纳米载银树脂中抗菌剂的分散及银离子析出的观察

摘要

目的 研究纳米载银树脂中抗菌剂的分散及银离子的析出情况,为进一步研究其加工工艺、抗菌长效性及使用安全性提供依据.方法 用球磨法将以磷酸复盐为载体的纳米载银抗菌剂STR-1按一定比例添加到义齿基托聚合物粉体中,制作抗菌剂浓度分别为0、5和10 g/L的3组纳米载银树脂片各6片,其中3片规格为10 mm×10 mm×1 mm,用于扫描电镜观察树脂片表面抗菌剂的分散情况;另外3片规格为70 mm×70 mm×2.5 mm,分别浸泡在人工唾液中,每24 h取样1次,用电感耦合等离子质谱法测定银离子的平均析出量,观察54 d.结果 扫描电镜下可见纳米载银抗菌剂在树脂片中分散较均匀,有少量较小的团聚体,无大的团聚体形成;抗菌剂含量为5 g/L和10 g/L的纳米载银树脂片在人工唾液中浸泡54 d后累积析出银离子分别为0.953 μg和2.520 μg,分别占各自银离子总含量的0.026%和0.034%.银离子析出速度非常缓慢,银离子累积析出曲线呈"S"型,早期析出缓慢,中期析出相对加速,后期又趋于缓慢、稳定.结论 纳米载银抗菌剂STR-1可较均匀地分散于树脂中,54 d内纳米载银树脂中银离子析出微量且速度缓慢.%Objective To investigate the distribution of antimicrobial agent STR-1 of nanometer level which was incorporated with ball-grinding method in the polymethylmethacrylate(PMMA)denture base,and to study the release mode of silver ions from the base. Methods The distribution of the antimierobial agent in the PMMA denture base containing STR-1 at concentrations of 0 g/L,5 g/L,and 10 g/L Was examined with scanning electronic microscopy. Then,PMMA resin bases containing STR-1 at the three concentrations were respectively immersed in artificial saliva at 37 ℃ f0r 54 days. The release of silver ions from the resin bases was surveyed with inductively coupled plasma-mass spectroscopy(ICP-MS)every 24 hours.Results The antimicrobial agent incorporated by ball-grinding method was even-distributed with individual particles of nanometer level in the PMMA resin base.The release of silver ions from the PMMA resin with antimicrobial agent was extremely slow during the test,a very small fraction of the silver ions released.At the beginning of the test,the release speed was extremely slow,the speed increased rapidly in tlle middle of the test,and at the end of the test,the speed returned to slow and steady. The cumulative release curve of silver ions was of"S" type.Conclusions STR-1 can be even-distributed in the denture base,and the silver ions release from the base with extremely slow speed.It also indicates that biological safety and long-term antimicrobial efficacy of denture base containing silver-supported antimicrobial agents of nanometer level are possibly obtained based on their slow release of silver ions.