Development of biomaterials with inorganic ions stimulating osteogenic cell functions

Abstract

Ceramic and polymer composite biomaterials releasing silicate and calcium ions were developed for the use in bone regeneration. Silicate and calcium ions stimulatory enhance osteogenic cell functions, such as proliferation, differentiation and mineralization. Siloxane-doped vaterite (SiV) particles were prepared using aminopropyltriethoxysilane (APTES) as a siloxane source to achieve an effective release of silicate and calcium ions in a physiological condition. Composite materials consisting of SiV and poly(lactic acid) (PLLA), which is one of the biodegradable polymers, were prepared. In this system, the amino groups and calcium ions on the SiV surface had chemical reactions with the carboxy groups in the PLLA. The composite materials showed a chronic release of trace amounts of silicate and calcium ions in a cell culture medium. Proliferation and differentiation of mouse osteoblast-like cells (MC3T3-E1 cells) were enhanced on the composite material in comparison with the material releasing no silicate ions. The composite fibremats were also developed by an electrospinning method. The fibremats had about 10 µm in fibre-diameter and showed good flexibility. The fibre surfaces were able to be coated with hydroxyapatite by soaking in a simulated body fluid (1.5SBF) for 1 day. The fibremats showed excellent cell and tissue compatibilities in the results of in vitro and vivo tests. Thus, the inorganic ions released from bioceramics should be one of the important factors for achieving high-performance biomaterials for bone regeneration.