2005 Fiscal Year Final Research Report Summary
Nano-structural Analysis of Biopolymer Gels Using Positron Annihilation Lifetime Spectroscopy
| Project/Area Number |
14380235
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Nuclear engineering
|
|---|
| Research Institution | Osaka University |
|---|
Principal Investigator |
NISHIJIMA Sigehiro Osaka Univ., Graduate School of Engineering, Prof., 大学院・工学研究科, 教授 (00156069)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
IZUMI Yoshinobu Osaka Univ., Graduate School of Engineering, Associate Prof., 大学院・工学研究科, 助教授 (60252582)
HONDA Yoshihide Osaka Univ., Graduate School of Engineering, Associate Prof., 産業科学研究所, 助教授 (40209333)
TAGAWA Seiichi Osaka Univ., Graduate School of Engineering, Prof., 産業科学研究所, 教授 (80011203)
|
|---|
| Project Period (FY) |
2002 – 2005
|
| Keywords | positron annihilation lifetime spectroscopy / diffrerncial scanning calorimetry / biopolymer gel / swelling proccess / free volume hole radius / free water / bound water / helix dtructure |
|---|
| Research Abstract |
The biomedical tissues consist chiefly of the 70-80 wt% moisture content biopolymers. Water molecules in the living body play the important role such as the substance metabolism, the ion transfer, the preservation of the tissue architecture, and the barrier from the thermal and/or chemical denaturation. To examine for the interaction between biopolymer and water, nano-structure of biopolymer gels were examined using positron annihilation lifetime spectroscopy (PALS) and differential scanning calorimeter (DSC).
Gelatin gel which is a denaturalized product of collagen was used as a model of biopolymer gel. The percentage of bound water and free water in gelatin gels were calculated from DSC curves and the result showed that the percentage of bound water increased and that of free water decreased accompanied with increase of gelatin concentration, and it was also confirmed that all of the water included in gelatin gel became bound water over the concentration of 60wt.%. Free volume hole size of gelatin gels were estimated from positron annihilation lifetime spectra using the PATFIT-88 program. Free volume hole size increased and approached to the value of pure water with increase of water content. Moreover, in the concentration region where the free water exists, the increase of free volume hole size was gradual, but rapidly increased in the concentration region where the gel including only the bound water. It indicates that, in the water swelling process of gelatin, water molecules primarily approach inside of helix structure where is hydrophilic by the existence of carboxyl group and stretch the structure. After helix structure is sufficiently stretched, water molecules approach between helix structures.
|
