효소촉매를 이용한 주입형 카파 카라기난 하이드로젤의 합성 및 특성분석
enzyme mediated in situ forming kappa-carrageenan based hydrogels ; synthesis and characterizations
- 주제(키워드) Injectable hydrogels , Kappa-carrageenan , Thermo-reversible , Horseradish peroxidase (HRP) , Oxidation
- 발행기관 아주대학교
- 지도교수 박기동
- 발행년도 2019
- 학위수여년월 2019. 2
- 학위명 석사
- 학과 및 전공 일반대학원 분자과학기술학과
- 실제URI http://www.dcollection.net/handler/ajou/000000028339
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
Carrageenans (CGs) are hydrophilic, linear sulfated polysaccharides extracted from red algae. CGs have been utilized for tissue engineering due to their biocompatibility, non-toxic nature, and excellent physical properties. However, CGs form helical structures, which give them a gel-formation ability; hence, most CG hydrogels are thermoreversible and prepared using ion-crosslinking methods. Because these hydrogels cannot carry heat-sensitive drugs, growth factors, and cells, their in vivo application is limited. To solve these problems, an enzymatic crosslinking method to prepare CG hydrogels was introduced. Injectable hydrogels can seal wounds with minimal invasion and be crosslinked under mild conditions. In this study, an in-situ enzymatic crosslinking method based on horseradish peroxidase (HRP)-mediated reactions with hydrogen peroxide was utilized to synthesize CG-based hydrogels. We first prepared kappa-carrageenan poly (ethylene glycol)-tyramine (ka-CGPT) conjugates. Firstly, PNC-PEG-PNC was conjugated with tyramine (TA) via a urethane bond. Secondly, NH2 was conjugated with PNC-PEG-TA. Thirdly, oxidized carrageenan was conjugated with NH2-PEG-TA by EDC/NHS coupling chemistry. The CGPT conjugates were then used to prepare hydrogels via horseradish peroxidase (HRP)-mediated reactions in the presence of hydrogen peroxide. The gelation time was controlled from 5 sec to 5 min with various concentrations of HRP (0.1–0.5 mg/ml). It was found that the hydrogen peroxide concentration (0.3–0.7 wt%) can control the mechanical strength (150–700 Pa) of the hydrogels. In vitro 2D cell viability studies demonstrated that the ka-CGPT hydrogels had excellent bioactivity. Such modified injectable hydrogel platforms are promising materials and will be utilized for various tissue engineering strategies.
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CONTENTS
1. INTRODUCTION ……………………………………………………………………………… 1
1.1 Tissue engineering approach of biomaterials ……………………………………… 1
1.2 Hydrogels as biological material ……………………………………………………… 3
1.2.1 Injectable hydrogels …………………………………………………………………… 4
1.2.1.1 Physical crosslinking ………………………………………………………………… 4
1.2.1.2 Chemical crosslinking .................................................................... 5
1.2.1.3 Enzyme-mediated crosslinking ……………………………………………… 5
1.2.2 Mechanism for HRP enzymatic cross-linking method …………………… 6
1.3 Origin and application of Carrageenan natural polymer …………………… 7
1.3.1 Properties and characteristics of carrageenan …………………………… 9
1.4 Objectives …………………………………………………………………………… 10
2. EXPERIMENTS ……………………………………………………………………… 12
2.1 Materials …………………………………………………………………………… 12
2.2 Synthesis of ka-CG natural polymers………………………………………… 13
2.2.1 Synthetic process of oxidized Kappa-carrageenan ……………………… 13
2.2.2 Synthetic process of amine reactive PEG derivatives …………………… 14
2.2.3 Synthesis of Kappa-carrageenan-PEG-TA (ka-CGPT) …………………… 16
2.3 Quantification of oxidized ka-CG ……………………………………………… 16
2.4 Characterization of chemical structure of oxidized ka-CG and ka-CGPT ……………………………………………………………………………………………… 18
2.5 Preparation of ka-CGPT hydrogels …………………………………………… 19
2.6 Characterization of ka-CGPT hydrogels ……………………………………… 19
2.6.1 Measuring of gel formation time …………………………………………… 19
2.6.2 Rheological study ……………………………………………………………… 19
2.7 Thermogravimetric analysis (TGA) …………………………………………… 20
2.8 In vitro 2D cell viability test of ka-CGPT hydrogels ………………………… 20
3. RESULTS AND DISCUSSIONS ……………………………………………………… 21
3.1 Synthesis and characterizations of ka-CGPT polymer ……………………… 21
3.2 Chemical structure of ka-CG and ka-CGPT …………………………………… 22
3.3 Controllable hydrogel formation time and rheological properties ……… 24
3.3.1 Preparation of ka-CGPT hydrogels …………………………………………… 24
3.3.2 The controlled gelation time of ka-CGPT hydrogels ……………………… 25
3.3.3 Rheological analysis of ka-CGPT hydrogels by varying hydrogen peroxide concentration ………………………………………………………………………………………………… 26
3.4 Thermal gravimetric analysis (TGA) of ka-CGPT ……………………………… 27
3.5 In vitro 2D cell viability test of ka-CGPT hydrogels …………………………… 28
4. CONCLUSION ………………………………………………………………………… 30
5. REFERENCE …………………………………………………………………………… 31
6. 국문 초록 .............................................................................................. 34
