Fibrin-Based Nanoparticles as a Novel Sealant for Vascular Anastomosis

项目总结 血管吻合术是一种重要的外科技术，通过紧密缝合来连接血管。 这一过程经常用于器官移植、创伤修复和心血管手术。然而，血管 吻合术耗时长，并发症严重，恢复时间长。纤维蛋白胶在手术中的应用 吻合术改善了手术结果，缩短了手术时间，但这些胶水往往不切实际。 因为它们的浓缩配方产生了工作时间短、细胞渗透率低、温度低的高密度凝胶 存储限制。我们已经开发了基于纤维蛋白的纳米颗粒(FBN)，我们已经使用它来输送生长因子 并促进体内愈合。与传统的纤维蛋白胶不同，FBN是预先聚合的，并使用生理上相关的 纤维蛋白/凝血酶浓度。由于它们的胶体结构和上述性质，FBN显示出可调的 凝胶，增加细胞渗透，室温储存和增强的药物输送能力-包括 成纤维细胞生长因子2(FGF2)，一种已知的血管修复刺激剂。这项建议的目标是优化， 一种生长可调的FBN外科密封剂的可涂覆和贴片配方的表征和体内分析 因子释放。预计这些FBN密封剂将显示出比目前的纤维蛋白胶更好的功能， 更长的工作时间、更长的室温稳定性、靶向生长因子传递和改进的优势 治愈的结果。目标1将优化贴片和流动FBN胶的配方。这将通过以下方式实现 FBN浓度、凝血酶浓度和使用的辅因子的变化对 胶水的机械和功能。测试将探测聚合和降解动力学、结构、 机械性能、密封剂能力和安全配置。使用的方法包括流变仪、显微镜、机械 测试，以及新的体外和微流控检测。目标2将优化FBN和FGF2的加载/释放 研究FGF2-FBN封闭剂对血管创面愈合的影响。FGF2装载效率和释放 将测定FBN密封胶的特性，并将其与高密度散装纤维蛋白胶进行比较。内皮细胞和成纤维细胞 划痕试验和伤口闭合试验将用于评估体外愈合结果。AIM 3将比较FBN 使用来宝林体内模型将制剂(凝胶和贴片；卸载和加载FGF2)添加到当前的纤维蛋白胶中 颈动脉吻合术。血管造影术将用于表征取样组织的血管形态和组织学 将被用来评估愈合、再狭窄和增生的迹象。这项提议使用FBN将导致一种新的 手术密封胶具有更长的工作时间和可调的给药方案，具有卓越的伤口愈合能力 更快的操作时间、更少的并发症和更好的恢复。这项技术还将增加可访问性 通过消除冷链要求，使其在各种全球健康应用中得以广泛使用，外科手术胶得到了广泛的应用。培训 此项目所需的相关研究技术和临床技能将有助于申请者的成功 在她职业生涯的下一个阶段，在成为一名独立的内科科学家的道路上。

PROJECT SUMMARY Vascular anastomosis is an important surgical technique whereby closely spaced stitches are used to connect blood vessels. This process is used frequently in organ transplantation, trauma repairs, and cardiovascular surgery. However, vascular anastomosis is time consuming and associated with serious complications and long recovery times. Use of fibrin glue in anastomosis has led to improved surgical outcomes and shorter operating times, but these glues are frequently impractical as their concentrated formulations create high-density gels with short working times, low cellular infiltration, and cold storage limitations. We have developed fibrin-based nanoparticles (FBNs) which we have used to deliver growth factors and promote healing in vivo. Unlike traditional fibrin glues, FBNs are pre-polymerized and use physiologically relevant fibrin/thrombin concentrations. Owing to their colloidal structure and the aforementioned properties, FBNs exhibit tunable gelation, increased cellular infiltration, room temperature storage, and enhanced drug delivery capabilities – including of fibroblast growth factor 2 (FGF2), a known stimulant of vascular repair. The objective of this proposal is the optimization, characterization and in vivo analysis of paintable and patch formulations of an FBN surgical sealant with tunable growth factor release. It is expected that these FBN sealants will demonstrate better functionality than current fibrin glues, with the benefit of longer work time, extended stability at room temperature, targeted growth factor delivery, and improved healing outcomes. Aim 1 will optimize the formulation of patch and flowable FBN glues. This will occur through characterization of the effects of changes in FBN concentration, thrombin concentration, and cofactor used, on the mechanics and functionality of the glues. Testing will probe polymerization and degradation dynamics, structure, mechanical properties, sealant ability, and safety profile. Modalities used will include rheometry, microscopy, mechanical testing, and novel ex vivo and microfluidic assays. Aim 2 will optimize the loading/release of FGF2 by FBNs and characterize the effects of FGF2-FBN sealants on vascular wound healing in vitro. FGF2 loading efficiency and release characteristics of FBN sealants will be determined and compared to high-density bulk fibrin glues. Endothelial and fibroblast scratch tests and wound closure assays will be used to assess healing outcomes in vitro. Aim 3 will compare FBN formulations (gel and patch; unloaded and loaded with FGF2) to current fibrin glues using an in vivo leporine model of carotid artery anastomosis. Angiography will be use to characterize vascular morphology and histology of sampled tissues will be used to evaluate signs of healing, restenosis, and hyperplasia. This proposal’s use of FBNs will lead to a novel surgical sealant with improved work time and tunable drug delivery profiles that boasts superior wound healing – allowing for faster operating times, fewer complications, and improved recovery. This technology will also increase the accessibility of surgical glues by removing cold-chain requirements, opening up their use in varied global health applications. Training in the associated research techniques and clinical skills required for this project will contribute to the success of the applicant during the next phases of her career on the path to becoming an independent physician scientist.