Injectable and Bioadhesive Chitosan-based Hydrogels for Wound Management
창상 관리를 위한 조직접착성 주입형 키토산 하이드로젤에 관한 연구
- 주제(키워드) in situ hydrogel , tissue adhesive , wound management , tissue engineering , chitosan , PEG
- 발행기관 아주대학교
- 지도교수 박기동
- 발행년도 2013
- 학위수여년월 2013. 2
- 학위명 박사
- 학과 및 전공 일반대학원 분자과학기술학과
- 실제URI http://www.dcollection.net/handler/ajou/000000014254
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
Tissue adhesives have attracted and rapidly growing interest as sealants, hemostatic agents, and non-invasive wound-closure devices. The adhesives are required to perform a variety of functions including sealing leaks, stop bleeding, binding tissues, and preferably facilitating a healing process. Chitosan, a cationic polysaccharide, has been used as a wound dressing material due to its superior tissue- or mucoadhesive property, hemostatic activity, low toxicity, relevant biodegradability, and anti-infection activity. Despite the advantages, the rigid crystalline structure of chitosan makes it hard to be dissolved in water, which has partially retarded its potential for the application. Recently, the enzymatic reaction using horseradish peroxidase (HRP) and hydrogen peroxide (H2O2) has received much attention as an alternative method for preparing in situ forming hydrogels due to their mild condition. The enzymatically crosslinked hydrogels showed excellent bioactivities and tunable physicochemical properties, suggesting that this type of hydrogels have great potential for use as injectable materials for tissue regenerative medicine and various biomedical applications. The objectives of this dissertation are to develop in situ cross-linkable chitosan and poly(ethylene glycol) (PEG)-based hydrogels as an injectable matrix via HRP-mediated crosslinking reaction for wound management. For the study, hydroxyphenylacetic acid conjugated chitosan (CHPA), chitosan-poly(ethylene glycol)-tyramine (CPT), tyramine conjugated 4-arm-poly(propylene oxide)-poly(ethylene oxide) (TTA) and gelatin-poly(ethylene glycol)-tyramine (GPT) polymers were synthesized and characterized. The hydrogels were rapidly formed via HRP-mediated crosslinking reaction under physiological condition. Their physico-chemical properties such as gelation time, mechanical strength, adhesive strength and degradation rate could be controlled easily by varying the concentrations of polymer, HRP and H2O2. In the cytocompatibility study, the encapsulated fibroblasts showed a high viability in the hydrogels via enzyme-mediated crosslinking process. The chitosan-based hydrogels were cured either on a mouse liver defect or in rat skin incision models within 5 s showing excellent hemostatic properties and wound healing effects. The in vitro and in vivo degradation studies of chitosan and gelatin mixed hydrogels showed that the hydrogels had enormous potential for a broad range of applications from surgical devices to cell supporting scaffolds onto various defects with different concentrations of lysozyme and collagenase. Obtained results demonstrated that the in situ cross-linkable chitosan and PEG-based hydrogels, with excellent bioactivities and multi-tunable properties, have great potential for use as injectable materials in surgical applications including tissue regeneration and drug delivery.
more목차
Abstract i
Table of Contents iv
List of Figures viii
List of Tables xiii
1. General Introduction
1.1. Background 2
1.1.1. Wound healing 3
1.1.2. Requirements of wound closure 7
1.2. Surgical incision closures 9
1.2.1. Suture 10
1.2.2. Staple 12
1.2.3. Tape 13
1.2.4. Hemostat 14
1.2.5. Anti-adhesion 16
1.2.6. Sealant 18
1.2.7. Glue/Adhesive 18
1.3. Polymeric materials for tissue adhesive 19
1.3.1. Fibrinogen 21
1.3.2. Cyanoacrylate 25
1.3.3. Collagen 27
1.3.4. Albumin 28
1.3.5. Poly(ethylene glycol) 29
1.4. Hydrogels and chitosan for wound management 30
1.4.1. General features of hydrogel 30
1.4.2. Chitosan 33
1.4.3. Chitosan-based hydrogels for tissue adhesives 35
1.5. Overall objectives 38
2. Preparation of chitosan-based hydrogels
2.1. Materials 40
2.2. Synthesis of phenol-conjugated polymers 41
2.2.1. Chitosan-hydroxyphenylacetic acid (CHPA) 41
2.2.2. Chitosan-poly(ethylene glycol-tyramine conjugates (CPT) 43
2.2.3. Tyramine terminated 4-arm PPO-PEO (TTA) 46
2.2.4. Gelatin-poly(ethylene glycol)-tyramine conjugates (GPT) 48
2.3. Preparation of hydrogels 50
2.3.1. CHPA/TTA hydrogel 50
2.3.2. CPT hydrogel 50
2.3.3. CPT/GPT hydrogel 51
2.4. Characterizations 53
2.4.1. Polymer characterizations 53
2.4.2. Determination of gelation time 54
2.4.3. Rheological experiment 54
2.4.4. Measurement of tissue adhesive strength 55
2.4.5. Evaluation of in vitro degradation 57
2.5. In vitro cell culture 58
2.5.1. Cell viability 58
2.5.2. Cytotoxicity 58
2.6. In vivo animal study 59
2.6.1. Degradability 59
2.6.2. Tissue adhesiveness 60
2.6.3. Hemostatic ability 60
2.6.4. Animal experiment for wound closure 61
3. Results and discussions
3.1. Polymer characterizations 64
3.1.1. Chemical structure of conjugates 64
3.1.2. Quantitative analysis of conjugated phenol group 71
3.1.3. Compositional analysis of conjugates 72
3.2. Hydrogel characterizations 72
3.2.1. Hydrogel formation and gelation time 72
3.2.2. Controllable mechanical properties 81
3.2.3. Tunable tissue adhesive properties 86
3.2.4. In vitro proteolytic degradability 92
3.3. Cytocompatibility 96
3.4. Animal study 100
3.4.1. Tissue adhesiveness 100
3.4.2. Hemostatic property 101
3.4.3. Wound closing and healing effect 102
3.4.4. In vivo degradation behavior 108
4. Conclusions 111
5. References 114
Abstract in Korean 127
