To enhance protein production from osteoblasts by using micro-patterned surfaces

• The narrow grooves enhance cell attachment, cell alignment, expression of osteogenic proteins and biomineralization significantly.
• By reducing groove width, the osteogenic differentiation was more promoted.
• The grooved surfaces induce Smad1 phosphorylation and thus initiate BMP-Smad pathway.

In this study, microgrooved surfaces were used to culture osteoblast-like cells to promote the production of osteogenic proteins. First, modified photolithographic techniques were used on silicon wafers to create micro-grooved patterns. Groove width was continuously varied from 1 to 20 μm. Then, the cells were cultured for various periods to induce the contact guidance effect, and the cell behaviors, including the production of osteogenic proteins, were analyzed. The results indicated that the contact guidance effect was significant with suitable groove width. The guidance from topography promoted cell attachment and proliferation. Moreover, the secretion of osteogenic proteins, including alkine phosphate (ALP) and osteopontin (OPN), was greatly enhanced after cells were guided by grooved patterns. The grooved structure induced osteocalcin gene expression, revealed by the promotion of phosphorylation of Smad1. It was found that groove width less than 10 μm induced the alignment of osteoblasts, causing the increase in the production of osteogenic proteins.