Grant-in-Aid for Creative Scientific Research
|Allocation Type||Single-year Grants |
|Research Institution||Hokkaido University |
OSADA Yoshihito Hokkaido University, Faculty of Science, Professor (60007804)
GONG Jian Ping Hokkaido University, Faculty of Science, Professor (20250417)
YASUDA Kazunori Hokkaido University, Graduate School of Medicine, Professor (20166507)
YAGI Toshirou Hokkaido University, Professor Emeritus (30002132)
YAMAMOTO Masafumi Hokkaido University, Graduate School of Information Science and Technology, Professor (10322835)
KAWABATA Kazushige Hokkaido University, Faculty of Science, Professor (20261274)
|Project Period (FY)
2002 – 2006
Completed (Fiscal Year 2006)
|Budget Amount *help
¥686,400,000 (Direct Cost: ¥561,120,000、Indirect Cost: ¥125,280,000)
Fiscal Year 2006: ¥135,720,000 (Direct Cost: ¥104,400,000、Indirect Cost: ¥31,320,000)
Fiscal Year 2005: ¥135,720,000 (Direct Cost: ¥104,400,000、Indirect Cost: ¥31,320,000)
Fiscal Year 2004: ¥135,720,000 (Direct Cost: ¥104,400,000、Indirect Cost: ¥31,320,000)
Fiscal Year 2003: ¥135,720,000 (Direct Cost: ¥104,400,000、Indirect Cost: ¥31,320,000)
Fiscal Year 2002: ¥143,520,000 (Direct Cost: ¥143,520,000)
|Keywords||Actuator / Tough gel / Artificial muscle / Double network / Artificial cartilage / Low friction / Bio-compatibility / Soft machine / DNゲル / 高分子ゲル / ソフト&ウェットマター / ナノバイオマシン / ソフト&ウェットアクチュエータ / 超高強度 / 超低摩擦 / 超高強度超低摩擦ゲル / 生体適合性 / コンプレックス形成|
(I) Synthesis of hydrogel as soft and wet artificial muscles
By introducing the double network structure into hydrogel, we succeeded in obtaining the hydrogel with extra-ordinary high mechanical toughness (Fracture strength of about several Mpa).
In addition, by changing the inhomogeous structure of the first network from several 10nm to micrometer, we succeeded in controlling the mechanical behavior of the DN gel from brittle-like to ductile-like. The ductile-like DN gel exhibits an elongation as high as 20 times before failure. To apply this gel as artificial cartilage, we further introduced the graft structure to the DN gel surface and succeeded in obtaining the gel with a fracture stress of several 10MPa, fracture energy of 1000 J/cm^2, and sliding friction coefficient of 10^<-5>〜10^<-4>.
(II) Application of hydrogel as substitutes of bio-organs
To apply the gel with excellent mechanical properties as artificial cartilage, wear property, bio-durability and biocompatibility were investigated. Several kinds of DN gels sustained cyclic pin-on-flat test for one million times with a total sliding distance of 50 km, and showed a wearing rate of 10^<-8>-10^<-7>mm^3/Nm. This wear resistance is higher than that of the high density polyethylene (wearing rate of 10^<-7>mm^3/Nm).
Implantation test of DN gel in the rabbits showed that among several kinds of DN gels, the PAMPS/PDMAAm DN gel was the most suitable for bio-durability. Moreover, it was found that the gel showed a good biocompatibility when artificial cartilage made of PAMPS/PDMAAm was implanted in the articular joints of rabbits.
Furthermore, we discovered that normal cartilage was regenerated in situ when the PAMPS/PDMAA gel was imbedded into the articular joint several mm from the surface as artificial cartilage. This great discovery will lead to a completely new method to repair the damaged cartilage in situ.