title: Nanomechanical mapping of bone tissue regenerated by magnetic scaffolds.
abstract: Nanoindentation can provide new insights on the maturity stage of regenerating bone. The aim of the present study was the evaluation of the nanomechanical properties of newly-formed bone tissue at 4 weeks from the implantation of permanent magnets and magnetic scaffolds in the trabecular bone of rabbit femoral condyles. Three different groups have been investigated: MAG-A (NdFeB magnet + apatite/collagen scaffold with magnetic nanoparticles directly nucleated on the collagen fibers during scaffold synthesis); MAG-B (NdFeB magnet + apatite/collagen scaffold later infiltrated with magnetic nanoparticles) and MAG (NdFeB magnet). The mechanical properties of different-maturity bone tissues, i.e. newly-formed immature, newly-formed mature and native trabecular bone have been evaluated for the three groups. Contingent correlations between elastic modulus and hardness of immature, mature and native bone have been examined and discussed, as well as the efficacy of the adopted regeneration method in terms of "mechanical gap" between newly-formed and native bone tissue. The results showed that MAG-B group provided regenerated bone tissue with mechanical properties closer to that of native bone compared to MAG-A or MAG groups after 4 weeks from implantation. Further, whereas the mechanical properties of newly-formed immature and mature bone were found to be fairly good correlated, no correlation was detected between immature or mature bone and native bone. The reported results evidence the efficacy of nanoindentation tests for the investigation of the maturity of newly-formed bone not accessible through conventional analyses.
authors.affiliation: Laboratory of Nano-Biotechnologies (NaBi), Rizzoli Orthopaedic Institute, Via Gobetti 1/10, Bologna, 40136, Italy, m.bianchi@biomec.ior.it.
authors.forename: Michele
authors.initials: M
authors.lastname: Bianchi
authors.forename: Marco
authors.initials: M
authors.lastname: Boi
authors.forename: Maria
authors.initials: M
authors.lastname: Sartori
authors.forename: Gianluca
authors.initials: G
authors.lastname: Giavaresi
authors.forename: Nicola
authors.initials: N
authors.lastname: Lopomo
authors.forename: Milena
authors.initials: M
authors.lastname: Fini
authors.forename: Alek
authors.initials: A
authors.lastname: Dediu
authors.forename: Anna
authors.initials: A
authors.lastname: Tampieri
authors.forename: Maurilio
authors.initials: M
authors.lastname: Marcacci
authors.forename: Alessandro
authors.initials: A
authors.lastname: Russo
mesh_terms: D000818:Animals; D001031:Apatites / Q000737:chemistry; D001861:Bone Regeneration / Q000502:physiology*; D001842:Bone and Bones / Q000473:pathology*; D003094:Collagen / Q000737:chemistry; D055119:Elastic Modulus; D004548:Elasticity; D005269:Femur / Q000473:pathology; D060328:Magnetic Phenomena; D008280:Magnetics; D053758:Nanoparticles / Q000737:chemistry; D011312:Pressure; D011817:Rabbits; D013314:Stress, Mechanical; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds; D014783:Viscosity
chemical_list: D001031:Apatites; D003094:Collagen