Center for Surface Chemistry & Catalysis, Katholieke Universiteit Leuven, Kasteelpark Arenberg 23, 3001 Heverlee, Belgium.
Langmuir. 2010 Jan 5;26(1):328-35. doi: 10.1021/la902050k.
For the investigation of the interaction of nanoparticles with biomolecules, cells, organs, and animal models there is a need for well-characterized nanoparticle suspensions. In this paper we report the preparation of monodisperse dense amorphous silica nanoparticles (SNP) suspended in physiological media that are sterile and sufficiently stable against aggregation. SNP sols with various particle sizes (2-335 nm) were prepared via base-catalyzed hydrolysis and polymerization of tetraethyl orthosilicate under sterile conditions using either ammonia (Stober process (1) ) or lysine catalyst (Lys-Sil process (2) ). The series was complemented with commercial silica sols (Ludox). Silica nanoparticle suspensions were purified by dialysis and dispersed without using any dispersing agent into cell culture media (Dulbecco's Modified Eagle's medium) containing antibiotics. Particle sizes were determined by dynamic light scattering. SNP morphology, surface area, and porosity were characterized using electron microscopy and nitrogen adsorption. The SNP sols in cell culture medium were stable for several days. The catalytic activity of the SNP in the conversion of hydrogen peroxide into hydroxyl radicals was investigated using electron paramagnetic resonance. The catalytic activity per square meter of exposed silica surface area was found to be independent of particle size and preparation method. Using this unique series of nanoparticle suspensions, the relationship between cytotoxicity and particle size was investigated using human endothelial and mouse monocyte-macrophage cells. The cytotoxicity of the SNP was strongly dependent on particle size and cell type. This unique methodology and the collection of well-characterized SNP will be useful for further in vitro studies exploring the physicochemical determinants of nanoparticle toxicity.
为了研究纳米粒子与生物分子、细胞、器官和动物模型的相互作用，需要制备具有良好特性的纳米粒子悬浮液。本文报道了在生理介质中制备单分散无定形二氧化硅纳米粒子（SNP）悬浮液的方法，该悬浮液无菌且足够稳定，不易聚集。通过在无菌条件下使用氨（Stober 法（1））或赖氨酸催化剂（Lys-Sil 法（2）），使正硅酸乙酯在碱性条件下水解和聚合，制备出具有不同粒径（2-335nm）的 SNP 溶胶。该系列还补充了商业二氧化硅溶胶（Ludox）。通过透析对二氧化硅纳米粒子悬浮液进行纯化，并在不使用任何分散剂的情况下将其分散到含有抗生素的细胞培养基（Dulbecco's Modified Eagle's medium）中。通过动态光散射法测定粒径。利用电子显微镜和氮气吸附法对 SNP 的形态、比表面积和孔隙率进行了表征。SNP 溶胶在细胞培养基中可稳定数天。利用电子顺磁共振研究了 SNP 在将过氧化氢转化为羟基自由基过程中的催化活性。发现暴露于二氧化硅表面的 SNP 的催化活性与粒径和制备方法无关。使用该独特的纳米粒子悬浮液系列，研究了人内皮细胞和小鼠单核细胞-巨噬细胞中粒径与细胞毒性的关系。SNP 的细胞毒性强烈依赖于粒径和细胞类型。这种独特的方法和一系列特性良好的 SNP 将有助于进一步研究探索纳米粒子毒性的物理化学决定因素的体外研究。
