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

尽管已经发现纳米颗粒在递送到更传统的血管化器官和移植器官中是有效的， 组织中，对于缺乏血管系统来辅助的组织中的纳米颗粒运输存在不同的挑战。 渗透到组织中。在这里，我们提出了一个系统的方法来设计纳米材料系统 其能够深度渗透并将药剂递送到无血管组织中。拟议的工作将侧重于 建立一套材料设计概念，以加强进入和通过这些组织的运输， 尺寸、电荷密度和呈现、靶向和动态材料化学。在目标1中，我们将开发 具有模块化设计的两个有前途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。然后将这些纳米载体的运输作为尺寸和电荷的函数进行检查 使用离体组织模型快速筛选纳米载体文库并鉴定最佳尺寸/电荷 感兴趣的组织的特征。我们将研究三种独特的无血管组织类型的运输：软骨， 半月板和角膜，以了解设计要求和最佳运输的相似性或差异 一系列无血管组织类型的特征。进一步翻译这一目标，预计将提供 关于如何在药物递送的背景下处理其他类似屏障组织的基本知识。 治疗软骨以解决诸如骨关节炎的病症呈现出特别重要的医疗效果。 挑战，并且是这些研究的后期目的的疾病焦点;然而， 第一个目标中的该系统将适用于其它组织和条件，包括输送到角膜， 关节半月板为了实现更组织响应性的递送方法，pH响应性和酶响应性递送方法都是有效的。 可降解接头将在目标2中检查用于治疗剂的缀合，重点是缀合 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 将在建立的体内使用早期手术创伤大鼠模型进行研究，以评估 用不可降解的、水解的和蛋白酶活化的可降解接头处理IGF-1的功效 并测定相对于游离IGF-1的体内实时药代动力学。将进行软骨素治疗研究， 用于IGF-1的输送。最后，本研究的另一个方面将是纳米缀合物的设计 其选择性地将药物释放到与不同的纳米载体运输性质相匹配的组织区域 在早期的目标中确定的，包括渗透程度和在组织内的停留时间。组合 包括地塞米松和TLR 4抑制剂在内的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制剂组合。我们将评估治疗效果， 通过测量炎症标记物， 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