Sussman Eric M, Casey Brendan J, Dutta Debargh, Dair Benita J
Division of Biology, Chemistry and Materials Science, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, US Food and Drug Administration, 10903 New Hampshire Ave., Silver Spring, MD, 20993, USA.
J Appl Toxicol. 2015 Jun;35(6):631-9. doi: 10.1002/jat.3104. Epub 2015 Feb 2.
This study was performed to understand how the choice of cytotoxicity assay format affects the observed biocompatibility of nanosilver (nAg). nAg coatings are physical coatings containing silver (Ag) that have feature sizes of 100 nm or less, often in the form of nanoparticles or grains. They are used on medical devices to prevent infection, but in spite of this intended benefit, observations of potential cytotoxicity from nAg have been reported in numerous published studies. For medical device regulation, cytotoxicity testing is part of a biocompatibility evaluation, in which specific test methods are chosen based on the technological characteristics and intended use of a device. For this study, nAg-coated tissue culture polystyrene surfaces were prepared using magnetron sputter coating, resulting in nAg films of 0.2 to 311 µg cm(-2) Ag. These coatings exhibited nanometer-scale morphologies and demonstrated a > 4log10 reduction in Escherichia coli viability. It was observed that extracts of nAg caused no cytotoxicity to L929 mouse fibroblasts, but cells cultured directly on nAg coatings (direct-contact assay format) showed a dose-dependent reduction in viability by up to 100% (P < 0.001). Results using inductively coupled plasma mass spectrometry to measure Ag release suggested that extracts of nAg are not toxic because the dissolved Ag in those samples becomes less cytotoxic over time, probably owing to the reaction with cell culture media and serum (six-fold cytotoxicity reductions observed over a 24-h period). These findings highlight the potential value of direct-contact cytotoxicity testing for nAg in predicting biological interactions with cells or tissue in vivo.
进行这项研究是为了了解细胞毒性测定形式的选择如何影响纳米银（nAg）的生物相容性观察结果。nAg涂层是含有银（Ag）的物理涂层，其特征尺寸为100纳米或更小，通常呈纳米颗粒或晶粒的形式。它们被用于医疗设备以预防感染，但尽管有这种预期的益处，在众多已发表的研究中都报道了nAg潜在的细胞毒性观察结果。对于医疗器械监管而言，细胞毒性测试是生物相容性评估的一部分，在该评估中，会根据设备的技术特性和预期用途选择特定的测试方法。在本研究中，使用磁控溅射涂层制备了nAg涂层的组织培养聚苯乙烯表面，得到了银含量为0.2至311微克/平方厘米的nAg薄膜。这些涂层呈现出纳米级形态，并证明对大肠杆菌的活力有大于4个对数级的降低。观察到nAg提取物对L929小鼠成纤维细胞无细胞毒性，但直接在nAg涂层上培养的细胞（直接接触测定形式）显示活力呈剂量依赖性降低，最高可达100%（P<0.001）。使用电感耦合等离子体质谱法测量银释放的结果表明，nAg提取物无毒，因为这些样品中溶解的银随着时间的推移细胞毒性降低，可能是由于与细胞培养基和血清发生了反应（在24小时内观察到细胞毒性降低了六倍）。这些发现突出了nAg直接接触细胞毒性测试在预测体内与细胞或组织的生物相互作用方面的潜在价值。
