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

描述(申请人提供)：这项申请的长期目标是使用一种不含溶剂、微粒和聚合引发剂的方法再生患者特定的颞下颌关节(TMJ)髁状突。在更广泛的意义上，这项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TMJ明显地被排除在骨科社区的进步之外，而且TMJ患者遭受着痛苦和绝望的严重折磨，我们选择了TMJ作为我们关注的优先焦点。迈向我们长期目标的第一步将是开发一种新型的髁状突形状的骨结构。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将骨工程化为预定的形状。由于加压的二氧化碳在常温下会熔化聚(乳酸-乙醇酸)(PLGA)，因此PLGA会随着压力的释放而膨胀，而二氧化碳会逸出，就像香槟在摇动的瓶子上打开软木塞时所做的那样，只是PLGA泡沫在释放压力时会凝固。我们假设，我们可以利用这一现象，允许PLGA膨胀成一个模具，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。我们在这项建议中的总体策略是将人脐带基质干细胞(HUCMSCs)暴露在一种髁突形状的泡沫PLGA支架中，使其暴露于成骨因子中。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发泡方法，将导致特定形状的工程化TMJ关节突。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)利用CO2发泡的聚乳酸-乙醇酸(PLGA)支架设计骨塞；3)设计一种特定形状的TMJ髁状突骨结构。这项拟议的研究提出了一系列肌肉骨骼组织工程的创新方法，通过利用令人兴奋的新细胞来源，并将现有技术(支架发泡)作为一种新的方法来创建特定形状的支架。这种应用最终将成为转化研究的合理候选者，拥有人类细胞来源，FDA批准的生物材料，以及环境友好、成本效益高的制造工艺。长期的愿景是从CT图像中创建特定于患者的模具，从脐带细胞库中获得HUCMSC，或者甚至可以从患者自己的冷冻保存的HUCMSC中获得。实现我们的长期目标将彻底改变TMJ的治疗方法，恢复饱受疾病(如关节炎、癌症)和创伤蹂躏的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。 公共卫生相关性：颞下颌关节(TMJ)疾病，俗称颌关节，影响着1000多万美国人，导致进食、说话和打哈欠等简单活动中的剧痛和困难。一个令人兴奋的潜在解决方案是组织工程学，其目标是取代因创伤和疾病而遭到破坏的TMJ结构。这项研究计划描述了一种环境友好的新方法来再生解剖上正确的TMJ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.