Response of MG63 osteoblast-like cells to ordered nanotopographies fabricated using colloidal self-assembly and...

Ordered surface nanostructures have attracted much attention in different fields including biomedical engineering because of their potential to study the size effect on cellular response and modulation of cell fate. However, the ability to fabricate large-area ordered nanostructures is typically limited due to high costs and low speed of fabrication. Herein, highly ordered nanostructures with large surface areas (>1.5 × 1.5 cm(2)) were fabricated using a combination of facile techniques including colloidal self-assembly, colloidal lithography, and glancing angle deposition (GLAD). An ordered tantalum (Ta) pattern with 60-nm-height was generated using colloidal lithography. A monolayer of colloidal crystal, i.e., hexagonal close packed 720 nm polystyrene particles, was self-assembled and used as a mask. Ta patterns were subsequently generated by evaporation of Ta through the mask. The feature size was further increased by 100 or 200 nm using GLAD, resulting in the fabrication of four different surfaces (FLAT, Ta60, GLAD100, and GLAD200). Cell adhesion, proliferation, and mineralization of MG63 osteoblast-like cells were investigated on these ordered nanostructures over a 1 week period. Our results showed that cell adhesion, spreading, focal adhesion formation, and filopodia formation of the MG63 osteoblast-like cells were inhibited on the GLAD surfaces, especially the initial (24 h) attachment, resulting in a lower cell density on the GLAD surfaces. After 1 week culture, alkaline phosphatase activity and the amount of Ca was higher on the GLAD surfaces compared with Ta60 and FLAT controls, suggesting that the GLAD surfaces facilitate differentiation of osteoblasts. This study demonstrates that ordered Ta nanotopographies synthesized by combining colloidal lithography with GLAD can improve the mineralization of osteoblast-like cells providing a new platform for biomaterials and bone tissue engineering.