Abstract
Background: The effects of surface roughness and carboxyl functionalization of multi-walled carbon nanotubes (MWCNTs) mixed with collagen coated onto titanium (Ti) substrates on MC3T3-E1 osteoblasts were evaluated. Methods: The proliferation, differentiation, and matrix mineralization were investigated using (1) smooth-surfaced Ti discs, (2) Ti discs coated with collagen and MWCNT (Ti-MWCNT), and (3) Ti discs coated with collagen and MWCNT-COOH (Ti-MWCNT-COOH) for applications in orthodontic mini screw implants (MSIs). The coatings were uniform when analyzed using scanning electron microscopy (SEM), and surface roughness was evaluated by surface profilometry that demonstrated similar surface roughness (Ra, mean ± SD) in the MWCNT (0.83 ± 0.02 μm) and MWCNT-COOH (0.84 ± 0.01 μm) groups. MTT (3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide) assay was performed after days 1, 3, and 7 to assess proliferation. Alkaline phosphatase (ALP)-specific activity was assessed after day 7 to quantify differentiation. Alizarin red staining was measured after day 28 to quantify matrix mineralization. All data were analyzed with JMP Pro11 software (SAS, USA) with a statistical significance of p < 0.05. Results: Surface profilometry demonstrated similar surface roughness (Ra, mean ± SD) in the MWCNT (0.83 ± 0.02 μm) and MWCNT-COOH (0.84 ± 0.01 μm) groups. On day 7, ALP assay showed that MWCNT-COOH (mean ± SD 0.98 ± 0.26 U/μg of protein) enhanced cell differentiation when compared to the uncoated group (p = 0.05). Alizarin red staining after 28 days of cell culture revealed that MWCNT-COOH (mean ± SD 1.5 ± 0.2 OD405) increased (p = 0.03) matrix mineralization when compared to the uncoated group (0.9 ± 0.09 OD405). Conclusions: This study showed that coatings containing MWCNT-COOH (increased hydrophilic surface chemistry) influence osteoblast proliferation, differentiation, and matrix mineralization and should be further studied for applications in orthodontic MSIs.
Original language | English |
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Article number | 23 |
Journal | Progress in Orthodontics |
Volume | 17 |
Issue number | 1 |
DOIs | |
State | Published - Dec 1 2016 |
Bibliographical note
Publisher Copyright:© 2016, The Author(s).
Funding
This study was supported by Research Aid Award (RAA) (2013–2015) from the American Academy of Orthodontists Foundation (AAOF). Titanium discs were donated by Straumann, Switzerland. The authors would like to acknowledge Mr. Brock Marrs (NuForm Materials, USA) for providing the carbon nanotubes.
Funders | Funder number |
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American Academy of Orthodontists Foundation | |
RAA | |
American Association of Orthodontists Foundation |
Keywords
- Multi-walled carbon nanotubes
- Orthodontic mini screw implants
- Osteoblast response
- Temporary anchorage devices
- Titanium
ASJC Scopus subject areas
- Orthodontics