3D Microvascular Networks in Biomaterials Fabricated with Sacrificial Structures

描述（由申请人提供）：当前组织工程技术的主要限制之一是缺乏三维血管化的人工组织结构。当组织工程师试图形成更厚的细胞负载结构时，内部微血管网络（通过培养基或血液）为结构内部的细胞提供营养将变得必要。虽然来自半导体行业的技术已被用于在生物材料内部形成2D微流控结构，但目前制造3D微通道网络（多层堆叠和3D打印）的策略缓慢、困难且昂贵。我建议开发一种基于牺牲微纤维网络的技术，在生物材料内部形成复杂的三维流体微通道网络。使用标准棉花糖机和商店购买的砂糖形成超纤维网络。可以使用粘在微光纤网络上的更大的糖棒来形成宏通道接口。一旦完整的牺牲糖结构形成，将基质材料倒在糖上，然后交联。然后将整个结构浸入水中以溶解糖，在基质材料内部留下复杂的3D通道网络。我计划在研究开始时研究两种有前途的生物材料，聚乙二醇二丙烯酸酯（PEGDA），一种可光固化的水凝胶，聚癸二酸酯丙烯酸酯（PGSA），一种可光固化的可生物降解弹性体。这两种材料都被证明是细胞生长的优秀支架。一旦微通道网络在生物材料中形成，我将在通道壁上培养人脐静脉内皮细胞（HUVECs），形成一层内膜，允许非肝素化的血液流动而不会凝固。在这一步之后，我将在基质的大部分（可能需要制作多孔的）中播种细胞来形成结构。在所有细胞研究中，将使用标准荧光染料技术测量细胞活力。

DESCRIPTION (provided by applicant): One of the major limitations of current tissue engineering technology is the lack of 3D vascularlized artificial tissue constructs. As tissue engineers attempt to form thicker cell- laden constructs, an internal microvascular network to provide nutrients (via media or blood) to cells deep within the construct will become necessary. While techniques derived from the semiconductor industry have been used to form 2D microfluidic structures inside biomaterials, the current strategies for fabrication of 3D microchannel networks (multi-layer stacking and 3D printing) are slow, difficult, and expensive. I propose to develop a technique based on sacrificial microfiber networks to form complex 3D fluidic microchannel networks inside of biomaterials. The microfiber networks are formed using a standard cotton candy machine and store-bought granulated sugar. Macrochannel interfaces may be formed using larger sticks of sugar stuck to the microfiber network. Once the full sacrificial sugar structure is formed, a matrix material is poured over the sugar and then crosslinked. The entire construct is then immersed in water to dissolve the sugar, leaving a complex 3D network of channels inside the matrix material. I plan to investigate two promising biomaterials in the beginning of the study, polyethylene glycol diacrylate (PEGDA), a photocurable hydrogel, and polygylcerol sebacate acrylate (PGSA), a photocurable biodegradable elastomer. Both of these materials have been shown to act as excellent scaffolds for cell growth. Once the microchannel network is formed in the biomaterial, I will grow human umbilical vein endothelial cells (HUVECs) on the channel walls to form a lining that will allow non- heparinized blood flow without clotting. Following this step, I will form constructs with cells seeded in the bulk of the matrix (which may need to be made porous). During all cell studies, cell viability will be measured using standard fluorescent dye techniques. PUBLIC HEALTH RELEVANCE: The progress of modern tissue engineering depends on the ability to form 3D microvascular networks that are able to provide nutrients inside of artificial tissue constructs. Using a new technique based on sacrificial sugar structures, we will be able to produce these networks rapidly and inexpensively, thereby rendering the resulting vascularized artificial tissue constructs accessible to the patient.