Solvent-free engineering of a shape-specific osteochondral TMJ condyle

描述（由申请人提供）：本申请的长期目标是使用无溶剂、颗粒和聚合引发剂的工艺再生患者特定的颞下颌关节（TMJ）髁突。从更广泛的意义上说，该技术可以很容易地应用于骨科应用或任何其他具有复杂宏观形状要求的组织工程应用。然而，由于TMJ明显被排除在骨科领域的进展之外，并且严重的TMJ患者处于痛苦和绝望之中，我们选择TMJ作为我们关注的优先焦点。我们长期目标的第一步将是开发一种新型髁状骨结构。因此，这项提议的目标将是使用一种新的干细胞来源和超临界流体方法来设计预定形状的骨骼。由于加压的二氧化碳在环境温度下融化了聚乳酸-羟基乙酸（PLGA），当压力释放时，PLGA膨胀，二氧化碳逸出，就像香槟在摇瓶时打开软木塞一样，只是PLGA泡沫在压力释放时凝固了。我们假设我们可以利用这一现象，允许PLGA扩展到模具中，使其在固化时具有预定的形状。事实上，我们的初步测试证实了这一假设，引入了二氧化碳发泡的新应用：作为组织工程中生产特定形状支架的替代方法。我们的总体策略是将人脐带基质干细胞（HUCMSCs）暴露于髁状泡沫PLGA支架中的成骨因子中。我们的主要假设是，骨诱导的HUCM干细胞，结合一种新的超临界流体支架泡沫方法，将产生形状特异性的工程TMJ髁。为了验证这一假设，我们提出了以下具体目标：1)开发和表征超临界CO2支架制造技术，2)使用CO2发泡聚乳酸-羟基乙酸（PLGA）支架设计骨塞，以及3)设计形状特定的TMJ髁骨结构。本研究通过利用令人兴奋的新细胞来源，将现有技术（支架发泡）在原有方向上作为一种创造形状特异性支架的新方法，为肌肉骨骼组织工程提供了多层次的创新方法。该应用程序最终将成为转化研究的逻辑候选，具有人类细胞来源，fda批准的生物材料，以及环保，成本效益高的制造工艺。长期的愿景是从CT图像中创建患者特定的模具，从脐带血细胞库中获得HUCMSCs，甚至可以想象从患者自己的冷冻保存的HUCMSCs中获得。实现我们的长期目标将彻底改变TMJ的治疗，恢复被疾病（如关节炎、癌症）和创伤破坏的TMJ的结构和功能，并为数百万患有TMJ疾病的美国人带来希望。

DESCRIPTION (provided by applicant): The long-term objective of this application is to regenerate a patient-specific temporomandibular joint (TMJ) condyle using a process free of solvents, particulates and polymerization initiators. In a broader sense, this technology can be readily applied to orthopaedic applications or any other tissue engineering application with complex macroscopic shape requirements. However, because the TMJ has been conspicuously excluded from the progress of the orthopaedic community, and with severely afflicted TMJ patients in agonizing pain and despair, we have selected the TMJ as the prioritized focus of our attention. The first step toward our long-term objective will be to develop a novel condyle-shaped bone construct. Therefore, the objective of this proposal will be to use a novel stem cell source together with a supercritical fluid approach to engineer bone in a predetermined shape. Since pressurized CO2 melts poly(lactic-co-glycolic acid) (PLGA) at ambient temperatures, PLGA expands as the pressure is released and CO2 escapes, as champagne does when the cork is popped on a shaken bottle, except the PLGA foam solidifies when the pressure is released. We hypothesized that we could take advantage of this phenomenon by allowing the PLGA to expand into a mold to give it a pre-determined shape when it solidified. Indeed, our preliminary testing confirmed this hypothesis, introducing a new application for CO2 foaming: as an alternative approach for producing shape-specific scaffolds in tissue engineering. Our overall strategy in this proposal is to expose human umbilical cord matrix stem cells (HUCMSCs) to osteogenic factors in a condyle-shaped, foamed PLGA scaffold. Our chief hypothesis is that osteo-induced HUCM stem cells, combined with a novel supercritical fluid scaffold foaming approach, will result in a shape-specific engineered TMJ condyle. To test this hypothesis, we propose the following specific aims: 1) to develop and characterize the supercritical CO2 scaffold fabrication technique, 2) to engineer bone plugs using CO2-foamed poly(lactic-co-glycolic acid) (PLGA) scaffolds, and 3) to engineer a shape-specific TMJ condyle bone construct. The proposed research presents a layering of innovative approaches to musculoskeletal tissue engineering by utilizing an exciting new cell source, and taking an existing technology (scaffold foaming) in an original direction as a new method to create shape-specific scaffolds. This application will ultimately be a logical candidate for translational research, with a human cell source, an FDA-approved biomaterial, and an environmentally friendly, cost-effective fabrication process. The long-term vision is for patient-specific molds to be created from CT images, with HUCMSCs available from a cord cell bank or conceivably even from the patient's own cryopreserved HUCMSCs. Realization of our long-term goal would revolutionize TMJ treatment, restoring structure and function to TMJs ravaged by disease (e.g., arthritis, cancer) and trauma, and bringing hope to the millions of Americans suffering from TMJ disorders. PUBLIC HEALTH RELEVANCE: Disorders of the temporomandibular joint (TMJ), commonly known as the jaw joint, affect more than 10 million Americans, causing agonizing pain and difficulty in simple activities such as eating, talking, and yawning. An exciting potential solution is tissue engineering, which aims to replace TMJ structures ravaged from trauma and disease. This research plan describes an environmentally benign and novel approach to regenerate anatomically correct TMJ structures.