Institute of Polymer Science and Technology (ICTP-CSIC), Madrid, Spain; CIBER-BBN, Health Institute Carlos III, Madrid, Spain.
Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA; Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA.
Mater Sci Eng C Mater Biol Appl. 2021 Jan;120:111716. doi: 10.1016/j.msec.2020.111716. Epub 2020 Nov 10.
Human mesenchymal stem cells (hMSCs) are an attractive source for cell therapies because of their multiple beneficial properties, i.e. via immunomodulation and secretory factors. Microfluidics is particularly attractive for cell encapsulation since it provides a rapid and reproducible methodology for microgel generation of controlled size and simultaneous cell encapsulation. Here, we report the fabrication of hMSC-laden microcarriers based on in situ ionotropic gelation of water-soluble chitosan in a microfluidic device using a combination of an antioxidant glycerylphytate (GPhy) compound and tripolyphosphate (TPP) as ionic crosslinkers (GPhy:TPP-microgels). These microgels showed homogeneous size distributions providing an average diameter of 104 ± 12 μm, somewhat lower than that of control (127 ± 16 μm, TPP-microgels). The presence of GPhy in microgels maintained cell viability over time and upregulated paracrine factor secretion under adverse conditions compared to control TPP-microgels. Encapsulated hMSCs in GPhy:TPP-microgels were delivered to the subcutaneous space of immunocompromised mice via injection, and the delivery process was as simple as the injection of unencapsulated cells. Immediately post-injection, equivalent signal intensities were observed between luciferase-expressing microgel-encapsulated and unencapsulated hMSCs, demonstrating no adverse effects of the microcarrier on initial cell survival. Cell persistence, inferred by bioluminescence signal, decreased exponentially over time showing relatively higher half-life values for GPhy:TPP-microgels compared to TPP-microgels and unencapsulated cells. In overall, results position the microfluidics generated GPhy:TPP-microgels as a promising microcarrier for supporting hMSC survival and reparative activities.
人骨髓间充质干细胞（hMSCs）因其多种有益特性，如免疫调节和分泌因子，是细胞治疗的有吸引力的来源。微流控技术特别适合用于细胞包封，因为它提供了一种快速且可重复的方法来生成具有受控尺寸的微凝胶并同时进行细胞包封。在这里，我们报告了在微流控装置中使用抗氧化剂甘油酸酯（GPhy）化合物和三聚磷酸酯（TPP）作为离子交联剂原位离子凝胶化水溶性壳聚糖来制备负载 hMSC 的微载体（GPhy：TPP-微凝胶）。这些微凝胶显示出均匀的尺寸分布，提供了平均直径为 104±12μm 的微凝胶，略低于对照（127±16μm，TPP-微凝胶）。与对照 TPP-微凝胶相比，微凝胶中存在的 GPhy 保持了细胞活力随时间的延长，并在不利条件下上调旁分泌因子的分泌。通过注射将负载 hMSC 的 GPhy：TPP-微凝胶递送至免疫功能低下小鼠的皮下空间，并且递送过程与未封装细胞的注射一样简单。注射后立即，观察到表达荧光素酶的微凝胶封装和未封装 hMSC 之间的信号强度相等，表明微载体对初始细胞存活没有不利影响。细胞存活通过生物发光信号推断，随着时间的推移呈指数下降，表明 GPhy：TPP-微凝胶相对于 TPP-微凝胶和未封装细胞具有相对较高的半衰期值。总体而言，结果表明微流控技术生成的 GPhy：TPP-微凝胶是一种有前途的微载体，可支持 hMSC 的存活和修复活性。
