Tetsushi TaguchiICBME Young Investigator Award Winner in Category: Cellular Engineering/BiomaterialsTetsushi Taguchi received his Ph.D in 1999, at Kagoshima University, Japan. He is affiliated with the Biomaterials Center, National Institute for Materials Science, Japan. His research interest lies in biomaterials science, tissue engineering and organic-inorganic hybrids. His award-winning research was titled "Encapsulation of chondrocytes in collagen-glycosaminoglycan gels prepared using poly(ethylene glycol)-based four-armed star polymer". The following is a short report on his current research. Articular cartilage has very little capacity for regeneration once damaged. Even though the damaged cartilage is replaced with a new cartilage tissue or material, the cartilage regenerated is, in general, the undesired fibrocartilage that contains type I collagen and does not have sufficient functions compared with original articular cartilage. In order to regenerate cartilage tissue using tissue engineering technology, many researchers have been investigated using porous matrices which consist of synthetic biodegradable polymers, such as poly(glycolic acid), poly(lactic acid) and their copolymers, and freeze-dried naturally-derived polymer gels. Although porous matrices have some useful properties, it is very difficult to seed cells homogeneously into the scaffolds. To overcome these problems, we developed a novel in situ encapsulation system using a crosslinker. The crosslinker employed was a four-armed star polymer bearing succinimidyl groups at the terminal of biocompatible poly(ethylene glycol) units. This crosslinker can react with various functional groups of naturally-derived polymers (collagen and glycosaminoglycan (GAG)). Using this crosslinker, we could encapsulate chondrocytes homogeneously into the composite matrices under physiological pH and salt concentration. We also confirmed that most of the cells were alive even after the encapsulation. DNA content in the matrices showed a constant value even after 3 weeks, while GAG biosynthesis was increased with an increase of culture time. After 3 weeks, GAG content in the matrices was about 10 times greater than that in the matrices just prepared (Figure 1). From an in vivo experiment, we also confirmed the promoted regeneration of cartilage defects using this system. We can easily control the encapsulation time of cells by changing various reaction conditions. As a result, we are now applying this system to the injectable cartilage-regenerative materials. For further information on the research of Dr. Taguchi, please contact him at:
Tetsushi TAGUCHI
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