With contributions from USA, Taiwan, Japan, and Korea, this special issue holds great insight. This special issue offers comprehensive knowledge on chitosan and collagen as biomaterials, especially with respect to their basic biological and chemical properties, as well as clinical applications. Two review articles described the preparation and biological application of chitooligosaccharide and its derivatives and the relevance to clinical dentistry of distinct characteristics of mandibular bone collagen. Original articles reported seven experiments: 3 chitosan topics and 4 collagen topics. The former demonstrated the contributions for a proteomic view of chitosan nanoparticle to hepatic cells, the promotion of D-glucosamine to transfection efficiency, and chitin application as skin substitutes. The latter showed the contributions for hydroxyapatite-gelatin nanocomposite, genipin modification of dentin collagen, dentin phosphophoryn/collagen composite for dental biomaterial, and biological safety of fish collagen.

Acknowledgments

We owe heartily gratitude to the reviewers who helped and kindly supported us in the peer reviewing processes. We would also like to thank all the contributors who have selected the best themes and edited the meaningful concepts to this issue.

Yoshihiko Hayashi
Mitsuo Yamauchi
Se-Kwon Kim
Hideo Kusaoke