title: Three-dimensional printed bone scaffolds: The role of nano/micro-hydroxyapatite particles on the adhesion and differentiation of human mesenchymal stem cells.
abstract: Bone tissue engineering is strongly dependent on the use of three-dimensional scaffolds that can act as templates to accommodate cells and support tissue ingrowth. Despite its wide application in tissue engineering research, polycaprolactone presents a very limited ability to induce adhesion, proliferation and osteogenic cell differentiation. To overcome some of these limitations, different calcium phosphates, such as hydroxyapatite and tricalcium phosphate, have been employed with relative success. This work investigates the influence of nano-hydroxyapatite and micro-hydroxyapatite (nHA and mHA, respectively) particles on the in vitro biomechanical performance of polycaprolactone/hydroxyapatite scaffolds. Morphological analysis performed with scanning electron microscopy allowed us to confirm the production of polycaprolactone/hydroxyapatite constructs with square interconnected pores of approximately 350 µm and to assess the distribution of hydroxyapatite particles within the polymer matrix. Compression mechanical tests showed an increase in polycaprolactone compressive modulus ( E) from 105.5 ± 11.2 to 138.8 ± 12.9 MPa (PCL_nHA) and 217.2 ± 21.8 MPa (PCL_mHA). In comparison to PCL_mHA scaffolds, the addition of nano-hydroxyapatite enhanced the adhesion and viability of human mesenchymal stem cells as confirmed by Alamar Blue assay. In addition, after 14 days of incubation, PCL_nHA scaffolds showed higher levels of alkaline phosphatase activity compared to polycaprolactone or PCL_mHA structures.
authors.affiliation: 1 School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, Manchester, UK.
authors.forename: Marco
authors.initials: M
authors.lastname: Domingos
authors.affiliation: 2 Institute of Polymers, Composites and Biomaterials, National Research Council of Italy, Naples, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Gloria
authors.affiliation: 3 CEMUC, Department of Chemical Engineering, University of Coimbra, Coimbra, Portugal.
authors.forename: Jorge
authors.initials: J
authors.lastname: Coelho
authors.affiliation: 1 School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, Manchester, UK.
authors.forename: Paulo
authors.initials: P
authors.lastname: Bartolo
authors.affiliation: 4 Universitat de Girona, Girona, Spain.
authors.forename: Joaquim
authors.initials: J
authors.lastname: Ciurana
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects*; D002454:Cell Differentiation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D017886:Durapatite / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D055595:Mechanical Phenomena; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects; D049329:Nanostructures / Q000737:chemistry*; D010012:Osteogenesis / Q000187:drug effects; D066330:Printing, Three-Dimensional; D023822:Tissue Engineering; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D017886:Durapatite; D000469:Alkaline Phosphatase
keywords: Biomanufacturing; bioactive materials; bone tissue engineering; hydroxyapatite; mesenchymal stem cells; scaffold development