title: Measuring the intravitreal mobility of nanomedicines with single-particle tracking microscopy.
abstract: OBJECTIVE
  To develop a robust assay to evaluate and compare the intravitreal mobility of nanoparticles in the intact vitreous body.
  
  
  METHODS
  Excised bovine eyes were prepared to preserve the fragile structure of the vitreous humor, while permitting high-resolution fluorescence microscopy and single-particle tracking analysis of intravitreally injected nanoparticles. This assay was validated by analyzing polystyrene beads and further employed to evaluate gene nanomedicines composed of poly(amido amine)s and plasmid DNA.
  
  
  RESULTS
  The assay was able to distinguish immobilized cationic nanoparticles from mobile PEGylated nanoparticles. PEGylation of the polyplexes resulted in a drastic improvement of their mobility.
  
  
  CONCLUSIONS
  An ex vivo eye model is presented for studying nanoparticle mobility in intact vitreous humor by single-particle tracking microscopy. These results give important guidelines for developing gene- and drug-delivery nanomedicines that are compatible with intravitreal administration.
authors: Laboratory for General Biochemistry & Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Harelbekestraat 72, 9000 Ghent, Belgium.
authors: Thomas F
authors: TF
authors: Martens
authors: Dries
authors: D
authors: Vercauteren
authors: Katrien
authors: K
authors: Forier
authors: Hendrik
authors: H
authors: Deschout
authors: Katrien
authors: K
authors: Remaut
authors: Rik
authors: R
authors: Paesen
authors: Marcel
authors: M
authors: Ameloot
authors: Johan Fj
authors: JF
authors: Engbersen
authors: Jo
authors: J
authors: Demeester
authors: Stefaan C
authors: SC
authors: De Smedt
authors: Kevin
authors: K
authors: Braeckmans
mesh_terms: D000818:Animals; D002417:Cattle; D004247:DNA / Q000008:administration & dosage; D058449:Intravitreal Injections; D008856:Microscopy, Fluorescence / Q000379:methods*; D050997:Nanomedicine; D053758:Nanoparticles / Q000008:administration & dosage* / Q000032:analysis*; D010957:Plasmids / Q000008:administration & dosage; D011092:Polyethylene Glycols / Q000008:administration & dosage / Q000032:analysis; D014822:Vitreous Body / Q000648:ultrastructure*
chemical_list: D011092:Polyethylene Glycols; D004247:DNA