Bioelectronics-embedded injectable hydrogel for neural regeneration

由于再生能力有限，神经损伤(如脊髓损伤)是一个衰弱的健康问题。 神经系统的能力。一种潜在的再生受损神经组织的方法是将 干细胞可以分化为神经元，并与宿主整合。为了提高细胞的活力和 在本地化方面，可注射水凝胶已被探索作为NSC的递送载体。然而，大多数可注射的 水凝胶缺乏微孔结构，不能促进细胞与细胞之间的相互作用，而细胞之间的相互作用是神经必不可少的 分化和功能性神经组织的形成。 在这项研究中，我们将开发一种可注射的微孔水凝胶，用于NSC的输送，可以 再生神经组织。可注射微孔制剂由复合微凝胶制成， 由甲基丙烯酸明胶(GelMA)和甲基丙烯酸化透明质酸(MeHA)组成。这些微凝胶形成了块状 通过双重交联机制的微孔水凝胶：(I)甲基丙烯酸酯的快速紫外光聚合 以及(Ii)微生物谷氨酰胺转氨酶(MTG)的酶促交联剂，也可促进组织粘连。这个 注射微凝胶的神经干细胞被包裹在微凝胶之间的间质微孔中，并且 会迅速扩散，并通过适当的细胞-细胞相互作用分化为神经元，导致功能性 神经网络。这与传统的可注射水凝胶形成对比，在水凝胶中包裹的细胞 被聚合物链包裹，禁止形态变化和细胞-细胞相互作用。我们 假设增强的细胞-细胞相互作用将导致更多的电活动神经元和功能 神经网络。我们将采用创新的生物电子网格(BioEM)来实现实时读数 整个脚手架的神经活动。来自BioEM的数据将允许统计比较 不同的微凝胶配方，并通知新的设计迭代。 为了达到本研究的主要目的，我们将首先合成和优化注射剂 可在紫外线照射下快速固化的微凝胶，具有高细胞存活率、细胞铺展和神经元 微囊化神经干细胞的分化。同时，将制造BioEM，它将与 微凝胶为基础的水凝胶，具有高细胞活力的神经干细胞胶囊。最后，BioEM将被用于 从水凝胶中包裹的神经干细胞中监测功能神经网络的发育。 到本项目结束时，将开发一种新的微孔水凝胶配方，具有潜在的 为神经组织再生输送神经干细胞。通过BioEM的嵌入式生物电子学将允许 连续的电生理读数，将通知水凝胶微凝胶的未来迭代。系统 证明了体外功能神经网络将是临床翻译的有前途的候选者。

Neural injuries (e.g. spinal cord injury) are a debilitating health problem due to the limited regenerative capacity of the nervous system. One potential way of regenerating damaged neural tissues is the delivery of stem cells that can differentiate into neurons and integrate with the host. To increase the cell viability and localization, injectable hydrogels have been explored as NSC delivery vehicles. However, most injectable hydrogels lack microporous structures and fail to promote cell-cell interactions which are essential for neural differentiation and functional neural tissue formation. In this research we will develop an injectable microporous hydrogel for NSC delivery that can regenerate neural tissues. The injectable microporous formulation is made of composite microgels, composed of methacrylated gelatin (GelMA) and methacrylated hyaluronic acid (MeHA). These microgels form a bulk microporous hydrogel via a dual crosslinking mechanism: (i) rapid UV photopolymerization of methacrylates and (ii) enzymatic crosslinking by microbial transglutaminase (mTG) which also promotes tissue adhesion. The NSCs that are injected with microgels are encapsulated in the interstitial micropores between microgels, and will spread rapidly, and differentiate into neurons with proper cell-cell interactions, resulting in a functional neural network. This is contrasted with the traditional injectable hydrogels in which the encapsulated cells are entrapped by the polymer chains and prohibited for morphological changes and cell-cell interactions. We hypothesize that the enhanced cell-cell interactions will lead to more electrically-active neurons and functional neural networks. We will adopt an innovative Bioelectronic Mesh (BioEM) to achieve real-time readouts of neural activity throughout the scaffolds. Data from the BioEM will allow for statistical comparisons between different microgel formulations and inform new design iterations. To achieve the main objective of this research, we will first synthesize and optimize the injectable microgels which rapidly cure upon UV irradiation with high cell viability, cell spreading and neuronal differentiation of the encapsulated NSCs. In parallel, BioEM will be fabricated which will integrate with the microgel-based hydrogel with high cell viability of the encapsulated NSCs. Finally, BioEM will be used to monitor the development of functional neural network from the NSCs encapsulated in the hydrogel. By the end of this project, a novel microporous hydrogel formulation will be developed with the potential to deliver NSCs for neural tissue regeneration. Embedded bioelectronics via the BioEM will allow for continuous electrophysiological readouts that will inform future iterations of the hydrogel microgel. Systems that demonstrate functional neural networks in vitro will be promising candidates for clinical translation.