Synopsis
Imogolite is a naturally occurring aluminosilicate clay mineral with a nanotube structure of 2 nm in diameter and 60 nm
-2 mm in length. In this study, synthetic imogolite nanotubes were used to fabricate a scaffold for cell culture and the properties of the resulting scaffold were compared with those of a conventional culture dish and a carbon nanotube (CNT) scaffold. The surface characteristics of the imogolite scaffold were drastically changed depending on the amount of imogolite on the dish. With the increase of imogolite concentration, the surface morphology of scaffolds changed from an island-like shape in random orientation to a self-organized fiber texture aligned in the same direction, and finally full coverage in a random orientation with plural layers. Osteoblast-like cells (Saos-2) cultured on imogolite showed a flat-form morphology developed in all directions in contrast to a spindle-shaped morphology developed in one direction on cell culture dishes (Cntl) and carbon nanotube scaffolds (CNT). The large growth of the cells proliferated on imogolite limited the smaller number of cells than the Cntl and CNT. However, the amount of normalized protein per cell on imogolite showed the value more than twice of that on Cntl. Imogolite contributed more to the enlargement of cell volume than proliferation. The cells cultured on the imogolite scaffold become more strongly bound to the substrate and showed high osteoblas-tic mineralization than those cultured on Cntl and CNT. The results indicate the good biocompatibility between cells and the imogolite scaffold, and suggest that imogolite could be useful for various bioapplications, such as for the fabrication of scaffolds for cell cultures, some useful proteins production (i.e. antibody, enzyme) and surface modified implants.
Key words: imogolite, nanotubes, osteoblasts, cell adhesion, mineralization
