Multilayered Tissue-engineered Construct Based on Biodegradable and Biocompatible Materials for Injured Biliary Tract Repair

Design of bioengineered organs is still complicated due to the lack of understanding of biological mechanisms that stimulate physiologically relevant conditions and induce relevant cellular media. Systematic review identified qualitative and quantitative requirements for tissue-engineered construct of the common bile duct. Tissue-specific approach was used to select materials, biologics, and cells for creation of physiologically relevant construct for injured biliary tract repair. Samples of fibrous scaffolds from PCL, PGLA, PLCL, and cellulose diacetate were created by electrospinning method and evaluated with MTT assay for cytotoxicity assessment. Mechanical properties of human bile duct sample and fibrous scaffolds were evaluated for Young's modulus and for percentage of elongation. Mechanical properties of fibrous materials were evaluated in vitro during degradation and erosion in various media. Fibrous PCL-scaffolds were formed by emulsion electrospinning with incorporation of following biomolecules: Neovasculgen gene-therapy drug (VEGF165 plasmid), EGF and GFP. The fluorescent microscopy of fibers confirmed volume modification by biomolecules. ELISA-test confirmed prolonged exit of EGF biomolecules from PCL-scaffold in vitro. Implantation of Neovasculgen-modified PCL-scaffold in rats showed vascular density increase in the implantation zone. Experimental swine model of iatrogenic bile duct injury was created and follow-up implantation of tubular fibrous PCL-scaffold in porcine bile duct showed a tissue-specific physiological biocompatibility of fibrous PCL. Fibrous three-layered scaffolds from PCL and PLCL/PLGA were obtained by electrospinning method and were tested for mechanical properties. The sample of three-layered scaffold from modified fibrous PCL and PLGA with incorporation of EGF and Neovasculgen was two-side seeded with bone marrow-derived mesenchymal stem cells and bile duct epithelial cells to obtain the tissue-engineered construct.