Effects of multigrooved surfaces on osteoblast‐like cells in vitro: Scanning electron microscopic observation and mRNA expression of osteopontin and osteocalcin

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Abstract
This study evaluated the behavior of osteoblast‐like cells on multigrooved surfaces consisting of a combination of microgrooves and macrogrooves. A polystyrene substrate was fabricated with multigrooves with 90‐degree, V‐shaped microgrooves with a 2‐μm pitch cut on trapezoidal macrogrooves, which had a 50‐μm ridge width, a 50‐μm wall width, a 50‐μm bottom width, and 25‐μm depth. Smooth polystyrene substrates were also prepared as controls. Rat bone marrow cells were cultured as osteoblast‐like cells on the substrates for morphological evaluation using a scanning electron microscope, and for biochemical evaluation using the quantitative reverse transcriptase‐polymerase chain reaction technique for osteopontin and osteocalcin mRNA expression. After 8 days of incubation, the osteoblast‐like cells were aligned parallel to the surface grooves on the multigrooved substrates. After 16 days of incubation, a dense mineralized extracellular matrix (ECM) was produced along the multigrooves. The ECM on the multigrooved surface appeared oriented more in the direction of the grooves than on the smooth surface, and trapezoid‐shaped macrogrooves of the ECM were cast upside down. Although there were not significant differences, the osteopontin and osteocalcin mRNA expressions of the osteoblast‐like cells on the multigrooved surfaces tended to be higher than on smooth surfaces. These results suggest that multigrooves could be used to control the orientation of mineralized ECM as well as of cells, and also to enhance the production of mineralized ECM. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 227–234, 2004