it can be further depressed to −3.14 °C with 10 wt % SH-PVA 80 . H m presents a similar tendency in which SH-PVA with higher DP demonstrates higher IRI activity, which is consistent with previous work (Figure S9b).…”

Extracellular Matrix-Mimetic Peptide Scaffolds Prolonged the Hypothermic Preservation of Stem Cells for Storage and Transportation

“…Little attention has been given to the methods of stem cell-based medicinal product preservation before their clinical application, and clinically acceptable methods of cell preservation are poorly developed. To allow enough time for recipient conditioning, cell product quality, and cell transportation between manufacturing facilities and clinical destinations, stem cell products require an effective short-term preservation method. − Cryopreservation is commonly used in stem cell storage and transportation by preserving the structural and functional integrity of cells under low temperatures. , Nevertheless, the inconvenience of the cooling procedures and the high cost of the preservation facilities are substantial limitations for long-distance transportation, especially in remote rural areas. − Thus, a simpler and better method is highly desired to replace cryopreservation for the short-term preservation of stem cells. In contrast to cryopreservation, hypothermic preservation at 2–8 °C offers a logistically easy and cost-effective option, which is a simplified, reproducible, and convenient storage system.…”