Department of Electronic Science and Technology, University of Science and Technology of China, Hefei, Anhui 230027, China.
Biomater Sci. 2018 Nov 20;6(12):3139-3151. doi: 10.1039/c8bm01004h.
Constructs of magnetic nanocomposite hydrogels microencapsulated with stem cells are of great interest as smart materials for tissue engineering and regenerative medicine. Due to the short shelf life of such biocomposites at an ambient temperature, their long-term storage and banking at cryogenic temperatures are essential for the "off-the-shelf" availability of such biocomposites for widespread clinical applications. However, high-quality cryogenic recovery of stem cell-nanocomposite hydrogel constructs has not yet been achieved due to the damage to cells and/or microstructures of hydrogel constructs caused by ice formation, particularly during warming from cryogenic temperatures. Herein, stem cell-magnetic nanocomposite hydrogel constructs, which have an inherent magnetothermal property provided by embedded magnetic nanoparticles, are explored to achieve ultra-rapid cryogenic warming. The binding of water molecules by the hydrogel combined with the magnetothermal heating greatly suppressed ice formation during both cryogenic cooling and warming. Thus, the cryogenic recovery of nanocomposite hydrogel constructs with intact microstructures and fully functional stem cells from ultra-low temperatures was successfully achieved. We further demonstrated that magnetic nanocomposite hydrogels microencapsulated with stem cells could be conveniently manipulated for a self-assembled 3D culture. Together, we have developed a highly efficient and easy-to-perform approach for the cryogenic recovery of stem cell-encapsulated magnetic nanocomposite hydrogel constructs. Our results will facilitate the applications of such stem cell-magnetic nanocomposite hydrogels in regenerative medicine and tissue engineering.
磁性纳米复合水凝胶微囊化干细胞构建体作为组织工程和再生医学的智能材料具有很大的研究兴趣。由于这些生物复合材料在环境温度下的保质期很短，因此需要在低温下长期储存和保存，以便在广泛的临床应用中“随时可用”这些生物复合材料。然而，由于冰晶形成对细胞和/或水凝胶构建体微结构的破坏，特别是在从低温升温时，尚未实现高质量的干细胞-纳米复合水凝胶构建体的低温恢复。在此，探索了具有内置磁热特性的磁性纳米复合水凝胶构建体，以实现超快速低温加热。水凝胶与磁热加热结合，使水分子结合，在低温冷却和升温过程中大大抑制了冰晶的形成。因此，成功地从超低温度实现了具有完整微结构和功能完整的干细胞的纳米复合水凝胶构建体的低温恢复。我们进一步证明了可以方便地操纵包埋有干细胞的磁性纳米复合水凝胶，以进行自组装的 3D 培养。总之，我们开发了一种高效且易于执行的方法，用于低温恢复包埋有干细胞的磁性纳米复合水凝胶构建体。我们的研究结果将促进此类干细胞-磁性纳米复合水凝胶在再生医学和组织工程中的应用。
