title: A novel cell-based microfluidic multichannel setup-impact of hydrodynamics and surface characteristics on the bioadhesion of polystyrene microspheres.
abstract: Carboxylated polystyrene microspheres with 1 μm in diameter were surface-modified either by coating with poly(ethyleneimine) (PEI) as cationic polyelectrolyte leading to a conversion of the surface charge from negative to positive, or by covalent immobilization of wheat germ agglutinin (WGA) via a carbodiimide method to obtain a carbohydrate specific biorecognitive surface. To characterize the impact of the binding mechanism on the particle-cell interaction, the binding efficiencies to Caco-2 cells were investigated for both, the biorecognitive WGA-grafted particles and the positively charged PEI-microspheres, and compared to the unmodified negatively charged polystyrene particles. As a result, WGA-grafted particles exhibited the highest binding rates to single cells as well as monolayers as compared to positive and negative particles under stationary conditions. Concerning ionic interactions, PEI-coated particles suffered from a critical agglomeration tendency leading to a high variance in cell binding. Furthermore, in order to elucidate the bioadhesive properties under flow conditions, an acoustically-driven microfluidic multichannel system was applied. Using different setups, it could be demonstrated that the hydrodynamics exerted almost no impact on cell-bound particles with a size of 1 μm at a flow velocity of 2000 μm s(-1). Using this novel microfluidic system, it was thus possible to prove that the omnipresent hydrodynamic drag in vivo is mostly negligible for microparticulate drug delivery systems in the size range of 1 μm or below.
authors.affiliation: Department of Pharmaceutical Technology and Biopharmaceutics, University of Vienna, Vienna, Austria.
authors.forename: Xue-Yan
authors.initials: XY
authors.lastname: Wang
authors.forename: Clara
authors.initials: C
authors.lastname: Pichl
authors.forename: Franz
authors.initials: F
authors.lastname: Gabor
authors.forename: Michael
authors.initials: M
authors.lastname: Wirth
mesh_terms: D018938:Caco-2 Cells; D004337:Drug Carriers / Q000737:chemistry; D006801:Humans; D057446:Hydrodynamics; D044085:Microfluidics / Q000379:methods*; D008863:Microspheres; D011137:Polystyrenes / Q000737:chemistry*; D014909:Wheat Germ Agglutinins / Q000737:chemistry
chemical_list: D004337:Drug Carriers; D011137:Polystyrenes; D014909:Wheat Germ Agglutinins