Cellular entry of nanoparticles via serum sensitive clathrin-mediated endocytosis, and plasma membrane permeabilization

Abstract

Increasing production and application of nanomaterials raises significant questions regarding the potential for cellular entry and toxicity of nanoparticles. It was observed that the presence of serum reduces the cellular association of 20 nm carboxylate-modified fluorescent polystyrene beads up to 20-fold, relative to cells incubated in serum-free media. Analysis by confocal microscopy demonstrated that the presence of serum greatly reduces the cell surface association of nanoparticles, as well as the potential for internalization. However, both in the presence and absence of serum, nanoparticle entry depends upon clathrin-mediated endocytosis. Finally, experiments performed with cells cooled to 4°C suggest that a proportion of the accumulation of nanoparticles in cells was likely due to direct permeabilization of the plasma membrane.

Keywords:

• nanoparticles
• polystyrene beads
• serum
• endocytosis
• dynamin
• clathrin
• permeabilization

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Cellular entry of nanoparticles via serum sensitive clathrin-mediated endocytosis, and plasma membrane permeabilization [Corrigendum]

Acknowledgments

The authors would like to thank Professor Mark McNiven (The Mayo Clinic, Rochester, MN) for caveolin1(Y14F) and Dr Alexandre Benmerah (Institut Cochin, Paris, France) for eps15(EH29). JM is funded through Natural Environment Research Council/Medical Research Council Project grant NE/I008314/1; PJS is funded by the Engineering and Physical Sciences Research Council through the Physical Sciences of Imaging for the Biomedical Sciences Doctoral Training Center. Finally, the authors would like to thank the following people for technical assistance and contributions to assay development: Adam Williams, Bhupesh Panchal, Georgina Harris, and Jade Ogle, as well as members of the 2011 United Kingdom Mathematics-in-Medicine Study Group for assistance with computational analyses.. The authors would also like to thank the Facility for Environmental Nanoscience Analysis and Characterisation (FENAC).