It is well known that cellular responses to materials, in terms of adhesion, migration and proliferation, are highly affected by the surface characteristics of the materials. The investigation of the effect of material surface topography on cell behaviors is of great importance for the development of implanted biomaterials in tissue engineering. Alumina is one of the most popular implant materials used in orthopedics, but few data are available concerning the potential cellular responses of MG63 to nanoporous alumina. The present study investigated the size effect of nanoporous alumina substrates on MG63 cell behaviors in terms of cell viability, expression of integrin beta 1, alkaline phosphatase (ALP) activity and changes of cell morphology, respectively. Cell viability was measured by means of MU assay and integrin beta 1 expression was detected by immunofluorescence staining and real-time PCR. Scanning electron microscopy (SEM) was used to observe cell morphology. Cell function was evaluated by detecting the ALP activity and mineralization. Results showed that cell viability and expression of integrin beta 1 were decreased with the increasing pore size, however, the increasing pore size of the alumina resulted in elongated cell morphology, enhanced ALP activity and mineralization. This study showed that the surface topography of nanoporous alumina plays an important role in regulating the behaviors of MG63 osteoblast-like cells and porous alumina can be regarded as useful substrate in tissue engineering. (C) 2013, The Society for Biotechnology, Japan. All rights reserved.