title: Evaluation of structural and mechanical properties of electrospun nano-micro hybrid of poly hydroxybutyrate-chitosan/silk scaffold for cartilage tissue engineering.
abstract: BACKGROUND
  One of the new methods of scaffold fabrication is a nano-micro hybrid structure in which the properties of the scaffold are improved by introducing nanometer and micrometer structures. This method could be suitable for scaffold designing if some features improve.
  
  
  METHODS
  In this study, electrospun nanofibers of 9% weight solution of poly (3-hydroxybutyrate) (P3HB) and a 15% weight of chitosan by trifluoroacetic acid were coated on both the surface of a silk knitted substrate in the optimum condition to improve the mechanical properties of scaffolds for cartilage tissue engineering application. These hybrid nano-micro fibrous scaffolds were characterized by structural and mechanical evaluation methods.
  
  
  RESULTS
  Scanning electron microscopy values and porosity analysis showed that average diameter of nanofibers was 584.94 nm in electrospinning part and general porosity was more than 80%. Fourier transform infrared spectroscopy results indicated the presence of all elements without pollution. The tensile test also stated that by electrospinning, as well as adding chitosan, both maximum strength and maximum elongation increased to 187 N and 10 mm. It means that the microfibrous part of scaffold could affect mechanical properties of nano part of the hybrid scaffold, significantly.
  
  
  CONCLUSIONS
  It could be concluded that P3HB-chitosan/silk hybrid scaffolds can be a good candidate for cartilage tissue engineering.
authors.affiliation: Department of Biomaterials and Tissue Engineering, School of Advance Technology in Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Saeed
authors.initials: S
authors.lastname: Karbasi
authors.affiliation: Department of Biomaterials and Tissue Engineering, School of Advance Technology in Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Farnoosh
authors.initials: F
authors.lastname: Fekrat
authors.affiliation: Department of Textile Engineering, Isfahan University of Technology, Isfahan, Iran.
authors.forename: Daryoush
authors.initials: D
authors.lastname: Semnani
authors.affiliation: Department of Anatomical Sciences and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Shahnaz
authors.initials: S
authors.lastname: Razavi
authors.affiliation: Department of Textile Engineering, Isfahan University of Technology, Isfahan, Iran.
authors.forename: Elham Naghash
authors.initials: EN
authors.lastname: Zargar
keywords: Cartilage tissue engineering; chitosan; hybrid scaffold; poly (3-hydroxybutyrate); silk