Novel Biomaterials as Sealants for Applications in Annulus Fibrosus Repair

描述（由申请人提供）：腰痛通常与椎间盘退变（IVD）有关，是患者就诊时最常见的身体状况。目前还没有可接受的生物材料可用于修复IVD的小纤维环（AF）缺陷，这些缺陷可能与针头注射生物制剂或椎间盘造影术、椎间盘切除术治疗突出或其他小病变和AF撕裂有关。这些类型的缺陷与IVD加速变性有关。本培训经费的总体目标是评估与小型AF修复中有前途的生物材料密封剂开发相关的基础生物力学和生物学。用于AF修复的密封胶的成功取决于其机械性能、细胞相容性及其在原位复杂机械和化学环境中的功能。这项培训经费包括AF组织密封剂的力学和生物学评估，以及它们与天然AF组织的相互作用，以优化体外生物材料并评估原位生物材料。有效的AF密封剂必须设计成具有可调的材料特性，促进细胞浸润，具有强粘合能力，并且可注射以填补各种缺陷。提出的两种凝胶是根尼平交联纤维蛋白凝胶（fiber -gen）和羧甲基纤维素水凝胶（CMC）。体外优化（Aim 1）包括在剪切中测试每种凝胶的多种密封剂配方，以匹配天然牛心房纤维组织的机械刚度，在与天然牛心房纤维组织的双层结构中产生强粘合性能，并促进细胞活力和细胞增殖。原位评估（Aim 2）是使用一种新型的共聚焦显微镜成像技术在微观水平上评估载荷下的密封-组织界面，评估修复后椎体运动节段双轴力学特性的机械修复，并使用器官培养技术评估密封-组织界面对细胞生长和运输的影响。总的假设是，AF粘合密封剂可以优化为细胞相容性，具有与天然AF组织相当的机械强度，并且能够将受伤运动节段的生物力学行为恢复到未受伤状态。该研究策略的拟议目标补充了由培训模块组成的培训计划，包括生物材料表征和开发（CMC和纤维原配方），细胞和分子生物学（细胞活力和增殖测试），显微镜和成像（微尺度成像和粘接剂和组织界面的应变映射），以及临床和转化研究（临床相关缺陷的应用和修复交付）。

DESCRIPTION (provided by applicant): Low back pain is often associated with degeneration of the intervertebral disc (IVD) and represents the most common physical condition for which patients visit their doctor. There are currently no acceptable biomaterials available to repair small annulus fibrosus (AF) defects of the IVD that might be associated with needle injection of biologics or discography, discectomy procedures for herniations, or other small lesions and AF tears. These types of defects are linked with accelerated IVD degeneration. The overall goal of this training grant is to evaluate fundamental biomechanics and biology associated with the development of promising biomaterial sealants for small AF repairs. The success of a sealant for AF repair depends on its mechanical properties, cytocompatibility, and its ability to function in a complex mechanical and chemical environment in situ. This training grant involves mechanical and biological assessments of AF tissue sealants and their interactions with native AF tissue in order to optimize the biomaterial in vitro and to evaluate the biomaterial in situ. Effective AF sealants must be designed to have tunable material properties, promote cell infiltration, have strong adhesive capabilities, and be injectable to fill a variable range of defets. The two gels proposed are a genipin cross- linked fibrin gel (fib-gen) and carboxymethylcellulose hydrogel (CMC). The in vitro optimization (Aim 1) is comprised of testing multiple sealant formulations of each gel in shear to match the mechanical stiffness of native bovine AF tissue, to create strong adhesive properties in bilayered constructs with native bovine AF, and to promote cell viability and cell proliferation on cell-seeded gels. The in situ assessments (Aim 2) are to assess the sealant-tissue interface at the microscale level using a novel confocal microscopy imaging technique under loading, to evaluate mechanical restoration of biaxial mechanical properties in a vertebral motion segment following repair, and to assess the sealant-tissue interface for cell growth and transport using organ culture techniques. The overall hypothesis is that an AF adhesive sealant can be optimized to be cytocompatible, of comparable mechanical strength as native AF tissue, and capable of restoring biomechanical behaviors of injured motion segments to the uninjured state. The proposed aims of this research strategy complement a training plan comprised of training modules that include Biomaterials Characterization and Development (with CMC and fib-gen formulation), Cell and Molecular Biology (with cell viability and proliferation testing), Microscopy and Imaging (with microscale imaging and strain mapping of adhesive and tissue interfaces), and Clinical and Translational Research (with application of clinically relevant defects and delivery of repair). PUBLIC HEALTH RELEVANCE: Intervertebral disc degeneration is thought to play a major role in the manifestation of low back pain. This training grant will develop, optimize and evaluate novel hydrogel biomaterials for their use as sealants to be used in minimally invasive surgical interventions for pathological conditions of the IVD. Training goals that complement the scientific aims allow the applicant to develop novel and important new technical skills that expand and build off her prior biomedical engineering background to prepare her for an independent research career.