| 학회 | 한국고분자학회 |
| 학술대회 | 2004년 가을 (10/08 ~ 10/09, 경북대학교) |
| 권호 | 29권 2호, p.222 |
| 발표분야 | 고분자 가공/블렌드 |
| 제목 | Preparation of Silk fibroin/Chitosan Conjugate crosslinked by Tyrosinase |
| 초록 | Introduction Silk fibroin (SF) and chitosan are well known as biocompatible polymers capable of being easily and largely accessible from nature. SF, a natural protein from Bombyx mori, is semicrystalline polymer mainly composed of glycine, alanine, serine and tyrosine. There have been many researches to use these two polymers simultaneously such as blends1 or crosslinked conjugates2. SF/chitosan blend can be prepared by strong hydrogen bonding between carbonyl groups in SF and amino groups in chitosan while crosslinked conjugate of SF and chitosan, which has more stable structure than blend, is formed by the addition of crosslinking agents2, commonly glutaraldehyde or isocyanate. However, a toxicity of chemical crosslinking agents can limit its application to biomedical fields. Therefore, more biocompatible crosslinking agents or other crosslinking methods without any reagents may be necessary for the application of crosslinked SF/chitosan conjugate to biomaterials. Materials and Methods Two biopolymers, silk fibroin (SF) and chitosan, were conjugated by tyrosinase (EC 1.14.18.1), a polyphenolic oxidase, to improve their physicochemical properties, such as thermal property and morphological stability in organic solvents. Before conducting the enzymatic reaction, the pH of the chitosan was adjusted to 5.0-5.5 using 1.0 M sodium hydroxide due to an inactivation of tyrosinase in low pH values. 1.0 wt% of SF and chitosan solution was mixed at various proportions. Tyrosinase solution was added in the mixed solution and then the solution was incubated at 28°C for certain times. The amount of tyrosinase was controlled to be 28.7 U/1 mL of the final solution. As a control, the solution without tyrosinase was incubated under the same condition. Results and Discussion The crosslinking reaction of SF and chitosan took place mainly via Michael addition reaction. A main reaction between amino groups in chitosan and o-quinone, oxidation product of tyrosyl residue, in SF was confirmed by UV measurement. Measurements of viscosity and light scattering showed that the crosslinked SF/chitosan conjugate was compact with smaller particle size owing to tightly bound force between SF and chitosan molecular chains. Thermal decomposition temperatures of SF/chitosan conjugate crosslinked by tyrosinase shifted to high temperature. Adhesiveness of SF/chitosan conjugate was decreased steadily as the crosslinking reaction was progressed. In this study, new crosslinking method is proposed for the preparation of silk fibroin/chitosan conjugate using tyrosinase. It is expected that the SF/chitosan conjugate crosslinked by tyrosinase can be used in biomedical applications preferably due to its unique properties and nontoxicity. References 1. X. Chen, W. Li, and T. Yu, J. Polym. Sci.:Part B: Polym. Phys., 35, 2293 (1997). 2. X. Chen, W. Li, W. Zhong, Y. Lu, and T. Yu, J. Appl. Polym. Sci., 65, 2257 (1997). |
| 저자 | 강경돈, 이기훈, 기창석, 박영환 |
| 소속 | 서울대 생물자원공학부 |
| 키워드 | Silk fibroin (SF); chitosan; conjugate; tyrosinase; crosslinking |
