title: Moldable elastomeric polyester-carbon nanotube scaffolds for cardiac tissue engineering.
abstract: Polymer biomaterials are used to construct scaffolds in tissue engineering applications to assist in mechanical support, organization, and maturation of tissues. Given the flexibility, electrical conductance, and contractility of native cardiac tissues, it is desirable that polymeric scaffolds for cardiac tissue regeneration exhibit elasticity and high electrical conductivity. Herein, we developed a facile approach to introduce carbon nanotubes (CNTs) into poly(octamethylene maleate (anhydride) 1,2,4-butanetricarboxylate) (124 polymer), and developed an elastomeric scaffold for cardiac tissue engineering that provides electrical conductivity and structural integrity to 124 polymer. 124 polymer-CNT materials were developed by first dispersing CNTs in poly(ethylene glycol) dimethyl ether porogen and mixing with 124 prepolymer for molding into shapes and crosslinking under ultraviolet light. 124 polymers with 0.5% and 0.1% CNT content (wt) exhibited improved conductivity against pristine 124 polymer. With increasing the CNT content, surface moduli of hybrid polymers were increased, while their bulk moduli were decreased. Furthermore, increased swelling of hybrid 124 polymer-CNT materials was observed, suggesting their improved structural support in an aqueous environment. Finally, functional characterization of engineered cardiac tissues using the 124 polymer-CNT scaffolds demonstrated improved excitation threshold in materials with 0.5% CNT content (3.6±0.8V/cm) compared to materials with 0% (5.1±0.8V/cm) and 0.1% (5.0±0.7V/cm), suggesting greater tissue maturity. 124 polymer-CNT materials build on the advantages of 124 polymer elastomer to give a versatile biomaterial for cardiac tissue engineering applications.
  
  
  
  Achieving a high elasticity and a high conductivity in a single cardiac tissue engineering material remains a challenge. We report the use of CNTs in making electrically conductive and mechanically strong polymeric scaffolds in cardiac tissue regeneration. CNTs were incorporated in elastomeric polymers in a facile and reproducible approach. Polymer-CNT materials were able to construct complicated scaffold structures by injecting the prepolymer into a mold and crosslinking the prepolymer under ultraviolet light. CNTs enhanced electrical conductivity and structural support of elastomeric polymers. Hybrid polymeric scaffolds containing 0.5wt% CNTs increased the maturation of cardiac tissues fabricated on them compared to pure polymeric scaffolds. The cardiac tissues on hybrid polymer-CNT scaffolds showed earlier beating than those on pure polymer scaffolds. In the future, fabricated polymer-CNT scaffolds could also be used to fabricate other electro-active tissues, such neural and skeletal muscle tissues. In the future, fabricated polymer-CNT scaffolds could also be used to fabricate other electro-active tissues, such as neural and skeletal muscle tissues.
authors.affiliation: Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Samad
authors.initials: S
authors.lastname: Ahadian
authors.affiliation: Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada; Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Locke
authors.initials: L
authors.lastname: Davenport Huyer
authors.affiliation: Ceramics Processing Group, Research Center for Functional Materials, National Institute for Materials Science (NIMS), Tsukuba, Japan.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Estili
authors.affiliation: Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Bess
authors.initials: B
authors.lastname: Yee
authors.affiliation: Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Nathaniel
authors.initials: N
authors.lastname: Smith
authors.affiliation: Advanced Micro and Nanosystems Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Zhensong
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Advanced Micro and Nanosystems Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Yu
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada; Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada. Electronic address: m.radisic@utoronto.ca.
authors.forename: Milica
authors.initials: M
authors.lastname: Radisic
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000138:chemical synthesis; D002478:Cells, Cultured; D055119:Elastic Modulus; D020724:Elastomers / Q000737:chemistry*; D004553:Electric Conductivity; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008422:Materials Testing; D032383:Myocytes, Cardiac / Q000166:cytology / Q000502:physiology*; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D011091:Polyesters / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013314:Stress, Mechanical; D013718:Tensile Strength; D023822:Tissue Engineering / Q000295:instrumentation* / Q000379:methods; D054457:Tissue Scaffolds
chemical_list: D001672:Biocompatible Materials; D020724:Elastomers; D037742:Nanotubes, Carbon; D011091:Polyesters
keywords: Carbon nanotubes; Cardiac tissue engineering; Elastomer; Electrical conductivity; Maturation; Scaffold