title: Uptake of silver nanoparticles by monocytic THP-1 cells depends on particle size and presence of serum proteins.
abstract: Human health risks by silver nanoparticle (AgNP) exposure are likely to increase due to the increasing number of NP-containing products and demonstrated adverse effects in various cell lines. Unfortunately, results from (toxicity) studies are often based on exposure dose and are often measured only at a fixed time point. NP uptake kinetics and the time-dependent internal cellular concentration are often not considered. Macrophages are the first line of defense against invading foreign agents including NPs. How macrophages deal with the particles is essential for potential toxicity of the NPs. However, there is a considerable lack of uptake studies of particles in the nanometer range and macrophage-like cells. Therefore, uptake rates were determined over 24 h for three different AgNPs sizes (20, 50 and 75 nm) in medium with and without fetal calf serum. Non-toxic concentrations of 10 ng Ag/mL for monocytic THP-1 cells, representing realistic exposure concentration for short-term exposures, were chosen. The uptake of Ag was higher in medium without fetal calf serum and showed increasing uptake for decreasing NP sizes, both on NP mass and on number basis. Internal cellular concentrations reached roughly 32/10 %, 25/18 % and 21/15 % of the nominal concentration in the absence of fetal calf serum/with fetal calf serum for 20-, 50- and 75-nm NPs, respectively. Our research shows that uptake kinetics in macrophages differ for various NP sizes. To increase the understanding of the mechanism of NP toxicity in cells, the process of uptake (timing) should be considered.
authors: Department of Environmental Science, Radboud University Nijmegen, Nijmegen, The Netherlands.
authors: Katja
authors: 0000-0002-4446-7310
authors: K
authors: Kettler
authors: National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA Bilthoven, The Netherlands ; Department of Toxicogenomics, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands.
authors: Christina
authors: C
authors: Giannakou
authors: National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA Bilthoven, The Netherlands.
authors: Wim H
authors: WH
authors: de Jong
authors: Department of Environmental Science, Radboud University Nijmegen, Nijmegen, The Netherlands.
authors: A Jan
authors: AJ
authors: Hendriks
authors: Philips Innovation Services, HighTech Campus 7, 5656 AE Eindhoven, The Netherlands ; Institute for Environmental Studies (IVM), VU University, De Boelelaan 1087, 1081 HV Amsterdam, The Netherlands.
authors: Petra
authors: P
authors: Krystek
keywords: Biomedicine; Internal cellular concentration; Nanoparticle; Serum proteins; Size dependence; Uptake kinetics