CAS Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China; Beijing Key Laboratory of Cryo-Biomedical Engineering, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China; School of Future Technology, University of Chinese Academy of Sciences, Beijing 100049, China.
CAS Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China; Beijing Key Laboratory of Cryo-Biomedical Engineering, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
Acta Biomater. 2020 Jan 15;102:403-415. doi: 10.1016/j.actbio.2019.11.023. Epub 2019 Nov 14.
High warming rates during cryopreservation are crucial and essential for successful vitrification. However, realizing a faster warming rate in low-concentration cryoprotective agents appears to be challenging for conventional warming process through convective heat transfer. Herein, we developed a liquid metal (LM) nanosystem that can act as a spatial source to significantly enhance the warming rates with near-infrared laser irradiation during the warming process. The synthetic Pluronic F127-liquid metal nanoparticles (PLM NPs) displayed multiple performances with uniform particle size, superior photothermal conversion efficiency (52%), repeatable photothermal stability, and low cytotoxicity. Particularly, it is more difficult for the liquid PLM NPs with less surface free energy to form crystal nucleation than other solid NPs such as gold and FeO, which is beneficial for the cooling process during cryopreservation. The viability of human bone marrow-derived mesenchymal stem cells postcryopreservation reached 78±3%, which is threefold higher than that obtained by the conventional warming method (25±6%). Additionally, the cells postcryopreservation maintained their normal attachment, proliferation, surface marker expression, and intact multilineage differentiation properties. Moreover, the results of mouse tails including blood vessel cryopreservation showed a relatively improved intact structure when using PLM NP rewarming compared with the results of conventional warming. The new LM nanosystem provides a universal platform for cryopreservation that is expected to have potential for widespread applications including bioengineering, cell-based medicine, and clinical translation. STATEMENT OF SIGNIFICANCE: In this study, we fabricated soft liquid metal nanoparticles with high photothermal conversion efficiency, repeatable photothermal stability, and low cytotoxicity. Particularly, soft liquid metal nanoparticles with less surface free energy and suppression effects of ice formation were first introduced to mediate cryopreservation. Superior ice-crystallization inhibition is achieved as a result of less crystal nucleation and ultrarapid rewarming during the freezing and warming processes of cryopreservation, respectively. Collectively, cryopreservation of human bone marrow stromal cells (HBMSCs) and mouse tails including blood vessels can be successfully performed using this new nanoplatform, showing great potential in the application of soft nanoparticles in cryopreservation.
高的升温速率在玻璃化冷冻过程中至关重要且必不可少。然而，在传统的通过对流热传递的升温过程中，在低浓度的细胞保护剂中实现更快的升温速率似乎具有挑战性。在此，我们开发了一种液态金属（LM）纳米系统，该系统可以作为空间源，在升温过程中通过近红外激光照射显著提高升温速率。合成的 Pluronic F127-液态金属纳米粒子（PLM NPs）表现出多种性能，具有均匀的粒径、优异的光热转换效率（52%）、可重复的光热稳定性和低细胞毒性。特别是，具有较少表面自由能的液态 PLM NPs 比其他固体 NPs（如金和 FeO）更难形成晶核，这有利于冷冻保存过程中的冷却。冷冻保存后人类骨髓间充质干细胞的存活率达到 78±3%，比传统升温方法（25±6%）高 3 倍。此外，冷冻保存后的细胞保持正常的附着、增殖、表面标志物表达和完整的多能分化特性。此外，使用 PLM NP 复温的小鼠尾巴包括血管的冷冻保存结果显示，与传统升温相比，相对提高了完整的结构。新的 LM 纳米系统为冷冻保存提供了一个通用平台，有望在生物工程、基于细胞的医学和临床转化等领域得到广泛应用。
在这项研究中，我们制备了具有高光热转换效率、可重复的光热稳定性和低细胞毒性的软液态金属纳米粒子。特别是，首次引入具有较少表面自由能和抑制冰形成作用的软液态金属纳米粒子来介导冷冻保存。在冷冻和复温过程中，分别通过较少的晶体成核和超快复温实现了卓越的冰结晶抑制。总的来说，使用这个新的纳米平台可以成功地进行人类骨髓基质细胞（HBMSCs）和包括血管的小鼠尾巴的冷冻保存，这表明软纳米粒子在冷冻保存中的应用具有很大的潜力。
