title: Antibacterial activity and biocompatibility of three-dimensional nanostructured porous granules of hydroxyapatite and zinc oxide nanoparticles--an in vitro and in vivo study.
abstract: Ceramic scaffolds are widely studied in the bone tissue engineering field due to their potential in regenerative medicine. However, adhesion of microorganisms on biomaterials with subsequent formation of antibiotic-resistant biofilms is a critical factor in implant-related infections. Therefore, new strategies are needed to address this problem. In the present study, three-dimensional and interconnected porous granules of nanostructured hydroxyapatite (nanoHA) incorporated with different amounts of zinc oxide (ZnO) nanoparticles were produced using a simple polymer sponge replication method. As in vitro experiments, granules were exposed to Staphylococcus aureus and Staphylococcus epidermidis and, after 24 h, the planktonic and sessile populations were assessed. Cytocompatibility towards osteoblast-like cells (MG63 cell line) was also evaluated for a period of 1 and 3 days, through resazurin assay and imaging flow cytometry analysis. As in vivo experiments, nanoHA porous granules with and without ZnO nanoparticles were implanted into the subcutaneous tissue in rats and their inflammatory response after 3, 7 and 30 days was examined, as well as their antibacterial activity after 1 and 3 days of S. aureus inoculation. The developed composites proved to be especially effective at reducing bacterial activity in vitro and in vivo for a weight percentage of 2% ZnO, with a low cell growth inhibition in vitro and no differences in the connective tissue growth and inflammatory response in vivo. Altogether, these results suggest that nanoHA-ZnO porous granules have a great potential to be used in orthopaedic and dental applications as a template for bone regeneration and, simultaneously, to restrain biomaterial-associated infections.
authors.affiliation: Faculdade de Engenharia, Departamento de Engenharia Metalúrgica e Materiais, Universidade do Porto, Rua Dr Roberto Frias, s/n 4200-465 Porto, Portugal. i3s-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal. INEB-Instituto de Engenharia Biomédica, Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal.
authors.forename: L
authors.initials: L
authors.lastname: Grenho
authors.forename: C L
authors.initials: CL
authors.lastname: Salgado
authors.forename: M H
authors.initials: MH
authors.lastname: Fernandes
authors.forename: F J
authors.initials: FJ
authors.lastname: Monteiro
authors.forename: M P
authors.initials: MP
authors.lastname: Ferraz
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001672:Biocompatible Materials / Q000633:toxicity*; D002460:Cell Line; D017886:Durapatite / Q000737:chemistry; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D053758:Nanoparticles / Q000737:chemistry* / Q000382:microbiology*; D058608:Nanopores / Q000648:ultrastructure; D010006:Osteoblasts / Q000187:drug effects / Q000382:microbiology*; D016062:Porosity; D051381:Rats; D017208:Rats, Wistar; D013203:Staphylococcal Infections; D015034:Zinc Oxide / Q000737:chemistry / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D001672:Biocompatible Materials; D017886:Durapatite; D015034:Zinc Oxide