title: Nanoparticle tethered antioxidant response element as a biosensor for oxygen induced toxicity in retinal endothelial cells.
abstract: OBJECTIVE
  A novel system, based on biosensor DNA tethered to a nanoparticle, was developed for the treatment of retinopathy of prematurity.
  
  
  METHODS
  The construction of a five-layered nanoparticle was visualized with gel electrophoresis. Transcriptionally active PCR products (TAP) containing the biosensor sequence, were bioconjugated to the surface of magnetic nanoparticles yielding biosensor tethered magnetic nanoparticles (MNP). The biosensor was based on an enhanced green fluorescent protein (EGFP) reporter gene driven by an enhanced antioxidant response element (ARE). Image analysis and flow cytometry were used to characterize MNP delivery and biosensor activity.
  
  
  RESULTS
  The MNP penetrated dividing and migrating cells more often than quiescent endothelial cells in a wound-healing in vitro assay. Prussian blue staining demonstrated that more cells have nanoparticle cores than are transfected. When compared to naked TAP alone, MNP transfected more cells in a dose dependent manner. Both the biosensor alone and MNP induce gene expression in the presence of hyperoxia, greater than 1.5 fold over normoxic controls. These data also show that the MNP had a signal to noise ratio of 0.5 greater than the plasmid form of the biosensor as demonstrated by flow cytometry.
  
  
  CONCLUSIONS
  This approach has the potential to allow the endothelial cells of the retinal vasculature to prevent or treat themselves after hyperoxic insult, rather than systemic treatment to protect or treat only the retina.
authors.affiliation: The Wilmer Ophthalmological Institute, Department of Ophthalmology, The Johns Hopkins Hospital, Baltimore, MD 21287-9115, USA. tprow1@jhmi.edu
authors.forename: Tarl
authors.initials: T
authors.lastname: Prow
authors.forename: Rhonda
authors.initials: R
authors.lastname: Grebe
authors.forename: Carol
authors.initials: C
authors.lastname: Merges
authors.forename: Jacob N
authors.initials: JN
authors.lastname: Smith
authors.forename: D Scott
authors.initials: DS
authors.lastname: McLeod
authors.forename: James F
authors.initials: JF
authors.lastname: Leary
authors.forename: Gerard A
authors.initials: GA
authors.lastname: Lutty
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D015374:Biosensing Techniques; D002478:Cells, Cultured; D004285:Dogs; D042783:Endothelial Cells / Q000187:drug effects*; D015870:Gene Expression; D017930:Genes, Reporter; D018496:Hyperoxia / Q000235:genetics; D008280:Magnetics; D049329:Nanostructures; D010100:Oxygen / Q000506:poisoning*; D020218:Response Elements / Q000235:genetics; D012171:Retinal Vessels / Q000187:drug effects*; D014162:Transfection
chemical_list: D000975:Antioxidants; D010100:Oxygen