Osteoblastic cellular responses to aluminosilicate nanotubes, imogolite using Saos-2 and MC3T3-E1 cells

Imogolite is a naturally occurring hydrous aluminosilicate clay mineral. It has nano-tubular structure similar to that of single-walled carbon nanotubes. Imogolite is a subject of interest in the pedological field, but to date there has been no bioapplications of this substance. In this study, we investigated the cellular response of osteoblast-like cells to imogolite scaffolds. To reveal the morphology, proliferation and osteoblastic functional mineralization, we cultured human osteoblast-like cells (Saos-2) and mouse osteoblast-like cells (MC3T3-E1) on the scaffolds. 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. Both types of osteoblast were widely spread on the imogolite scaffolds compared to their appearance in a conventional culture dish (control). The proliferation of the two types of osteoblast showed potentially useful trends. In cellular function, there was greater mineralization of both types of osteoblast on imogolite scaffolds than that of the control. Saos-2 and MC3T3-E1 cells showed good biocompatibility in addition to the enhanced osteoblastic mineralization. Therefore, imogolite is expected to be useful as a scaffold material for bone tissue engineering.