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不含溶剂、微粒和聚合引发剂的工艺再生患者特定颞下颌关节（TMJ）髁突。在更广泛的意义上，该技术可以容易地应用于矫形应用或具有复杂宏观形状要求的任何其他组织工程应用。然而，由于颞下颌关节一直被明显排除在骨科界的进步，并与严重折磨颞下颌关节患者的痛苦和绝望，我们选择了颞下颌关节作为我们的注意力的优先重点。实现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，本提案的目的将是使用一种新的干细胞源与超临界流体方法一起以预定形状工程化骨。由于加压的CO2在环境温度下熔化聚（乳酸-乙醇酸共聚物）（PLGA），PLGA随着压力的释放而膨胀，CO2逸出，就像香槟在摇晃的瓶子上弹出软木塞时一样，除了PLGA泡沫在压力释放时固化。我们假设我们可以利用这种现象，让PLGA膨胀到模具中，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，介绍了CO2发泡的新应用：作为在组织工程中生产形状特异性支架的替代方法。我们的总体策略是将人脐带基质干细胞（HUCMSCs）暴露于髁状突形状的泡沫PLGA支架中的成骨因子。我们的主要假设是，骨诱导HUCM干细胞，结合一种新的超临界流体支架发泡方法，将导致一个特定形状的工程化颞下颌关节髁突。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泡沫聚（乳酸-羟基乙酸）（PLGA）支架工程骨栓，3）工程特定形状的TMJ髁突骨结构。拟议的研究通过利用令人兴奋的新细胞来源，并将现有技术（支架发泡）作为创建形状特异性支架的新方法，为肌肉骨骼组织工程提供了一种创新方法。该应用最终将成为转化研究的逻辑候选者，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图像中创建患者特异性模具，HUCMSC可从脐带细胞库中获得，甚至可以从患者自己的冻存HUCMSC中获得。实现我们的长期目标将彻底改变TMJ治疗，恢复被疾病破坏的TMJ的结构和功能（例如，关节炎、癌症）和创伤，并为数百万患有颞下颌关节紊乱症的美国人带来希望。 公共卫生相关性：颞下颌关节（TMJ）疾病，通常被称为颌关节，影响超过1000万美国人，导致痛苦的疼痛和简单活动的困难，如吃饭，说话和打哈欠。一个令人兴奋的潜在解决方案是组织工程，其目的是取代创伤和疾病破坏的TMJ结构。这项研究计划描述了一种环境友好的新方法，以再生解剖正确的颞下颌关节结构。

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.