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Greater osteoblast proliferation on anodized nanotubular titanium upon electrical stimulation.

Ercan B, Webster TJ - Int J Nanomedicine (2008)

Bottom Line: Currently used orthopedic implants composed of titanium have a limited functional lifetime of only 10-15 years.One of the reasons for this persistent problem is the poor prolonged ability of titanium to remain bonded to juxtaposed bone.It has been proposed to modify titanium through anodization to create a novel nanotubular topography in order to improve cytocompatibility properties necessary for the prolonged attachment of orthopedic implants to surrounding bone.

View Article: PubMed Central - PubMed

Affiliation: Division of Engineering, Brown University, Providence, RI 02912, USA.

ABSTRACT
Currently used orthopedic implants composed of titanium have a limited functional lifetime of only 10-15 years. One of the reasons for this persistent problem is the poor prolonged ability of titanium to remain bonded to juxtaposed bone. It has been proposed to modify titanium through anodization to create a novel nanotubular topography in order to improve cytocompatibility properties necessary for the prolonged attachment of orthopedic implants to surrounding bone. Additionally, electrical stimulation has been used in orthopedics to heal bone non-unions and fractures in anatomically difficult to operate sites (such as the spine). In this study, these two approaches were combined as the efficacy of electrical stimulation to promote osteoblast (bone forming cell) density on anodized titanium was investigated. To do this, osteoblast proliferation experiments lasting up to 5 days were conducted as cells were stimulated with constant bipolar pulses at a frequency of 20 Hz and a pulse duration of 0.4 ms each day for 1 hour. The stimulation voltages were 1 V, 5 V, 10 V, and 15 V. Results showed for the first time that under electrical stimulation, osteoblast proliferation on anodized titanium was enhanced at lower voltages compared to what was observed on conventional (nonanodized) titanium. In addition, compared to nonstimulated conventional titanium, osteoblast proliferation was enhanced 72% after 5 days of culture on anodized nanotubular titanium at 15 V of electrical stimulation. Thus, results of this study suggest that coupling the positive influences of electrical stimulation and nanotubular features on anodized titanium may improve osteoblast responses necessary for enhanced orthopedic implant efficacy.

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SEM images showing the surface features of: (a) (low magnification), (b) (high magnification) conventional, and (c) anodized nanotubular titanium.Notes: Scale bars are: (a, b) 10 μm, and (c) 200 nm.
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f3-ijn-3-477: SEM images showing the surface features of: (a) (low magnification), (b) (high magnification) conventional, and (c) anodized nanotubular titanium.Notes: Scale bars are: (a, b) 10 μm, and (c) 200 nm.

Mentions: As determined by FESEM, the surfaces of the conventional (unanodized) and anodized nanotubular titanium confirmed that observed in previous studies (Figure 3; Yao et al 2005). Specifically, the anodization process created titania nanotubes on the titanium specimens. The diameters of the titania nanotubes ranged from 40–60 nm. Different researchers have measured different nanotube depths, varying between 200–500 nm depending on the electrolyte concentrations, times, and titanium alloy compositions used (Mor and Varghese 2003; Lee et al 2006). The depths of the nanotubes created in the present study have been estimated at 200–250 nm (Yao et al 2005).


Greater osteoblast proliferation on anodized nanotubular titanium upon electrical stimulation.

Ercan B, Webster TJ - Int J Nanomedicine (2008)

SEM images showing the surface features of: (a) (low magnification), (b) (high magnification) conventional, and (c) anodized nanotubular titanium.Notes: Scale bars are: (a, b) 10 μm, and (c) 200 nm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2636582&req=5

f3-ijn-3-477: SEM images showing the surface features of: (a) (low magnification), (b) (high magnification) conventional, and (c) anodized nanotubular titanium.Notes: Scale bars are: (a, b) 10 μm, and (c) 200 nm.
Mentions: As determined by FESEM, the surfaces of the conventional (unanodized) and anodized nanotubular titanium confirmed that observed in previous studies (Figure 3; Yao et al 2005). Specifically, the anodization process created titania nanotubes on the titanium specimens. The diameters of the titania nanotubes ranged from 40–60 nm. Different researchers have measured different nanotube depths, varying between 200–500 nm depending on the electrolyte concentrations, times, and titanium alloy compositions used (Mor and Varghese 2003; Lee et al 2006). The depths of the nanotubes created in the present study have been estimated at 200–250 nm (Yao et al 2005).

Bottom Line: Currently used orthopedic implants composed of titanium have a limited functional lifetime of only 10-15 years.One of the reasons for this persistent problem is the poor prolonged ability of titanium to remain bonded to juxtaposed bone.It has been proposed to modify titanium through anodization to create a novel nanotubular topography in order to improve cytocompatibility properties necessary for the prolonged attachment of orthopedic implants to surrounding bone.

View Article: PubMed Central - PubMed

Affiliation: Division of Engineering, Brown University, Providence, RI 02912, USA.

ABSTRACT
Currently used orthopedic implants composed of titanium have a limited functional lifetime of only 10-15 years. One of the reasons for this persistent problem is the poor prolonged ability of titanium to remain bonded to juxtaposed bone. It has been proposed to modify titanium through anodization to create a novel nanotubular topography in order to improve cytocompatibility properties necessary for the prolonged attachment of orthopedic implants to surrounding bone. Additionally, electrical stimulation has been used in orthopedics to heal bone non-unions and fractures in anatomically difficult to operate sites (such as the spine). In this study, these two approaches were combined as the efficacy of electrical stimulation to promote osteoblast (bone forming cell) density on anodized titanium was investigated. To do this, osteoblast proliferation experiments lasting up to 5 days were conducted as cells were stimulated with constant bipolar pulses at a frequency of 20 Hz and a pulse duration of 0.4 ms each day for 1 hour. The stimulation voltages were 1 V, 5 V, 10 V, and 15 V. Results showed for the first time that under electrical stimulation, osteoblast proliferation on anodized titanium was enhanced at lower voltages compared to what was observed on conventional (nonanodized) titanium. In addition, compared to nonstimulated conventional titanium, osteoblast proliferation was enhanced 72% after 5 days of culture on anodized nanotubular titanium at 15 V of electrical stimulation. Thus, results of this study suggest that coupling the positive influences of electrical stimulation and nanotubular features on anodized titanium may improve osteoblast responses necessary for enhanced orthopedic implant efficacy.

Show MeSH
Related in: MedlinePlus