Department of Physics, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
University of Ottawa Heart Institute, Division of Cardiology, Department of Medicine, University of Ottawa, Ottawa K1Y 4W7, Canada.
Biomed Mater. 2023 Jul 26;18(5). doi: 10.1088/1748-605X/ace6e8.
Current cell-based strategies for repairing damaged tissue often show limited efficacy due to low cell retention at the site of injury. Encapsulation of cells within hydrogel microcapsules demonstrably increases cell retention but benefits can be limited due to premature cell escape from the hydrogel microcapsules and subsequent clearance from the targeted tissue. We propose a method of encapsulating cells in agarose microcapsules that have been modified to increase cell retention by providing cell attachment domains within the agarose hydrogel allowing cells to adhere to the microcapsules. We covalently modified agarose with the addition of the cell adhesion peptide, RGD (arginine, glycine, aspartic acid). We then used a microfluidic platform to encapsulate single cells within 50 μm agarose microcapsules. We tracked encapsulated cells for cell viability, egress from microcapsules and attachment to microcapsules at 2 h, 24 h, and 48 h after encapsulation. Many encapsulated cells eventually egress their microcapsule. Those that were encapsulated using RGD-modified agarose adhered to the outer surface of the microcapsule following egress. NIH 3T3 cells showed nearly 45% of egressed cells attached to the outside of RGD modified agarose microcapsules, while minimal cellular adhesion was observed when using unmodified agarose. Similarly, human umbilical vein endothelial cells had up to 33% of egressed cells attached and explant-derived cardiac cells showed up to 20% attachment with the presence of RGD binding domains within the agarose microcapsules.
目前，基于细胞的策略修复受损组织的效果通常有限，因为在损伤部位的细胞保留率低。将细胞包封在水凝胶微胶囊中可以明显增加细胞保留率，但由于细胞过早从水凝胶微胶囊中逸出并随后从靶向组织中清除，其益处可能受到限制。我们提出了一种在琼脂糖微胶囊中包封细胞的方法，该方法通过在琼脂糖水凝胶中提供细胞附着结构域来增加细胞保留率，从而允许细胞附着在微胶囊上。我们通过添加细胞粘附肽 RGD（精氨酸、甘氨酸、天冬氨酸）对琼脂糖进行了共价修饰。然后，我们使用微流控平台将单个细胞封装在 50μm 的琼脂糖微胶囊中。我们在封装后 2 h、24 h 和 48 h 时跟踪封装细胞的细胞活力、从微胶囊中逸出以及与微胶囊的附着。许多封装的细胞最终会逸出微胶囊。使用 RGD 修饰的琼脂糖封装的细胞在逸出后会附着在微胶囊的外表面上。NIH 3T3 细胞显示出近 45%的逸出细胞附着在 RGD 修饰的琼脂糖微胶囊的外表面上，而使用未修饰的琼脂糖时观察到很少的细胞粘附。同样，人脐静脉内皮细胞中多达 33%的逸出细胞附着，而在琼脂糖微胶囊中存在 RGD 结合结构域时，衍生的心肌细胞附着率高达 20%。
