title: Biodegradable polymer film as a source for formation of human fetal retinal pigment epithelium spheroids.
abstract: OBJECTIVE
  To evaluate the attachment of human fetal rctinal pigment epithelial (HFRPE) cells to a biodegradable polymer film with subsequent formation of spheroids in vitro.
  
  
  METHODS
  Ten biodegradable polymer films with different compositions were examined for their physical properties and ease of manipulation under a dissecting microscope. The film with the most suitable handling characteristics was chosen, and a purely isolated sheet of HFRPE cells was attached to it. The purity of the cells was assessed by their pigmentation and expression of cytokeratin. Proliferation was assessed by incorporation of 5-bromo-2'-deoxyuridine (BrdtJ). Cellular structure was analyzed under light and electron microscopes, and the functional capability of the cells was evaluated by rod outer segment (ROS) phagocytosis.
  
  
  RESULTS
  The polymer film with composition 50:50 poly (DL-lactide) (PLA)/poly (DL-lactide-co-glycolide) (PLG) with an inherent viscosity of 1.03 dl/g was found to be the most suitable for handling under the microscope. Sheets of HFRPE cells attached to the polymer films within 48 hours and began to form spheroids. All the isolated cells were pigmented and expressed cytokeratin. They possessed a cuboidal morphology, numerous apical microvilli, and no sign of dedifferentiation. HFRPE cells produced extracellular matrix (collagen filaments) on their basal side, filling the cavities of the polymer film. The cells subsequently proliferated, incorporated BrdU, migrated onto the culture plate to form monolayers, and phagocytized ROS.
  
  
  CONCLUSIONS
  Biodegradable polymer films can be used as a scaffold for the adhesion of the HFRPE sheet and formation of spheroids. Spheroids represent a source of high density and well-differentiated HFRPE cells that are easy to transfer. Furthermore, the stricture of the membrane makes it suitable for additional applications.
authors.affiliation: Department of Ophthalmology and Visual Science, University of Chicago, Illinois 60637, USA.
authors.forename: K A
authors.initials: KA
authors.lastname: Rezai
authors.forename: L
authors.initials: L
authors.lastname: Farrokh-Siar
authors.forename: M L
authors.initials: ML
authors.lastname: Botz
authors.forename: K C
authors.initials: KC
authors.lastname: Godowski
authors.forename: D D
authors.initials: DD
authors.lastname: Swanbom
authors.forename: S C
authors.initials: SC
authors.lastname: Patel
authors.forename: J T
authors.initials: JT
authors.lastname: Ernest
mesh_terms: D001673:Biodegradation, Environmental; D002455:Cell Division / Q000502:physiology; D002478:Cells, Cultured; D005333:Fetus / Q000166:cytology / Q000502:physiology*; D006801:Humans; D009040:Motion Pictures; D010587:Phagocytosis / Q000502:physiology; D010857:Pigment Epithelium of Eye / Q000166:cytology / Q000196:embryology*; D011108:Polymers; D018874:Spheroids, Cellular / Q000502:physiology*
chemical_list: D011108:Polymers