Effect Of Antibacterial Activity And Bioactive On Titania Nanotubes

Objective:Osseointegration is the key of a success implant denture. Different kinds of surface modification have been made to improve the implants antibacterial ability and biological activity so as to raise early osseointegration of dental implants and increase initially weight-bearing bones of dental implants. In the study,we build micro/nanorough surfacethrough hydrofluoric acid etching and anodizing at first, then the SEM are used to characterize the structure and surface properties of the TiO2 nanotubes, determine the OCN mRNA gene expression levels between different groups by Reverse transcription-polymerase chain reaction(RT-PCR) and quantitative real-time PCR analysis. We can obtain valuable parameters in the use of TiO2 nanotubes in the future.Materials and Methods:1. Pure titanium plates surface are polished by sandpaper of silicon carbide. These disks are ultrasonically degreased in acetone and ethanol for 10 minutes with deionized water rinsing between applications of each solvent. The titanium samples are treated by 0.5wt% hydrofluoric acid etching for 30 minutes, then anodized for 40 minutes in an electrolyte containing 0.2 wt% hydrofluoric acid using a DC power supply with a platinum electrode as the cathode. The samples are then divided into 2groups. Control group is a nontreated machined Ti surface. The experiental group is an anodized micro/nanorough TiO2 surface. Scanning electron microscope are used to observe the morphology of samples. Talor hobson surface roughometer is used to measure the surface roughness.2. Three sterilization processes used in the studies, namely autoclaving, ethanol immersion and ultraviolent irradiation, were adopted in this study. Field emission scanning electron microscopy was utilized to observe the surface topography of the prepared specimens. Contact angle measurements were carried out by the sessile drop method on a contact angle measuring system. The film contact method is used to evaluate the antibacterial activity of samples with Staphylococcus aureus(Sa) after different infection treatment. The bacterial morphology is observed by field emissionscanning electron microscope(FE-SEM).3. After cells cultured on the sanples for 7 days, total RNA are isolated. To determine the OCN mRNA gene expression levels between different groups by Reverse transcription-polymerase chain reaction(RT-PCR) and Quantitative real-time PCR analysis.Results:1. The titanium samples are treated by 0.5wt% hydrofluoric acid etching for 30 minutes, then anodized for 40 minutes in an electrolyte containing 0.2 wt%hydrofluoric acid.The pure Ti surface can be formed a micro/nanorough surface. The anodized TiO2 surface showed relatively well-developed columnar structures and a porous oxide layer compared with the pure Ti surface. The experimental group has higher surface roughness.2. The water contact angle of the anodized TiO2 surface was significantly lower than the pure Ti surface after exposure to ultraviolet light. The bacterial adhesion ability of experimental group is stronger compared with control group. The contracting angle of samples exposed to UV irradiation is smaller than that of alcohol immersion and autoclaving treatment group. Viable count and FE-SEM showed that the samples after alcohol immersion have more bacteria and more complete morphology on their surface. Autoclaving takes the second place. UV irradiation leads to the minimum.3. The experimental group sample can upregulate the expression of the OCN mRNA.Conclusions:1. Titania nanotubes are successfully fabricated with a homogeneous and uniform array of nanopores after hydrofluoric acid etching and anodization.2. UV irradiation show the best antibacterial activity.3. The gene expression of osteogenic markers OCN is upregulated by the titanium anodic oxidation modification.