Engineering Modular Oxygen-generating, Pro-vasculogenic Biomaterial Platforms for Cell-Based Therapies

项目总结/摘要 在这个建议中，我们的目标是开发两种不同的生物材料系统，以改善营养和氧气 基于细胞的临床胰岛移植（CIT）平台治疗1型糖尿病的可用性 糖尿病（T1 DM）。这项工作的动机是缺乏持久的氧气系统 补充移植的胰岛素产生细胞，以及支架的有限优化 促进有效和完全的植入物血管化。 T1 DM影响超过125万美国人，预计到2050年将翻两番。以前的治疗尝试 由于缺氧条件和移植物血管化延迟，通过胰岛移植治疗T1 DM是有限的。 来自我们实验室的已发表和初步数据表明， 产氧复合材料（称为OxySite）与移植的产胰岛素细胞一起可以导致 延长移植后细胞存活和胰岛素产生。通过立即输送局部氧气 移植后，这种方法应该弥合最初移植和建立之间的差距， 有能力的血管化。在这里，我们试图操纵原始的几何形状和材料属性， OxySite原型可增强几何灵活性和氧动力学控制。此外，人们认识到， 传统的血管化技术不能在移植部位为细胞提供及时的支持 内源性细胞浸润和组织化成细胞基移植物的延长过程。在此，我们寻求 确定用于引导血管形成的最佳几何形状。总的来说，我们假设通过工程设计， 模块化产氧微珠平台，以适应多个移植部位和释放要求， 结合柔性支架，其利用几何形状和孔径来加速 通过血管化，可以在移植后的所有时间段支持移植的细胞。 这两个平台的构建和实施将为CIT提供重大改进 应用以及其他基于细胞的疗法。此外，我们预计它们也将提供宝贵的见解， 用于控制治疗释放的材料的设计和血管形成的机制。我们 一个实验室以前使用生物材料，不仅改善了CIT平台，还揭示了关键的关系 参与细胞移植和长期功能。这些先前研究中概述的技术将有助于 作为拟议工作的起点。在目标1中，我们将探讨是否产生孔隙度，调制 OxySite材料配方和施加限速聚合物可以允许制造模块化的氧- 生成平台。我们将利用模型胰岛移植平台进一步表征这种新平台。 对于目标2，我们将使用3D打印设计和制造灵活的支架，以允许可配置的孔径 和几何学我们将使用体外预血管化方法快速测试不同孔径的最佳 血管形成，然后进行皮下生物相容性模型。

PROJECT SUMMARY/ABSTRACT In this proposal, we aim to develop two distinct biomaterial systems for improving nutrient and oxygen availability within cell-based clinical islet transplantation (CIT) platforms for the treatment of type 1 diabetes mellitus (T1DM). The motivation for this work is the lack of durable systems for oxygen supplementation of transplanted, insulin-producing cells, as well as the limited optimization of scaffolds for facilitating competent and complete implant vascularization. T1DM affects over 1.25 million Americans and is expected to quadruple by 2050. Previous attempts to treat T1DM through the transplantation of islets is limited due to hypoxic conditions and delayed graft vascularization. Published and preliminary data from our laboratory has demonstrated that the inclusion of a biocompatible, oxygen-generating composite material, termed OxySite, alongside transplanted insulin-producing cells can lead to prolonged cell survival and insulin production post-transplantation. By delivering local oxygen immediately post-transplantation, this approach should bridge the gap between initial transplant and the establishment of competent vascularization. Herein, we seek to manipulate the geometry and material properties of the original OxySite prototypes to enhance geometric flexibility and oxygen kinetic control. In addition, it is recognized that traditional vascularization techniques fail to provide timely support for cells at the site of transplant due to the prolonged process for endogenous cell infiltration and organization into cell-based grafts. Herein, we seek to identify an optimal geometry for guiding vascularization. Overall, we hypothesize that through engineering a modular oxygen-generating microbead platform to fit multiple transplant sites and release requirements, in conjunction with a flexible scaffolding that utilizes geometry and pore size to accelerate the process of vascularization, transplanted cells can be supported at all time periods post transplantation. Fabrication and implementation of these two platforms would provide a significant improvement to CIT applications, as well as other cell-based therapies. Furthermore, we anticipate they will also give valuable insight into the design of materials for controlled therapeutic release and into the mechanisms of vascularization. Our laboratory has previously used biomaterials to not only improve CIT platforms but also reveal crucial relationships involved in cell engraftment and long-term function. The techniques outlined in these previous studies will serve as a starting point for the proposed work. In Aim 1, we will explore whether generating porosity, modulating OxySite material formulation, and applying a rate limiting polymer can permit fabrication of a modular, oxygen- generation platform. We will further characterize this new platform utilizing a model islet transplantation platform. For Aim 2, we will design and fabricate a flexible, scaffolding using 3D printing to allow for configurable pore size and geometry. We will use an in vitro pre-vascularization method for rapid testing of varying pore sizes for optimal vasculature formation before proceeding to a subcutaneous biocompatibility model.