title: Quantitative mechanics of endothelial phagocytosis of silicon microparticles.
abstract: Endothelia, once thought of as a barrier to the delivery of therapeutics, is now a major target for tissue-specific drug delivery. Tissue- and disease-specific molecular presentations on endothelial cells provide targets for anchoring or internalizing delivery vectors. Porous silicon delivery vectors are phagocytosed by vascular endothelial cells. The rapidity and efficiency of silicon microparticle uptake lead us to delineate the kinetics of internalization. To discriminate between surface-attached and -internalized microparticles, we developed a double fluorescent/FRET flow cytometric approach. The approach relies on quenching of antibody-conjugated fluorescein isothiocyanate covalently attached to the microparticle surface by attachment of a secondary antibody labeled with an acceptor fluorophore, phycoerythrin. The resulting half-time for microparticle internalization was 15.7 min, with confirmation provided by live confocal imaging as well as transmission electron microscopy.
authors.affiliation: Division of NanoMedicine, Department of Biomedical Engineering, University of Texas Health Science Center, Houston, Texas 77030, USA. rita.serda@uth.tmc.edu
authors.forename: Rita E
authors.initials: RE
authors.lastname: Serda
authors.forename: Jianhua
authors.initials: J
authors.lastname: Gu
authors.forename: Jared K
authors.initials: JK
authors.lastname: Burks
authors.forename: Kim
authors.initials: K
authors.lastname: Ferrari
authors.forename: Chiara
authors.initials: C
authors.lastname: Ferrari
authors.forename: Mauro
authors.initials: M
authors.lastname: Ferrari
mesh_terms: D002478:Cells, Cultured; D042783:Endothelial Cells / Q000502:physiology* / Q000648:ultrastructure; D005434:Flow Cytometry / Q000379:methods; D016650:Fluorescein-5-isothiocyanate / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D010316:Particle Size; D010587:Phagocytosis / Q000502:physiology*; D012825:Silicon / Q000737:chemistry / Q000378:metabolism*; D014471:Umbilical Veins / Q000166:cytology
chemical_list: D016650:Fluorescein-5-isothiocyanate; D012825:Silicon