title: Quantum dot agglomerates in biological media and their characterization by asymmetrical flow field-flow fractionation.
abstract: The molecular composition of the biological environment of nanoparticles influences their physical properties and changes their pristine physicochemical identity. In order to understand, or predict, the interactions of cells with specific nanoparticles, it is critical to know their size, shape, and agglomeration state not only in their nascent state but also in biological media. Here, we use asymmetrical flow field-flow fractionation (AF4) with on-line multiangle light scattering (MALS), dynamic light scattering (DLS) and UV-Visible absorption detections to determine the relative concentration of isolated nanoparticles and agglomerates in the case of three types of semi-conductor quantum dots (QDs) dispersed in Dulbecco's Modified Eagle Media (DMEM) containing 10% of fetal bovine serum (DMEM-FBS). AF4 analysis also yielded the size and size distribution of the agglomerates as a function of the time of QDs incubation in DMEM-FBS. The preferred modes of internalization of the QDs are assessed for three cell-types, N9 microglia, human hepatocellular carcinoma cells (HepG2) and human embryonic kidney cells (Hek293), by confocal fluorescence imaging of live cells, quantitative determination of the intracellular QD concentration, and flow cytometry. There is an excellent correlation between the agglomeration status of the three types of QDs in DMEM-FBS determined by AF4 analysis and their preferred mode of uptake by the three cell lines, which suggests that AF4 yields an accurate description of the nanoparticles as they encounter cells and advocates its use as a means to characterize particles under evaluation.
authors.affiliation: Department of Chemistry and Faculty Pharmacy, Université de Montréal, Montréal, Canada; Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Moquin
authors.affiliation: Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada.
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Neibert
authors.affiliation: Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada.
authors.forename: Dusica
authors.initials: D
authors.lastname: Maysinger
authors.affiliation: Department of Chemistry and Faculty Pharmacy, Université de Montréal, Montréal, Canada; WPI International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science, Tsukuba, Japan. Electronic address: francoise.winnik@umontreal.ca.
authors.forename: Françoise M
authors.initials: FM
authors.lastname: Winnik
mesh_terms: D002460:Cell Line; D045744:Cell Line, Tumor; D005434:Flow Cytometry; D031521:Fractionation, Field Flow / Q000379:methods; D057809:HEK293 Cells; D056945:Hep G2 Cells; D006801:Humans; D008027:Light; D017628:Microglia; D053758:Nanoparticles / Q000737:chemistry*; D045663:Quantum Dots / Q000737:chemistry*; D012542:Scattering, Radiation
keywords: Agglomeration state; Asymmetrical flow field-flow fractionation; Cell uptake; Cell viability; DLS; Nanoparticle; Zeta potential