Cao Yuan, Zhao Gang, Panhwar Fazil, Zhang Xiaozhang, Chen Zhongrong, Cheng Lin, Zang Chuanbao, Liu Feng, Zhao Yuanjin, He Xiaoming
Department of Electronic Science and Technology, University of Science and Technology of China, Hefei 230027, Anhui, China.
Department of Emergency Surgery, Qilu Hospital, Shandong University, Jinan, Shandong, China.
Adv Mater Technol. 2019 Jan;4(1). doi: 10.1002/admt.201800289. Epub 2018 Oct 17.
Injectable stem cell-hydrogel constructs hold great potential for regenerative medicine and cell-based therapies. However, their clinical application is still challenging due to their short shelf-life at ambient temperature and the time-consuming fabrication procedure. Banking the constructs at cryogenic temperature may offer the possibility of "off-the-shelf" availability to end-users. However, ice formation during the cryopreservation process may compromise the construct quality and cell viability. Vitrification, cooling biological samples without apparent ice formation, has been explored to resolve the challenge. However, contemporary vitrification methods are limited to very small volume (up to 0.25 ml) and/or need highly toxic and high concentration (up to ~8 M) of permeable cryoprotectants (pCPAs). Here, we show that polytetrafluoroethylene (PTFE, best known as Teflon for making non-stick cookware) capillary is flexible and unusually stable at a cryogenic temperature. By using the PTFE capillary as a flexible cryopreservation vessel together with alginate hydrogel microencapsulation and FeO nanoparticle-mediated nanowarming to suppress ice formation, massive-volume (10 ml) vitrification of cell-alginate hydrogel constructs with a low concentration (2.5 M) of pCPA can be achieved. This may greatly facilitate the use of stem cell-based constructs for tissue regeneration and cell based therapies in the clinic.
可注射的干细胞 - 水凝胶构建体在再生医学和基于细胞的治疗方面具有巨大潜力。然而,由于它们在室温下保质期短以及制造过程耗时,其临床应用仍然具有挑战性。在低温下储存构建体可能为终端用户提供“现货供应”的可能性。然而,冷冻保存过程中的冰形成可能会损害构建体质量和细胞活力。玻璃化,即冷却生物样品而不形成明显的冰,已被探索用于解决这一挑战。然而,当代的玻璃化方法仅限于非常小的体积(高达约0.25毫升)和/或需要高毒性和高浓度(高达约8 M)的渗透性冷冻保护剂(pCPA)。在这里,我们表明聚四氟乙烯(PTFE,最出名的是用于制造不粘锅的特氟龙)毛细管在低温下具有柔韧性且异常稳定。通过将PTFE毛细管用作柔性冷冻保存容器,结合藻酸盐水凝胶微囊化和FeO纳米颗粒介导纳米加热以抑制冰形成,可以实现使用低浓度(约2.5 M)pCPA对大量体积(10毫升)的细胞 - 藻酸盐水凝胶构建体进行玻璃化。这可能极大地促进基于干细胞的构建体在临床组织再生和基于细胞的治疗中的应用。