Cell encapsulation strategies using hydrogel beads have been considered as an alternative to immunosuppression in cell-based therapies. They rely on layer-by-layer (LbL) deposition of polymers to tune beads’ permeability, creating a physical barrier to the host immune system. However, the LbL approach can also create diffusion barriers, hampering the flow of essential nutrients and therapeutic cell products. In this work, the polyelectrolyte complex (PEC) methodology was used to circumvent the drawbacks of the LbL strategy by inducing hydrogel bead formation through the interaction of anionic methacrylated gellan gum (GG-MA) with cationic poly-l-lysine (PLL). The interfacial complexation between both polymers resulted in beads with a cell-friendly GG-MA hydrogel core surrounded by a PEC semipermeable membrane. The beads showed great in vitro stability over time, a semi-permeable behavior, and supported human adipose-derived stem cell encapsulation. Additionally, and regarding immune recognition, the in vitro and in vivo studies pointed out that the hydrogel beads behave as an immunocompatible system. Overall, the engineered beads showed great potential for hydrogel-mediated cell therapies, when immunoprotection is required, as when treating different metabolic disorders.

中文翻译：

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用于细胞疗法的甲基丙烯酸化结冷胶/聚-l-赖氨酸聚电解质复合珠

使用水凝胶珠的细胞封装策略已被认为是基于细胞疗法中免疫抑制的替代方案。它们依靠聚合物的逐层 (LbL) 沉积来调整珠子的渗透性，从而为宿主免疫系统创建物理屏障。然而，LbL 方法也会产生扩散障碍，阻碍必需营养素和治疗细胞产品的流动。在这项工作中，聚电解质复合物（PEC）方法被用来通过阴离子甲基丙烯酸酯化的结冷胶（GG-MA）与阳离子聚的相互作用诱导的水凝胶珠形成规避策略的LbL的缺点升-赖氨酸 (PLL)。两种聚合物之间的界面复合导致珠子具有细胞友好的 GG-MA 水凝胶核心，并被 PEC 半透膜包围。随着时间的推移，这些珠子在体外表现出良好的稳定性、半渗透性，并支持人类脂肪来源的干细胞封装。此外，关于免疫识别，体外和体内研究指出，水凝胶珠表现为免疫相容系统。总的来说，当需要免疫保护时，如治疗不同的代谢紊乱时，工程珠子在水凝胶介导的细胞疗法中显示出巨大的潜力。