title: Multiple three-dimensional mammalian cell aggregates formed away from solid substrata in ultrasound standing waves.
abstract: Single and multiple three-dimensional cell aggregates of human red blood cells (RBCs) and HepG2 cells were formed rapidly in low mega-Hertz ultrasound standing wave fields of different geometries. A single discoid aggregate was formed in a half-wavelength pathlength resonator at a cell concentration sufficient to produce a 3D structure. Multiple cell aggregates were formed on the axis of a cylindrical resonator with a plane transducer (discoid aggregates); in a resonator with a tubular transducer and in the cross-fields of plane and tubular transducers and two plane orthogonal transducers (all cylindrical aggregates). Mechanically strong RBC aggregates were obtained by crosslinking with wheat germ agglutinin (WGA, a lectin). Scanning electron microscopy showed aggregate surface porous structures when RBCs were mixed with WGA before sonication and tighter packing when ultrasonically preformed aggregates were subsequently exposed to a flow containing WGA. HepG2 cell aggregates showed strong accumulation of F-actin at sites of cell-cell contact consistent with increased mechanical stability. The aggregates had a porous surface, and yet confocal microscopy revealed a tight packing of cells in the aggregate's inner core.
authors.affiliation: School of Biosciences, Cardiff University, Cardiff CF10 3TL, UK. larisakuz@hotmail.com
authors.forename: Larisa A
authors.initials: LA
authors.lastname: Kuznetsova
authors.forename: Despina
authors.initials: D
authors.lastname: Bazou
authors.forename: Gareth O
authors.initials: GO
authors.lastname: Edwards
authors.forename: W Terence
authors.initials: WT
authors.lastname: Coakley
mesh_terms: D002449:Cell Aggregation; D018929:Cell Culture Techniques; D002460:Cell Line; D002477:Cells / Q000737:chemistry* / Q000648:ultrastructure; D002478:Cells, Cultured; D004912:Erythrocytes / Q000737:chemistry / Q000648:ultrastructure; D006801:Humans; D016062:Porosity; D013499:Surface Properties; D014465:Ultrasonics