Multivalent Nano-conjugates for Targeted Penetration of and Delivery to Dense Extracellular Matrices

尽管已经发现纳米颗粒在更传统的血管器官和 在缺乏血管系统辅助的组织中，纳米颗粒的运输面临着不同的挑战 穿透到组织中。在这里，我们提出了一种系统的方法来设计纳米材料系统 能够将药物深入渗透和输送到无血管组织中。拟议的工作将集中于 关于建立一整套材料设计概念，以增强进入和通过这些组织的传输基于 尺寸、电荷密度和呈现、靶向和动态材料化学。在目标1中，我们将发展 两个具有模块化设计的多价药物纳米载体家族，每个家族都具有独特的优势 用于组织穿透。然后将检查这些纳米载体的传输作为大小和电荷的函数 使用体外组织模型快速筛选纳米载体文库并确定最佳大小/电荷 感兴趣组织的特征。我们将研究三种独特的无血管组织类型的运输：软骨， 了解半月板和角膜在设计要求和最佳运输方面的异同 一系列无血管组织类型的特征。这一目标的进一步翻译预计将提供 关于如何在药物输送的背景下处理其他类似屏障组织的基本知识。 软骨的治疗对解决骨关节炎等疾病提出了特别重要的医学 挑战，是这些研究后来目标的疾病焦点；然而，成功地证明了 在第一个目标中，该系统将适用于其他组织和条件，包括向角膜和 关节半月板。为了实现更具组织响应性的递送方法，pH响应性和酶 可降解连接物将在目标2中用于治疗的结合，重点放在结合上 IGF-1是一种生长因子，可以促进早期骨关节炎的软骨再生。优化版本 的纳米载体将在体内进行研究，使用早期手术创伤大鼠模型来评估 使用不可降解、水解性和蛋白酶激活的可降解连接物治疗IGF-1的疗效 并测定体内实时药代动力学与游离IGF-1。将进行软骨治疗研究 在这种模式下，IGF-1的交付。最后，这项研究的另一个方面将是纳米结合物的设计 选择性地将药物释放到与不同纳米载体传输特性匹配的组织区域 在早期目标中确定，包括渗透程度和在组织中的停留时间。组合 地塞米松和TLR4抑制剂等小分子药物的治疗将与载体结合 最适合每种药物，与顶级IGF-1配方相结合。我们将评估其治疗效果。 通过测量炎症标志物，在细胞因子挑战体外软骨组织模型中的组合， 基质沉积和维持以及软骨修复的动力学。 1

Although nanoparticles have been found to be effective in delivery to more traditional vascularized organs and tissues, there are different challenges for nanoparticle transport in tissues that lack a vascular system to assist in penetration into the tissue. Here we propose a systematic approach to the design of nanomaterials systems that are capable of deep penetration and delivery of agents into avascular tissues. The proposed work will focus on establishing sets of materials design concepts to enhance transport into and through these tissues based on size, charge density and presentation, targeting and dynamic materials chemistries. In the Aim 1, we will develop two promising families of multivalent drug nanocarriers with modular design, each presenting unique advantages for tissue penetration. The transport of these nanocarriers will then be examined as a function of size and charge using ex vivo tissue models to rapidly screen libraries of nanocarriers and identify optimal size/charge characteristics for tissues of interest. We will examine transport in three unique avascular tissue types: cartilage, meniscus and cornea to understand similarities or differences in design requirements and optimal transport characteristics for a range of avascular tissue types. Further translation of this Aim is anticipated to provide fundamental knowledge regarding how to address other similar barrier tissues in the context of drug delivery. Treatment of cartilage to address conditions such as osteoarthritis presents a particularly important medical challenge, and is the disease focus for the later Aims of these studies; however, successful demonstration of this system in the first Aim will be applicable to other tissues and conditions, including delivery to the cornea and joint meniscus. To enable a more tissue-responsive delivery approach, both pH responsive and enzyme degradable linkers will be examined in Aim 2 for the conjugation of therapeutics, with the focus on conjugation of IGF-1, a growth factor that can facilitate cartilage regeneration in early stage osteoarthritis. Optimized versions of the nanocarriers will be studied in an established in vivo using an early surgical trauma rat model to evaluate the efficacy of IGF-1 treatments with the nondegradable, hydrolytic, and protease-activated degradable linkers and determine in vivo real-time pharmacokinetics versus free IGF-1. Cartilage treatment studies will be carried out in this model for IGF-1 delivery. Finally, an additional aspect of this study will be the design of nanoconjugates that release drug selectively to regions of tissue matched to the different nanocarrier transport properties determined in earlier Aims, including degree of penetration and residence time within the tissue. Combination treatments for small molecule drugs including dexamethasone and TLR4 inhibitors will be conjugated to carriers optimal for each drug, in combination with the top IGF-1 formulation. We will evaluate the therapeutic effects of the combinations in a cytokine-challenged ex vivo cartilage tissue model by measuring inflammatory markers, matrix deposition and maintenance, and kinetics of cartilage repair. 1