(a) Osteoblast cells
(b) Osteoblast cells
(c) Mesenchymal stem cells
(d) Mesenchymal stem cells
Figure 8: Comparison of the degree of osteoblast functionality and MSC differentiation and maturation in late stage culture (3 weeks) on the TiO2 versus carbon chemistry nanotube surfaces. ALP activity for osteoblasts (a) and MSCs (c) cultured on the nanotube surfaces shows different favorable chemistries. (b) Fluorescent images showing ALP staining of osteoblast cells verifying data shown in (a). (d) Quantitative PCR analysis of the MSCs on each surface for osteocalcin and osteopontin, verifying the trend in (c).