Nano Biomedicine

Subcutaneous Tissue Reactions Against Nano-apatite Collagen Composites

Wataru HATAKEYAMA1, Masayuki TAIRA2, Hidemichi KIHARA1, Minoru SASAKI3, Shigenobu KIMURA3, and Hisatomo KONDO1

1Department of Prosthodontics and Oral Implantology,
Iwate Medical University School of Dentistry, Morioka, Japan
2Department of Biomedical Engineering, Iwate Medical University,
3Division of Molecular Microbiology, Department of Microbiology,
Iwate Medical University, Yahaba-chou, Iwate, Japan

Nano Biomedicine 2012;4(2):118-124, (Dec 30)

The in vivo reaction against nano-apatite is still not well understood. We self-prepared four samples using medical-grade collagen and commercial (40 nm) nano-apatite particles (n-HAp), namely (i) collagen sponge (sample C), (ii) n-HAp collagen composite sponge (sample AC), (iii) collagen sponge with basic fibroblast growth factor (b-FGF) (sample CF) and (iv) n-HAp collagen composite sponge with b-FGF (sample ACF); and implanted them in subcutaneous tissues of the back of mice for 1 and 2 weeks. Visual inspections and histological observations revealed that sample ACF caused most intensified angiogenesis with time, followed by sample CF and sample AC, while sample C caused little angiogenesis. More the angiogenetic, more the foreign body reactions. It was confirmed that n-HAp bound in collagen sponge was safe and bio-absorbable; and n-HAp had mi-nor capability of angiogenesis, and if coupled with b-FGF, strong capability of angiogenesis at the implanted site in soft tissues. This biological property could be useful for regeneration of hard tissues as well as soft tissues in the future clinical applications.

Key words: nano-apatite, collagen composite, subcutaneous tissues, angiogenesis, organization

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