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基于肝素分子固定与原位催化释放NO的仿生支架表面构筑

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目录

声明

摘要

Abstract

Table of Contents

Chapter 1 Introduction

1.1.1 Cardiovascular disease,atherosclerosis

1.1.2 Coronary artery bypass graft surgery and vascular grafts

1.1.3 Percutaneous coronary intervention and coronary artery stents

1.2 Endothelium function mimicking surface modification

1.2.1 ECs functions

1.2.2 Heparin based surface modification

1.2.3 Nitric oxide based surface modification

1.3 Progress of Polydopamine Coating in Biomedical Field

1.3.1 Coating mechanism,structure and preparation

1.3.2 Applications in biomedical field

1.4 Significance and Objectives,Dissertation Layout and Technical route

1.4.1 Significance and objectives

1.4.2 Dissertation layout

1.4.3 Technical route

Chapter 2 Mussel-inspired Chemistry for Biocompatible and Functional Coatings Rich in Amine groups

2.1 Introduction

2.2 Experimental Section

2.2.2 Characterization of the PDAM/HD copolymet coating

2.2.3 HUVEC culture,staining and proliferation

2.2.4 Macrophages evaluation and in vivo tissue response test

2.2.5 Heparin conjugation and quantitative determination

2.2.6 APTT assay

2.2.7 Statistical analysis

2.3 Results analysis

2.3.1 FTIR,amine group density and thickness of PDAM/HD coating

2.3.2 XPS,SIMS results

2.3.3 AFM and WCA results

2.3.4 Mechanical behavior and stability

2.3.5 Adhesion,proliferation and staining of endothelium cell

2.3.6 Macrophages evaluation and tissue response

2.3.7 Conjugation of heparin and bioactivity assay

2.4 Discussion

2.5 Conclusion

Chapter 3 Heparinized Mussel-inspired Coating Baring Amine Group for Multi-Functionalization of Vascular Stent

3.1 Introduction

3.2 Experimental Section

3.2.1 Preparation of PDAM/HD coating

3.2.2 Characterization of PDAM/HD coating

3.2.3 Heparin conjugation and quantification

3.2.4 Hemocompatibility evaluation

3.2.5 Endothelium cell evaluation

3.2.6 Smooth muscle cell evaluation

3.2.6 Competitive Adhesion of ECs and SMCs

3.2.7 In vivo Subcutaneous Implantation Studies

3.2.8 Statistical analysis

3.3 Results analysis

3.2.1 Characterization of Hep-PDAM/HD

3.3.2 Hemocompatibility evalution

3.3.3 Endothelial cell evalution

3.3.4 Smooth muscle eell evalution

3.3.5 Competitive Adhesion of ECs and SMCs

3.3.6 In vivo Subcutaneous Implantation Studies

3.4 Discussion

3.5 Conclusion

Chapter 4 Biomimetic Design of NO-Generating Coatings for Improving the Performance of Vascular Stent

4.1 Introduction

4.2 Experimental Section

4.2.1 Preparation of PDAM/HD Coating

4.2.2 S-S and Se-Se Conjugation

4.2.3 Preparation of PDAM@Cu coatings

4.2.4 Characterization ofthe Coatings

4.2.5 NO Catalytic Release

4.2.6 Hemocomoatibility Evaluation

4.2.7 Smooth muscle cell evaluation

4.2.8 Endothelium cell evaluation

4.2.9 Macrophage evaluation and In vivo animal tests

4.2.10 Statistical Analysis

4.3 Results and discussion

4.3.1 Characterization of S-S@PDAM/HD and Se-Se@PDAM/HD Coatings

4.3.2 NO Catalytic Release

4.3.3 Hemocompatibility Evaluation

4.3.4 Characterization of PDAM@Cu coatings

4.3.5 NO Catalytic Release

4.3.6 Hemocompatibility and enhanced cGMP expression

4.3.7 Endothelium cell evaluation

4.3.8 Marophage Evaluation and tissue response

4.4 Conclusion

Chapter 5 Summary and Outlook

5.1 Summary

5.2 Outlook

Acknowlegements

References

Abbreviation List

Scientific achievements

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摘要

支架介入术是临床治疗心血管疾病最常见的手段之一,创伤小、即刻效果显著、可有效维持血管的通畅率。在过去的几十年里,研究者们采取多种技术手段来提高血管支架的疗效,特别是药物洗脱支架的临床应用,显著降低了支架内再狭窄的发生率。但是晚期血栓和支架内再狭窄依然是限制其临床应用的两大并发症,因而要设计出符合临床要求的理想血管支架仍需不断探索。
  健康的内皮层是防止血栓形成的天然屏障,因此赋予支架表面正常的内皮功能是预防上述并发症最有效的方式。肝素是重要的糖胺聚糖,也是体内组织主要抗凝血剂-蛋白多糖硫酸乙酰肝素-的结构衍生物。内皮层的另一重要功能是合成信号分子NO。这种分子足心血管系统中的关键分子。因此,尝试构建基于肝素功能化与NO催化释放的内皮功能仿生支架涂层。
  针对金属支架表面缺乏反应性基团,难以实现生物分子固定的局限性,本论文在金属支架表面创新性地引入己二胺与多巴胺进行交联聚合,制备出新型胺基密度高度可控的粘附性聚合涂层,有助于后继生物分子的优化固定。并对新引入材料多巴胺/己二胺共聚涂层用于锚定生物活性分子和作为支架涂层应用的可行性进行探索。实验结果表明,该涂层与基底结合牢固,具有优异的稳定性,同时具备良好的内皮细胞相容性,满足支架涂层应用的基本前提和要求。
  借助多巴胺/己二胺共聚涂层的平台,利用化学耦合方法进行肝素分子的接枝。涂层表面肝素的固定量接近900ng/cm2,并维持了其生物活性。这可通过肝素化表面显著延长的凝血时间,大量减少的血小板粘附量以及有效阻碍纤维蛋白原变性得以证实。肝素化表面提供了选择性促进内皮细胞粘附、增值和迁移,同时却抑制平滑肌细胞粘附与增殖的微环境。皮下植入实验表明,与医用316L不锈钢相比,肝素化涂层引发的组织反应较小,炎症细胞浸润和肉芽组织形成得以抑制。
  基于多巴胺/己二胺共聚涂层,木文开发了两种制备NO催化涂层的方法。其一是在多巴胺/己二胺共聚涂层表面固定3,3-二硒二丙酸(Se-Se)和3,3-二磺酸二丙酸(S-S)这两种NO催化分子。其二是在多巴胺聚合时引入铜离子,通过简单的一步表面浸涂法即可制备出NO催化粘附涂层。两种方法制备的NO催化涂层均表现出连续催化RSNO产生NO的能力,获得了从2-12nmol/cm2/min高度可控的NO生成速率范围。并且证实所有NO催化涂层都可通过环鸟苷酸信号通路实现显著抑制血小板粘附、聚集和激活的性质。此外,铜基NO催化涂层可有效改善血液相容性,抑制平滑肌增生,同时可促进内皮细胞生长。
  综上,本文基于多巴胺/己二胺共聚涂层构筑内皮功能仿生表面,证明了通过引入多功能生物分子肝素和NO来构筑多功能血管支架平台的可行性。同时探索了涂层材料与血液、ECs、SMCs和炎症细胞的作用机制,这些研究结果为设计全新一代血管支架提供了有力的理论基础和技术支撑。

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