title: Innovative macroporous granules of nanostructured-hydroxyapatite agglomerates: bioactivity and osteoblast-like cell behaviour.
abstract: To modulate the biological response of implantable granules, two types of bioactive porous granules composed of nanostructured-hydroxyapatite (HA) agglomerates and microstructured-HA, respectively, were prepared using a polyurethane sponge impregnation and burnout method. The resulting granules presented a highly porous structure with interconnected porosity. Both types of granules were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and mercury intrusion porosimetry. Results showed that nanostructed-HA granules presented higher surface area and porosity than microstructured-HA granules. In vitro testing using MG63 human osteoblast-like cells showed that on both types of surfaces cells were able to adhere, proliferate, and migrate through the macropores, and a higher growth rate was achieved on nanostructured-HA granules than on microstructured-HA granules (76 and 40%, respectively). In addition, these cells maintained similar expression levels of osteoblastic-associated markers namely collagen type I, alkaline phosphatase, bone morphogenetic protein-2, macrophage colony-stimulating factor, and osteoprotegerin. These innovative nanostructured-HA granules may be considered as promising bioceramic alternative matrixes for bone regeneration and drug release application.
authors.affiliation: Divisão de Biomateriais, INEB-Instituto de Engenharia Biomédica, Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal.
authors.forename: M S
authors.initials: MS
authors.lastname: Laranjeira
authors.forename: M H
authors.initials: MH
authors.lastname: Fernandes
authors.forename: F J
authors.initials: FJ
authors.lastname: Monteiro
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D002478:Cells, Cultured; D017886:Durapatite / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D049329:Nanostructures / Q000737:chemistry*; D010006:Osteoblasts / Q000166:cytology / Q000502:physiology*; D011140:Polyurethanes / Q000737:chemistry; D016062:Porosity; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
chemical_list: D001672:Biocompatible Materials; D015415:Biomarkers; D011140:Polyurethanes; D017886:Durapatite