Layered Manufacture of Bioactive Porous TE Scaffolds

描述(由申请人提供)：据报道，美国普通人群中每年约有275,000例骨缺陷需要骨移植手术才能愈合。此外，有必要为越来越多的士兵和海军陆战队士兵提供护理，这些士兵和海军陆战队士兵因炸弹爆炸、弹药、严重坠落和参与伊拉克冲突的车辆事故而头部受重伤。这项建议中描述的研究针对的是修复临界大小的颅骨缺损这一临床问题。临界大小的颅骨缺损通常是由于原发瘤和转移性肿瘤切除导致的骨丢失，骨骼创伤后的骨丢失，或者是先天性畸形的结果。最终的手术目标是通过植入一种功能性的、可生物降解的、生物兼容的生物活性支架来修复缺损，这种支架将非法再生骨，并随着时间的推移与宿主骨完全结合。这项研究的总体目标是开发出准确制造适合骨再生的定制设计的富马酸聚丙烯(PPF)多孔支架的方法，并通过在大鼠骨髓基质细胞(MSCs)和成骨补充介质中的灌流生物反应器中培养使这些支架具有生物活性。为了实现这一目标，本项目将分为三个具体的目标：1)设计和制造一种灌流生物反应器，能够灌流定制的多孔支架；2)利用分层制造技术，在生物相容性聚合物PPF中设计和制造适合骨再生的多孔支架；3)使PPF多孔支架具有生物活性。本研究的第一部分将重点设计和制造一种灌流生物反应器，该反应器具有可互换的盒体，适合于定制支架的放置。PPF将按照先前公布的步骤合成，其相对分子质量分别为800-1000 Da和1,800-2000 Da。三维CAD将被用来设计定制的多孔脚手架，具有精确控制的外部和内部高度多孔、相互连接的建筑。支架将使用立体光刻技术制造，与大鼠骨髓间充质干细胞种植，并在灌流生物反应器中孵育4、8和12天。生物活性的程度将通过酶联免疫吸附试验和钙沉积程度来确定。这项研究将开发制造和生物学策略，以生产具有生物活性的患者专用支架，用于修复颌面部骨缺损。

DESCRIPTION (provided by applicant): There are approximately 275,000 skeletal defects a year reported in the U.S. general population that require bone graft procedures to achieve union. In addition, there is a need to provide care to the increasing number of soldiers and Marines suffering from critical head injuries caused by bomb blasts, munitions, serious falls and vehicle accidents to those engaged in the Iraq conflict. The research described in this proposal is directed towards this clinical problem of repairing critical-sized cranial defects. Critical sized cranial defects are often the result of bone loss due to the removal of primary and metastatic tumors, bone loss after skeletal trauma, or as a result of congenital deformity. The ultimate surgical goal is to repair the defect by implantation of a functional, biodegradable, biocompatible, bioactive scaffold that will illicit bone regeneration and over time fully integrate with the host bone. The overall goal of this research is to develop methods to accurately fabricate custom-designed polypropylene fumarate) (PPF) porous scaffolds suitable for bone regeneration and render those scaffolds bioactive by culturing in a perfusion bioreactor in the presence of rat marrow stromal cells (MSCs) and osteogenic supplemented media. To accomplish this goal, this project will be divided into three specific aims: 1) design and manufacture a perfusion bioreactor capable of perfusing custom porous scaffolds; 2) design and manufacture porous scaffolds suitable for bone regeneration in the biocompatible polymer PPF using the layered manufacturing technology stereolithography (SL); and 3) render the PPF porous scaffolds bioactive.The first section of this study will focus on the design and manufacture of a perfusion bioreactor with interchangeable cassettes suitable for the location of custom designed scaffolds. PPF will be synthesized with molecular weights of 800-1,000 Da and 1,800-2,000 Da following previously published procedures. Three-dimensional CAD will be used to design custom porous scaffolds with accurately controlled external and internal highly porous, interconnected architecture. Scaffolds will be manufactured using stereolithography, seeded with rat MSCs, and incubated in perfusion bioreactors for 4, 8 and 12 days. The degree of bioactivity will be determined by ELISA protein assays, and degree of calcium deposition. This research will develop manufacturing and biological strategies to produce bioactive patient-specific scaffolds for the repair of maxiliofacial bone defects.