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BP: Fachverband Biologische Physik

BP 21: Posters - Membranes and Vesicles

BP 21.1: Poster

Dienstag, 21. März 2017, 14:00–16:00, P1A

Direct proof of spontaneous translocation of lipid-covered hydrophobic nanoparticles through a phospholipid bilayer — Yachong Guo¹, Emmanuel Terazzi², Ralf Seemann³, •Jean-baptiste Fleury³, and Vladimir Baulin¹ — ¹Universitat Rovira i Virgili, Tarragona, Spain. — ²University of Geneva, Geneva, Switzerland. — ³Universität des Saarlandes, Saarbrücken, Germany.

It is generally accepted that small hydrophobic nanoparticles are blocked by lipid bilayers and accumulate in the bilayer core, whereas big nanoparticles can only penetrate cells through slow energy-dependent processes, such as endocytosis, lasting minutes. In contrast to expectations, we demonstrate that lipid-covered hydrophobic nanoparticles may translocate through lipid membranes by direct penetration within milliseconds. We identified the threshold size for translocation: nanoparticles with diameters smaller than 5 nm stay trapped in the bilayer, whereas those with diameters larger than 5 nm insert into the bilayer, opening pores in the bilayer. The direct proof of this size-dependent translocation was provided by an in situ observation of a single event of a nanoparticle quitting the bilayer. This was achieved with a specially designed microfluidic device combining optical fluorescence microscopy with simultaneous electrophysiological measurements. A quantitative analysis of the kinetic pathway of a single nanoparticle translocation event demonstrated that the translocation is irreversible and that the nanoparticle can translocate only once.

Science Advances 2, e1600261 (2016)