Study On The Surface Modification And Antibacterial Performance Of Polyamidoamine(PAMAM)on Titanium

Objective:The main causes of implant failure are periimplantitis and bacterial infection.Surface functionalization of titanium implant is an effective way to control the periimplantitis and reduce the bacterial infection.It will improve the long-term success rates of titanium implant.This article embarks on constructing the anti-bacterial coating by using PAMAM to modify the basified titanium implant surface,then the properties of the coating is accessed.These will provide theory basis for researching the implant with antibacterial property.Methods:1.Using divergent method for synthesis of second generation PAMAM,then PAMAM was characterized by Fourier Transform Infrared Spectroscopy(FTIR)and 1H nuclear magnetic resonance(HNMR)and transmission electron microscope(TEM).2.Assembling PAMAM on the surface of Ti implants.Scan electron microscope(SEM),x-ray energy spectra(EDX)and surface contact angle analyzer were employed to research its surface topography and structural features after assembling.3.SEM and EDX were used to detect the surface topography of titanium sheet after it was soaked in simulated body fluid(SBF)for 7 days.4.Staphylococcus aureus and colibacillus were used for antibacterial test in this study.SEM and confocal laser scanning microscopy(CLSM)quantitative analysis evaluation were applied to evaluate its early antibacterial property after bacterization 12h.After bacterization for 7d,using bacteriostasis circle to test long term bacteriostasis rate of Ti-PAMAM.Results:1.The results of FTIR,TEM and 1H NMR show that the second generation PAMAM is successfully synthesized2.SEM images showed:(1)The surface of CpTi is relatively smooth,except the trace polished by sandpaper.(2)The surface of Ti-OH is etched by NaOH,which forms cross-linked protuberance making the whole surface composing of irregular pores and the diameter of pores are about 200-300nm.(3)In Ti-PAMAM group there emerged granular structure on the surface of nano reticular after the PAMAM is fixed.The analysis result of EDS shows:(1)There is mainly element Ti on the surface of CpTi.(2)There are mainly element Ti,oxygen and sodium on the surface of Ti-OH.(3)Carbon and nitrogen adds to the surface of Ti-PAMAM.The water static contact angle of three titanium sheet are respectively 78.65?± 1.69° for CpTi;11.17°±0.89° for Ti-OH;41.55°±0.60° for Ti-PAMAM.Through pairwise comparison the difference was statistically significant(P<0.05).3.SEM and EDS results showed clustered granules on the surface of Ti-PAMAM sheet after soaked into SBF.4.Result of antibacterial property:After cultivating for 12h,there are lots of bacteria adhere to the surface of Ti-OH.But the surface of Ti-PAMAM shows different result.Based on the quantitative analysis of CLSM,the result is statistically significant.After cultivating for 7 days,the bacteriostasis circles of Ti-PAMAM towards staphylococcus aureus and colibacillus are respectively(9.15±0.28)mm and(5.95±0.28)mm.The diameter of bacteriostasis circle of Ti-OH is 0.The result of contrast is statistically significant.Conclusions:1.The surface of Ti-OH modified by PAM AM is successful,and it has good biocompatibility.2.The titanium sheet modified by PAMAM can inhibit the bacteria adhesion in early-phase.And it has good long-term antibacterial property.