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

项目摘要/摘要 在这项提案中，我们的目标是开发两种不同的生物材料系统来改善营养和氧气。 以细胞为基础的临床胰岛移植(CIT)平台治疗1型糖尿病的有效性 糖尿病(T1 DM)。这项工作的动机是缺乏持久的氧气系统 补充移植的产生胰岛素的细胞，以及有限的优化支架 促进称职和完整的种植体血管形成。 T1 DM影响着超过125万美国人，预计到2050年将翻两番。之前的治疗尝试 由于低氧条件和移植物血管形成延迟，通过胰岛移植的T1 DM是有限的。 我们实验室公布的初步数据表明，包括一种生物相容性的， 名为OxySite的产氧复合材料与移植的胰岛素产生细胞一起可以导致 以延长细胞存活和移植后胰岛素的产生。通过立即输送局部氧气 移植后，这种方法应该弥合初始移植和建立 有效的血管形成。在这里，我们试图操纵原始的几何和材料属性 OxySite原型，以增强几何灵活性和氧气运动控制。此外，人们认识到， 传统的血管化技术不能为移植部位的细胞提供及时的支持，因为 内源性细胞渗入和组织成细胞基移植物的过程延长。在此，我们寻求 确定引导血管形成的最佳几何形状。总体而言，我们假设通过设计一个 模块化产氧微珠平台，以适应多个移植部位和释放要求， 与灵活的脚手架相结合，利用几何形状和孔径来加速 血管化，移植的细胞在移植后的所有时间段都可以得到支持。 这两个平台的构建和实施将对CIT产生重大影响 应用，以及其他基于细胞的疗法。此外，我们预计它们还将提供有价值的见解 用于控制治疗释放的材料的设计和血管形成的机制。我们的 实验室此前使用生物材料不仅改善了CIT平台，还揭示了关键的关系 参与细胞植入和长期功能。这些先前研究中概述的技术将适用于 作为拟议工作的起点。在目标1中，我们将探索是否产生孔隙度、调制 OxySite材料配方，并应用限速聚合物可以制造模块化的氧气- 世代平台。我们将利用一个模型胰岛移植平台来进一步表征这一新平台。 对于目标2，我们将使用3D打印设计和制造灵活的脚手架，以允许可配置的孔径大小 和几何学。我们将使用体外预血管形成的方法快速测试不同的孔大小，以获得最佳的 在进行皮下生物相容性模型之前的血管形成。

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.