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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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Osteoblast densities from 1 to 5 days on anodized nanotubular titanium.Notes: Values are mean ± SEM; n = 3; *p < 0.05 compared to Non_1st day; **p < 0.05 compared to Non_3rd day; +p < 0.05 compared to 1 V_1st day; ++p < 0.05 compared to 1 V_3rd day; ¥p < 0.05 compared to 5 V_1st day; ¥¥p < 0.05 compared to 5 V_3rd day; ‡p < 0.05 compared to 10 V_1st day; ‡‡p < 0.05 compared to 10 V_3rd day; #p < 0.05 compared to 15 V_1st day; and ##p < 0.05 compared to 15 V_3rd day.Abbreviation: Non, nonelectrical stimulated.
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f8-ijn-3-477: Osteoblast densities from 1 to 5 days on anodized nanotubular titanium.Notes: Values are mean ± SEM; n = 3; *p < 0.05 compared to Non_1st day; **p < 0.05 compared to Non_3rd day; +p < 0.05 compared to 1 V_1st day; ++p < 0.05 compared to 1 V_3rd day; ¥p < 0.05 compared to 5 V_1st day; ¥¥p < 0.05 compared to 5 V_3rd day; ‡p < 0.05 compared to 10 V_1st day; ‡‡p < 0.05 compared to 10 V_3rd day; #p < 0.05 compared to 15 V_1st day; and ##p < 0.05 compared to 15 V_3rd day.Abbreviation: Non, nonelectrical stimulated.

Mentions: As expected, the results of the present study also demonstrated that osteoblasts grew on both conventional and anodized nanotubular titanium with culture time (from 1 to 3 to 5 days) (Figures 7 and 8). Table 1 lists the percent increases in osteoblast numbers up to 5 days of culture on the substrates of interest to the present study. When the percent increases in osteoblast densities from the 1st to 3rd days of culture are compared, they were found to be higher for conventional titanium compared to anodized nanotubular titanium for all test conditions (excluding the 10 V stimulation, the same voltage consistently highlighted on anodized nanotubular titanium as the one in which osteoblasts performed statistically similar to osteoblasts on conventional titanium at 15 V). Upon comparison of the percent increases in osteoblast densities from the 3rd to 5th days of culture, they were higher for osteoblasts on anodized compared to their conventional counterparts for all voltage conditions. In fact, when percent increases in cell densities from the 1st to 3rd days and from the 3rd to 5th days are compared, osteoblast proliferation was found to decrease with time more on conventional titanium samples than anodized nano-tubular titanium. While the reasons for these trends are not clear at this time, it is important to note that, as mentioned, more osteoblasts were present on anodized nanotubular than conventional titanium after 1 day and it is possible that the combined effects of altered titanium surface properties obtained through anodization and electrical stimulation are responsible for these complex trends.


Greater osteoblast proliferation on anodized nanotubular titanium upon electrical stimulation.

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

Osteoblast densities from 1 to 5 days on anodized nanotubular titanium.Notes: Values are mean ± SEM; n = 3; *p < 0.05 compared to Non_1st day; **p < 0.05 compared to Non_3rd day; +p < 0.05 compared to 1 V_1st day; ++p < 0.05 compared to 1 V_3rd day; ¥p < 0.05 compared to 5 V_1st day; ¥¥p < 0.05 compared to 5 V_3rd day; ‡p < 0.05 compared to 10 V_1st day; ‡‡p < 0.05 compared to 10 V_3rd day; #p < 0.05 compared to 15 V_1st day; and ##p < 0.05 compared to 15 V_3rd day.Abbreviation: Non, nonelectrical stimulated.
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Related In: Results  -  Collection

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f8-ijn-3-477: Osteoblast densities from 1 to 5 days on anodized nanotubular titanium.Notes: Values are mean ± SEM; n = 3; *p < 0.05 compared to Non_1st day; **p < 0.05 compared to Non_3rd day; +p < 0.05 compared to 1 V_1st day; ++p < 0.05 compared to 1 V_3rd day; ¥p < 0.05 compared to 5 V_1st day; ¥¥p < 0.05 compared to 5 V_3rd day; ‡p < 0.05 compared to 10 V_1st day; ‡‡p < 0.05 compared to 10 V_3rd day; #p < 0.05 compared to 15 V_1st day; and ##p < 0.05 compared to 15 V_3rd day.Abbreviation: Non, nonelectrical stimulated.
Mentions: As expected, the results of the present study also demonstrated that osteoblasts grew on both conventional and anodized nanotubular titanium with culture time (from 1 to 3 to 5 days) (Figures 7 and 8). Table 1 lists the percent increases in osteoblast numbers up to 5 days of culture on the substrates of interest to the present study. When the percent increases in osteoblast densities from the 1st to 3rd days of culture are compared, they were found to be higher for conventional titanium compared to anodized nanotubular titanium for all test conditions (excluding the 10 V stimulation, the same voltage consistently highlighted on anodized nanotubular titanium as the one in which osteoblasts performed statistically similar to osteoblasts on conventional titanium at 15 V). Upon comparison of the percent increases in osteoblast densities from the 3rd to 5th days of culture, they were higher for osteoblasts on anodized compared to their conventional counterparts for all voltage conditions. In fact, when percent increases in cell densities from the 1st to 3rd days and from the 3rd to 5th days are compared, osteoblast proliferation was found to decrease with time more on conventional titanium samples than anodized nano-tubular titanium. While the reasons for these trends are not clear at this time, it is important to note that, as mentioned, more osteoblasts were present on anodized nanotubular than conventional titanium after 1 day and it is possible that the combined effects of altered titanium surface properties obtained through anodization and electrical stimulation are responsible for these complex trends.

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