ABSTRACT
This study aimed to optimize the cleaning process of the anodized specimens for fabricating clean NiTi-O nanotubes exhibiting visible light-mediated antibacterial activity at the surface of NiTi alloy. The cleaning process of the anodized specimens tested in this study was composed of two steps. The First step included two washing solvents (distilled water and heptane) with different washing times (1, 3, and 5 min) and temperatures (25 and 80 ℃), and the second step was treated by ultrasonicator (1, 3, and 5 min). From the results of FE-SEM observation, clean and uniform nanotubes (length: 600±80 nm, diameter: 52 ±5 nm) at the surface of NiTi alloy were observed on the condition of 5 min of washing in heptane at 25 ℃ and then 3 min of ultrasonication. Thin film XRD analysis resulted that the brookite TiO 2 crystal structure being detected in the anodized specimen. Furthermore, the live-dead assay resulted that there was no significant difference among the cell viability numbers of hMSCs cultured on a cell culture dish (control), NiTi alloy, and NiTi-O nanotubes (P>0.05). Therefore, the optimized cleaning process of the anodized NiTi alloy is expected to be more feasible for the NiTi alloy-based implant surface treatment technology.
ABSTRACT
The purpose of this study was to evaluate the effect of vacuum heat treatment on the visible light remote-controlled drug release and consequent antimicrobial activity of gold nanoparticles coated on the surface of titania nanotubes. After the plasma coating of gold nanoparticles on a titania nanotube with a diameter of 100 nm, a homogeneously spherical gold shaped nanoparticle deposited on titania nanotube specimen was prepared through a vacuum heat treatment process. From the measurement of the diffuse reflective ultraviolet-visible-near-infrared spectrophotometer, the vacuum heated gold nanoparticles-titania nanotubes showed strong light absorption at the range of 400 to 650 nm. From the observation of field emission scanning electron microscopy, the size of the nanoparticles increased from 5.59±1.05 nm to 56.93±10.91 nm, and the aspect ratio also increased from 1.01±0.31 to 1.55±0.47, as the gold coating time increased from 1 minute to 9 minutes, respectively. From the results of antimicrobial drug elution test and the antibacterial test using Streptococcus mutans, before and after the visible light (wavelength 550 nm) irradiation of the antimicrobial drug (a polylactic acid containing 0.1% tetracycline) coated specimen, the drug elution value of the experimental group subjected to visible light irradiation was significantly higher than that of the control group without light irradiation (P<0.05). Also, significant antibacterial effect was evident in the experimental group subjected to visible light irradiation (P<0.05). Therefore, the study concluded that there is a possibility as an antimicrobial implant material with a visible light remote control drug elution function with the surface treatment technology of gold nanoparticles-titania nanotubes spheroidized using vacuum heat treatment.
ABSTRACT
The purpose of this study was to evaluate the effect of vacuum heat treatment on the visible light remote-controlled drug release and consequent antimicrobial activity of gold nanoparticles coated on the surface of titania nanotubes. After the plasma coating of gold nanoparticles on a titania nanotube with a diameter of 100 nm, a homogeneously spherical gold shaped nanoparticle deposited on titania nanotube specimen was prepared through a vacuum heat treatment process. From the measurement of the diffuse reflective ultraviolet-visible-near-infrared spectrophotometer, the vacuum heated gold nanoparticles-titania nanotubes showed strong light absorption at the range of 400 to 650 nm. From the observation of field emission scanning electron microscopy, the size of the nanoparticles increased from 5.59±1.05 nm to 56.93±10.91 nm, and the aspect ratio also increased from 1.01±0.31 to 1.55±0.47, as the gold coating time increased from 1 minute to 9 minutes, respectively. From the results of antimicrobial drug elution test and the antibacterial test using Streptococcus mutans, before and after the visible light (wavelength 550 nm) irradiation of the antimicrobial drug (a polylactic acid containing 0.1% tetracycline) coated specimen, the drug elution value of the experimental group subjected to visible light irradiation was significantly higher than that of the control group without light irradiation (P<0.05). Also, significant antibacterial effect was evident in the experimental group subjected to visible light irradiation (P<0.05). Therefore, the study concluded that there is a possibility as an antimicrobial implant material with a visible light remote control drug elution function with the surface treatment technology of gold nanoparticles-titania nanotubes spheroidized using vacuum heat treatment.
ABSTRACT
The purpose of this study was to fabricate platinum (Pt), one of the plasmonic nanoparticles that induces localized surface plasmon resonance (LSPR) effects caused by the pairing of plasmon with the electric field of visible-near infrared light, coated 100 nm titania (Pt-TiO2) nanotubes to evaluate the surface properties and laser mediated antibacterial effects. From the analysis of UV-VIS-NIR spectrum, the light absorptions of Pt-TiO2 nanotubes were detected at wavelengths 399–429 nm, 527–579 nm, and 806–906 nm, respectively, and one of the detected wavelengths was suitable for the laser used in this study (OCLA, Wavelength: 405). From the observation of FE-SEM, as the platinum coating time increased, the inner diameter of the Pt-TiO2 nanotubes decreased from 68.8 nm to 48.8 nm, and the shape of the platinum nanoparticles coated on the top layer of the titania nanotubes changed from spherical to rod. From the results of contact angle measurement, the contact angle of water increased from 11.94°to 19.84°as the platinum coating time increased from 1 minute to 3 minutes. The Staphylococcus aureus antibacterial test resulted that 98% or more bacterial reduction of all Pt-TiO2 nanotube groups were observed after laser irradiation (P<0.05). Live-dead assay and MTT assay indicated that laser irradiation did not affect cell death. Therefore, Pt–TiO2 nanotube exhibiting a local surface plasmon resonance effect is expected to have many potentials for semi-permanent antimicrobial implant surface treatment without antibacterial drugs.
ABSTRACT
In this study, gold nanotubes were fabricated by electrophoretic deposition using a titania nanotube layer as a template, and then the surface characteristics, biocompatibility and antibacterial effect of gold nanotubes were evaluated. Gold nanotubes of 100 nm diameter were fabricated by depositing 4 nm and 15 nm gold nanoparticles on anodized 100 nm titania nanotubes by citrate reduction and electrophoretic deposition. As a result of the UV-Vis diffuse spectrophotometer, 4 nm and 15 nm gold nanotubes showed strong absorption at 702~774 nm and 753~760 nm, respectively. Also, the maximum absorption wavelength was shifted to the longer wavelength as the coating time of the gold nanoparticles increased. FE-SEM observation and EDX analysis resulted that 0.1~0.5 wt% gold nanoparticles uniformly were stacked on the top layer of titania nanotubes. As a result of MTT cell test, the relative absorbance value of all experimental groups after 24 hours and 48 hours of incubation exceeded 70% indicating excellent biocompatibility. The effect of the near infrared laser light on the adhesion and growth of gold nanotubes showed excellent antibacterial activity regardless of the coating time of gold nanoparticles. Therefore, it is confirmed that the gold nanotube coating technology based on the titania nanotube template is supposed to be highly applicable to a titanium implant surface treatment technology with the remote control thermal treatment of a near-infrared laser.