Objective Iodine loading would be carried out on orthopedic titanium Kirschner-wire by electrophoretic deposition.And by this,a kind of orthopedic iodine-coated implant with antibacterial properties was supposed to be developed,that would provide a theoretical basis for the development of clinical orthopedic implants with antibacterial properties.Methods Iodine loading on the surface of titanium Kirschner-wire was carried out by electrophoretic deposition.PVP-I solution as 1 000 ppm,2 000 ppm and 4 000 ppm was prepared respectively (1 ppm=1 mg/kg=1 mg/L).Three kinds of iodine-coated orthopedic titanium Kirschner-wires with different iodine content were prepared by electrophoretic deposition at 200 V voltage for 30 min and then stoved after being washed with distilled water.The surface signs and composition structure of iodine coated titanium Kirschnerwire were studied through scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS).Antibacterial experiments of Iodine coating titanium Kirschner needle were performed in vitro.Antimicrobial test:10 pieces of uncoated titanium Kirschner-wires;10 pieces of iodine-coated titanium Kirschner-wires with 1 000 ppm;10 pieces of iodine-coated titanium Kirschner-wires with 2 000 ppm;10 pieces of iodine-coated titanium wires with 4 000 ppm.Because iodine is easy to sublimate and does not withstand high temperature,all the titanium Kirschner needles are fumigated and disinfected by ethylene oxide (supported by the supply room of our hospital).Titanium wires were immersed respectively in 106 CFUJ/ml (ATCC25923) bacterial suspension of standard Staphylococcus aureus so that bacteria would be fully inoculated on the surface of the titanium wire.The sterilized titanium Kirschner needle was placed in a sterile culture cup and 30 ml suspension was added into the culture cup.The sterilized titanium Kirschner needle was completely immersed in the bacterial solutionand was kept at 37°C for 6 h before taking out.Take out the titanium Kirschner needle slowly,rinse the titanium Kirschner needle with 5 ml sterile PBS buffer,after rinsing the surface of titanium Kirschner needle,transfer the titanium Kirschner needle to the new sterile culture cup and add 5 ml sterile saline until the titanium Kirschner needle is completely immersed.Then put the titanium Kirschner needle into the ultrasonic oscillator to wash the surface of the bacteria fully.After 10 000 times dilution,100 μl was smeared on agar medium for culture (37°C) and the number of colonies was observed and counted 24 h later.Results The surface of three kinds of iodine coating titanium Kirschner-wires was covered with uniform iodized compound coating and had a brown look.The film structure was stable and there was no falling off after ultrasonic cleaning.SEM exhibited that the surface of Titanium Kirschner-wire is covered with a compact coating;the appearance structure is relatively flat and a slight collapse can be seen scattered in the surface of the wire.The results of EDS showed that the iodine content in the surface coating of 3 groups was 4.38 wt％,9.05 wt％ and 14.48 wt％.The bacteria growing on the surface of titanium needle were shaken down by ultrasonic vibration.The CFU counting was carried out after the bacterial solution being diluted,coated and cultured for 24 h.It can be seen that the antibacterial property increases continuously with the increase of iodine coating content.The antibacterial properties of iodine-coated implant which content 14.48 wt％ iodine was more than 1 orders of magnitude than the control group.The results showed that the plants coated with iodine had obvious antibacterial effect.Conclusion The iodine coated titanium wire was prepared by electrophoretic deposition,after being characterized by SEM,EDS and quantitative measurement,the successful loading of iodine was proved,the antibacterial experiment proved that the iodinecoated orthopedic titanium Kirschner-wire has a stronger antibacterial properties than the ordinary titanium Kirschner-wire under laboratory conditions.

Objective:To explore the feasibility of preparing an iodine-coated titanium plate with potassium iodide and verify its antibacterial performance.Methods:Iodine was coated onto the surface of a titanium plate in electrolyte of potassium iodide using the electrophoretic deposition method. The signs and composition of the surface of the iodine-coated titanium plate were observed by scanning electron microscopy and energy dispersive spectroscopy. The experiment was conducted in a control group and 3 antibacterial test groups. The control group consisted of 10 titanium plates which had been pretreated but not loaded with iodine; the 3 experimental groups also had in each 10 titanium plates which had been pretreated and loaded with iodine in the electrolytes of concentrations of 1,000 mg/L, 2,000 mg/L and 4,000 mg/L, respectively. The antimicrobial tests in vitro were conducted with standard strains of staphylococcus aureus [1×10 6 Colony-Forming Units (CFU)/mL ATCC25923] to determine the antibacterial property of the plates. Results:The iodine-coated titanium plates appeared grey and their surface was evenly covered with a flat coating with no collapse. The scanning electron microscopy observed on the surface of the iodine-coated titanium plates an iodine coating with scattered irregular collapses in different sizes. The iodine content was 0 mass%, 5.10 mass%, 10.32 mass% and 15.05 mass%, respectively, in the control, 1,000 mg/L, 2,000 mg/L and 4 000 mg/L groups under the energy dispersive spectroscopy. Their counts of in vitro antibacterial colony were 56.00±5.09, 21.40±2.76, 9.10±2.51, and 2.00±1.88, respectively, showing significant differences between groups ( P< 0.05). Conclusions:A titanium plate with a steady and even iodine coating can be prepared by virtue of the electrophoretic deposition method in electrolyte of potassium iodide. The antibacterial property of an iodine-coated titanium plate is superior to that of a titanium plate without iodine coating.