ObjectiveTo investigate the effects of micro/nano-structure and antimicrobial peptides (AMPs) on antibacterial properties of titanium (Ti) metallic surface.MethodsTi disks were treated via sandblasted large-grit acid-etched (SLA) and alkali-heat treatment (AHT) to build the micro/nano-structure, on which AMPs were spin-coated with a certain amount (10, 30, 50, 70, and 90 μg). Scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) were used to observe the surface structure and characterize the surface elements (i.e. contents of C, N, O, and Ti). Ti disks loaded with AMPs of difference amounts were co-cultured with Staphylococcus aureus (S. aureus) for 24 hours. After that, the formation and dimension of antibacterial circle were measured. Furthermore, the Ti disks treated with different approaches (untreated, SLA treatment, SLA+THA treatment, and 90 μg AMPs-loaded samples) were co-cultured with S. aureus and Escherichia coli (E.coli) for 3 hours, bacterial adhesion on the disks were evaluated by using SEM. The antibacterial performances in solution were quantitatively evaluated by immersing the Ti disks in bacterial solutions and measuring the absorbance (A) values.ResultsIt was found that the nanoporous structure could be easily constructed by SLA+AHT approach. After spin-coating AMPs, the nanopores with the diameter less than 200 nm were almost covered. According to the element analysis, with the increase of AMPs, the C content gradually increased; the N content was not detected until AMPs amount reached 70 μg on the disks. The diameter of antibacterial circle clearly depended on the AMPs amount. The Ti disks loaded with 90 μg AMPs had significantly larger antibacterial circles than the other Ti disks (P<0.05). Based on the SEM observation, the Ti disks loaded with 90 μg AMPs has the least bacterial attachment compared with the other Ti disks (P<0.05). TheA value of bacterial solution immersed with the Ti disks loaded with 90 μg AMPs was much lower than the other Ti disks (P<0.05).ConclusionThe approach of micro/nano-structure and AMPs can improve the antibacterial properties of Ti metallic surface.
Objective To reveal the relationship between the iodine nutrition and the change of spectrum of thyroiddiseases by analyzing the change of spectrum of thyroid diseases in different iodine environments before and after the implementation of universal salt iodization （USI）. Methods To compare the urinary iodine concentration between the normal people （1 000 cases） and the patients with thyroid diseases （5 998 cases） by surgical operations who were from 4 cities of Guangxi Zhuang Autonomous Region， covering the iodine deficient areas and the iodine rich areas. Results After the USI was put into practice， the proportions of nodular goiter decreased， but the proportions of toxic nodular goiter， thyroid papillary carcinoma， and Hashimoto thyroiditis were higher than those before USI （P＜0.05）. The urinaryiodine concentrations of nodular goiter， Graves disease， toxic nodular goiter， thyroid papillary carcinoma， and Hashimotothyroiditis were higher than those before the measure was taken （P＜0.05）. The urinary iodine concentration of patients with thyroid was higher than that of normal people （P＜0.05）， and the urinary iodine concentration of patients with thyroidand normal people was higher than those before the USI （P＜0.05）. Conclusions The change of spectrum of thyroid diseases in Guangxi Zhuang Autonomous Region is obvious within 10 years after USI had been taken. The excessive intake of iodine may be one of the dangerous factors leading to toxic nodular goiter， thyroid papillary carcinoma， and Hashimoto thyroiditis.
