Fig. 4
From: In vitro evaluation of osteoblast responses to carbon nanotube-coated titanium surfaces
Biocompatibility and mineralization assays on coated titanium discs. i MTT assay to assess proliferation of MC3T3-E1 cells cultured on plastic (control), uncoated Ti, MWCNT-COOH-coated Ti, and MWCNT-coated Ti after days 1, 3, and 7 (n = 5/group). *Cell proliferation on the plastic group was different from both MWCNT- and MWCNT-COOH-coated Ti discs (p = 0.03 and p = 0.02, respectively) on day 1. After day 3, cell proliferation on plastic group was significantly different (p < 0.0001) from each of the other three groups. After day 7, cell proliferation on the plastic group was significantly different (p = 0.03) with both MWCNT- and MWCNT-COOH-coated Ti discs. On day 1, plastic shows the highest amount of cell proliferation (OD570 mean ± SD) (0.71 ± 0.08) followed by uncoated (0.62 ± 0.06), MWCNT group (0.59 ± 0.05), and MWCNT-COOH group (0.58 ± 0.06). On day 3, plastic shows the highest amount of cell proliferation (1.22 ± 0.10) followed by MWCNT group (0.81 ± 0.06), MWCNT-COOH group (0.80 ± 0.06), and uncoated Ti group (0.76 ± 0.09). On day 7, plastic shows the highest amount of cell proliferation (mean ± SE) (1.06 ± 0.08) followed by uncoated Ti group (0.88 ± 0.12), MWCNT group (0.87 ± 0.09) and MWCNT-COOH group (0.86 ± 0.10). ii ALP activity of MC3T3-E1 cells cultured on plastic (control), uncoated Ti, MWCNT-COOH-coated Ti, and MWCNT-coated Ti after day 7 (n = 3/group). Mean ± SD U/μg protein for the MWCNT-COOH group was 1.0 ± 0.3, the MWCNT group (0.9 ± 0.2), the plastic group (0.8 ± 0.1), and uncoated Ti group (0.5 ± 0.01). There was no statistical significance observed among the groups using the Kruskal-Wallis test (p=0.08). iii Alizarin red staining assay of MC3T3-E1 cells cultured on plastic (control), uncoated Ti, MWCNT-COOH-coated Ti, and MWCNT-coated Ti after day 28 (n = 5/group). Matrix mineralization (mean ± SD) was highest in the MWCNT-COOH group (1.5 ± 0.2) followed by MWCNT (1.0 ± 0.5), plastic (1.00 ± 0.02), and uncoated Ti group (0.9 ± 0.1). Matrix mineralization on the uncoated group was significantly different (p = 0.03) from the MWCNT-COOH group