title: Surface modification of a POSS-nanocomposite material to enhance cellular integration of a synthetic bioscaffold.
abstract: Polyhedral oligomeric silsesquioxane poly(carbonate-urea) urethane (POSS-PCU) is a versatile nanocomposite biomaterial with growing applications as a bioscaffold for tissue engineering. Integration of synthetic implants with host tissue can be problematic but could be improved by topographical modifications. We describe optimization of POSS-PCU by dispersion of porogens (sodium bicarbonate (NaHCO3), sodium chloride (NaCl) and sucrose) onto the material surface, with the principle aim of increasing surface porosity, thus providing additional opportunities for improved cellular and vascular ingrowth. We assess the effect of the porogens on the material's mechanical strength, surface chemistry, wettability and cytocompatibilty. Surface porosity was characterized by scanning electron microscopy (SEM). There was no alteration in surface chemistry and wettability and only modest changes in mechanical properties were detected. The size of porogens correlated well with the porosity of the construct produced and larger porogens improved interconnectivity of spaces within constructs. Using primary human bronchial epithelial cells (HBECs) we demonstrate moderate in vitro cytocompatibility for all surface modifications; however, larger pores resulted in cellular aggregation. These cells were able to differentiate on POSS-PCU scaffolds. Implantation of the scaffold in vivo demonstrated that larger pore sizes favor cellular integration and vascular ingrowth. These experiments demonstrate that surface modification with large porogens can improve POSS-PCU nanocomposite scaffold integration and suggest the need to strike a balance between the non-porous surfaces required for epithelial coverage and the porous structure required for integration and vascularization of synthetic scaffolds in future construct design.
authors.affiliation: Lungs for Living Research Centre, UCL Respiratory, University College London, London, UK; UCL Centre of Nanotechnology and Regenerative Medicine, Division of Surgery and Interventional Science, Royal Free London NHS Foundation Trust Hospital and University College London, London, UK.
authors.forename: Claire
authors.initials: C
authors.lastname: Crowley
authors.affiliation: UCL Centre of Nanotechnology and Regenerative Medicine, Division of Surgery and Interventional Science, Royal Free London NHS Foundation Trust Hospital and University College London, London, UK.
authors.forename: Poramate
authors.initials: P
authors.lastname: Klanrit
authors.affiliation: Lungs for Living Research Centre, UCL Respiratory, University College London, London, UK.
authors.forename: Colin R
authors.initials: CR
authors.lastname: Butler
authors.affiliation: Lungs for Living Research Centre, UCL Respiratory, University College London, London, UK.
authors.forename: Aikaterini
authors.initials: A
authors.lastname: Varanou
authors.affiliation: Lungs for Living Research Centre, UCL Respiratory, University College London, London, UK; Centre for Inflammation and Tissue Repair, UCL Respiratory, University College London, London, UK.
authors.forename: Manuela
authors.initials: M
authors.lastname: Platé
authors.affiliation: Lungs for Living Research Centre, UCL Respiratory, University College London, London, UK.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Hynds
authors.affiliation: Centre for Inflammation and Tissue Repair, UCL Respiratory, University College London, London, UK.
authors.forename: Rachel C
authors.initials: RC
authors.lastname: Chambers
authors.affiliation: UCL Centre of Nanotechnology and Regenerative Medicine, Division of Surgery and Interventional Science, Royal Free London NHS Foundation Trust Hospital and University College London, London, UK.
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Seifalian
authors.affiliation: UCL Ear Institute, Royal National Throat Nose and Ear Hospital and University College London, London, UK. Electronic address: m.birchall@ucl.ac.uk.
authors.forename: Martin A
authors.initials: MA
authors.lastname: Birchall
authors.affiliation: Lungs for Living Research Centre, UCL Respiratory, University College London, London, UK. Electronic address: s.janes@ucl.ac.uk.
authors.forename: Sam M
authors.initials: SM
authors.lastname: Janes
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry / Q000494:pharmacology*; D002448:Cell Adhesion / Q000187:drug effects; D016923:Cell Death / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004847:Epithelial Cells / Q000166:cytology* / Q000187:drug effects*; D000431:Ethanol / Q000494:pharmacology; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D020007:Implants, Experimental; D008810:Mice, Inbred C57BL; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure; D018919:Neovascularization, Physiologic / Q000187:drug effects; D017646:Organosilicon Compounds / Q000737:chemistry* / Q000494:pharmacology*; D010539:Permeability; D016062:Porosity; D013395:Sucrose / Q000494:pharmacology; D013499:Surface Properties; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D017646:Organosilicon Compounds; D000431:Ethanol; D013395:Sucrose
keywords: Biocompatible materials; Nanocomposites; Porosity; Re-epithelialization; Tissue engineering; Trachea