title: Preparation and characterization of shape memory polymer scaffolds via solvent casting/particulate leaching.
abstract: OBJECTIVE
  Porous Shape Memory Polymers (SMPs) are ideal candidates for the fabrication of defect fillers, able to support tissue regeneration via minimally invasive approaches. In this regard, control of pore size, shape and interconnection is required to achieve adequate nutrient transport and cell ingrowth. Here, we assessed the feasibility of the preparation of SMP porous structures and characterized their chemico-physical properties and in vitro cell response.
  
  
  METHODS
  SMP scaffolds were obtained via solvent casting/particulate leaching of gelatin microspheres, prepared via oil/water emulsion. A solution of commercial polyether-urethane (MM-4520, Mitsubishi Heavy Industries) was cast on compacted microspheres and leached-off after polymer solvent evaporation. The obtained structures were characterized in terms of morphology (SEM and micro-CT), thermo-mechanical properties (DMTA), shape recovery behavior in compression mode, and in vitro cytocompatibility (MG63 Osteoblast-like cell line).
  
  
  RESULTS
  The fabrication process enabled easy control of scaffold morphology, pore size, and pore shape by varying the gelatin microsphere morphology. Homogeneous spherical and interconnected pores have been achieved together with the preservation of shape memory ability, with recovery rate up to 90%. Regardless of pore dimensions, MG63 cells were observed adhering and spreading onto the inner surface of the scaffolds obtained for up to seven days of static in vitro tests.
  
  
  CONCLUSIONS
  A new class of SMP porous structures has been obtained and tested in vitro: according to these preliminary results reported, SMP scaffolds can be further exploited in the design of a new class of implantable devices.
authors.affiliation: Department of Chemistry, Materials, and Chemical Engineering G. Natta, Politecnico di Milano, Milano, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: De Nardo
authors.forename: Serena
authors.initials: S
authors.lastname: Bertoldi
authors.forename: Alberto
authors.initials: A
authors.lastname: Cigada
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Tanzi
authors.forename: Håvard Jostein
authors.initials: HJ
authors.lastname: Haugen
authors.forename: Silvia
authors.initials: S
authors.lastname: Farè
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry* / Q000494:pharmacology; D002460:Cell Line; D048430:Cell Shape / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004655:Emulsions; D005780:Gelatin / Q000737:chemistry; D006801:Humans; D008863:Microspheres; D009821:Oils / Q000737:chemistry; D011108:Polymers / Q000737:chemistry* / Q000494:pharmacology; D016062:Porosity; D011312:Pressure; D012997:Solvents / Q000737:chemistry*; D013696:Temperature; D023822:Tissue Engineering; D014867:Water / Q000737:chemistry
chemical_list: D001672:Biocompatible Materials; D004655:Emulsions; D009821:Oils; D011108:Polymers; D012997:Solvents; D014867:Water; D005780:Gelatin