title: Absolute quantitation of sub-micrometer particles in cells by flow cytometry.
abstract: Absolute quantitative measurements of nanoparticle (NP) uptake are a prerequisite to determine doses of NPs in pharmacological and toxicological studies. However, absolute quantitation is rarely reported, hindering the comparison between different studies. Here, a new flow cytometric approach is presented to analyze fluorescent NPs with a "standard" non-scanning flow cytometer and to quantify them inside cells. The mean fluorescence intensity of a single particle and the particle concentration (NPs per μL medium) are obtained. A routine for rapid quantitative counting of the endocytosed NPs in HeLa cells by flow cytometry (FC) is developed and validated by confocal laser scanning microscopy. As a proof-of-concept, the quantitative measurements show that the cellular uptake efficiency of negatively charged poly(methyl methacrylate) NPs is very low, that is, in the range of 10(-3) % of the added particle amount.
authors: Max Planck Institute for Polymer Research, Ackermannweg 10, 55129, Mainz, Germany.
authors: Anita
authors: A
authors: Höcherl
authors: Katharina
authors: K
authors: Landfester
authors: Volker
authors: V
authors: Mailänder
mesh_terms: D001896:Boron Compounds / Q000737:chemistry; D004337:Drug Carriers / Q000737:chemistry*; D004705:Endocytosis; D005434:Flow Cytometry / Q000379:methods*; D005456:Fluorescent Dyes / Q000737:chemistry; D006367:HeLa Cells; D006801:Humans; D018613:Microscopy, Confocal; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D055672:Static Electricity
chemical_list: C095489:4,4-difluoro-4-bora-3a,4a-diaza-s-indacene; D001896:Boron Compounds; D004337:Drug Carriers; D005456:Fluorescent Dyes; D019904:Polymethyl Methacrylate
keywords: absolut quantitation; confocal laser scanning microscopy; flow cytometry; intracellular uptake; nanoparticles