헤파린 및 펩타이드가 고정화된 폴리우레탄의 심혈관계 응용에 관한 연구
Heparin and peptides co-immobilized polyurethane surfaces for cardiovascular application
- 주제(키워드) heparin , YIGSR , RGD , Polyurethane
- 주제(KDC) 570
- 주제(DDC) 660
- 발행기관 아주대학교
- 지도교수 박기동
- 발행년도 2007
- 학위수여년월 2007. 8
- 학위명 석사
- 학과 및 전공 일반대학원 분자과학기술학과
- 본문언어 영어
초록/요약
Polyurethane (PU) is widely used as cardiovascular biomaterials due to its mechanical properties and good biocompatibility but the inherent blood compatibility of PU itself is not enough for more widespread application. Heparin, a representative anticoagulant, is clinically well used and is known to promote endothelialization through complexation with VEGF or bFGF as a growth factor, which are effective to proliferation and differentiation of endothelial cells. Peptides like YIGSR and RGD were also found to promote adhesion and spreading ECs and show the synergistic effect when both of them were used. The PU (Polycarbonate urethane, Bionate 90A) matrices were fabricated by the electrospinning process and modified with diisocyanate PEG (polyethylene glycol, 1.0K). Then, heparin was covalently bound onto PU-PEG surface. The peptides (RGD and YIGSR) were immobilized onto aminated PU-PEG surface by EDC/NHS method. The content and the bioactivity of bound heparin were analyzed by toluidine blue assay and factor Xa chromogenic assay, respectively. The immobilized peptides were confirmed by amino acid analysis, following hydrolysis. Surface properties of the modified PU were characterized by SEM, AFM and static contact angle. In vitro fibrinogen adsorption and platelet adhesion test of the bound heparin were carried out. To evaluate EC adhesive property, HUVEC attachment and proliferation tests were investigated in vitro. Finally, in vivo endothelialization of the bioactive PU matrices was characterized using a canine model. Our results represented that PU matrices were successfully modified with heparin and peptides for improved endothelialization. These bioactive PU matrices revealed higher HUVEC activities than unmodified PUs in vitro and in vivo. Therefore, hepain/peptide co-immobilized PU surfaces can be applied to EC-specific matrices, including new cardiovascular applications with long-term patency.
more목차
Ⅰ. INTRODUCTION 1
A. Theoretical background 1
1. Biomaterial-body interaction at biointerface 1
2. Polyurethane (as polymeric biomaterials) 4
3. Surface modifications for improved biocompatibility 8
3.1. Heparin 8
3.2. Cell adhesive peptides (RGD, YIGSR) 16
B. Objectives 19
Ⅱ. EXPERIMENTS 20
A. Materials 20
B. Fabrication of PU films 21
C. PEG grafting onto PU surfaces 22
D. Heparin immobilization onto PU surfaces 22
E. Peptides modification onto PU surfaces 26
F. Surface analysis of polymer blend film 28
1. SEM and AFM 28
2. Contact angle measurement 29
G. In vitro blood compatibility 31
1. Factor Xa assay 31
2. Protein adsorption of modified PUs 32
3. In vitro platelet adhesion to polymer surfaces 33
H. In vitro cell compatibility 34
I. Fabrication of PU tubes using electrospinning 35
J. In vivo animal test 36
Ⅲ. RESULTS AND DISCUSSION 38
A. Analysis of bioactive agents modified PU surfaces 38
B. Surface hydrophilicity; Contact angle 42
C. Activity test of heparin 44
D. In vitro blood compatibility test 46
E. In vitro HUVEC attachment & proliferation 49
F. SEM images of PU tubes 53
G. In vivo animal test 54
Ⅳ. CONCLUSIONS 56
Ⅴ. REFERENCES 57
