Ayala Vanessa, Herrera Adriana P, Latorre-Esteves Magda, Torres-Lugo Madeline, Rinaldi Carlos
Department of Chemical Engineering, University of Puerto Rico, PO Box 9000, Mayagüez, PR 00681, USA.
Department of Chemical Engineering, University of Puerto Rico, PO Box 9000, Mayagü¨z, PR 00681, USA.
J Nanopart Res. 2013 Aug 1;15(8):1874. doi: 10.1007/s11051-013-1874-0.
Nanoparticle physicochemical properties such as surface charge are considered to play an important role in cellular uptake and particle-cell interactions. In order to systematically evaluate the role of surface charge on the uptake of iron oxide nanoparticles, we prepared carboxymethyl-substituted dextrans with different degrees of substitution, ranging from 38 to 5 groups per chain, and reacted them using carbodiimide chemistry with amine-silane-coated iron oxide nanoparticles with narrow size distributions in the range of 33-45 nm. Surface charge of carboxymethyl-substituted dextran-coated nano-particles ranged from -50 to 5 mV as determined by zeta potential measurements, and was dependent on the number of carboxymethyl groups incorporated in the dextran chains. Nanoparticles were incubated with CaCo-2 human colon cancer cells. Nanoparticle-cell interactions were observed by confocal laser scanning microscopy and uptake was quantified by elemental analysis using inductively coupled plasma mass spectroscopy. Mechanisms of internalization were inferred using pharmacological inhibitors for fluid-phase, clathrin-mediated, and caveola-mediated endocytosis. Results showed increased uptake for nanoparticles with greater negative charge. Internalization patterns suggest that uptake of the most negatively charged particles occurs via non-specific interactions.
纳米颗粒的物理化学性质（如表面电荷）被认为在细胞摄取和颗粒-细胞相互作用中起着重要作用。为了系统地评估表面电荷对氧化铁纳米颗粒摄取的作用，我们制备了不同取代度的羧甲基取代葡聚糖，每条链的取代度范围为38至5个基团，并使用碳二亚胺化学方法将它们与尺寸分布狭窄在33-45nm范围内的胺硅烷包覆的氧化铁纳米颗粒反应。通过zeta电位测量确定，羧甲基取代葡聚糖包覆的纳米颗粒的表面电荷范围为-50至5mV，并且取决于葡聚糖链中引入的羧甲基基团的数量。纳米颗粒与CaCo-2人结肠癌细胞一起孵育。通过共聚焦激光扫描显微镜观察纳米颗粒-细胞相互作用，并使用电感耦合等离子体质谱通过元素分析对摄取进行定量。使用针对液相、网格蛋白介导和小窝介导的内吞作用的药理抑制剂推断内化机制。结果表明，带更大负电荷的纳米颗粒摄取增加。内化模式表明，带最大负电荷的颗粒通过非特异性相互作用发生摄取。
