title: The influence of hydroxyapatite particles on in vitro degradation behavior of poly epsilon-caprolactone-based composite scaffolds.
abstract: The design of composite scaffolds with slow degradation kinetics imposes the assessment of the time-course of degradation to predict the long-term in vitro behavior. In this work, the effect of hydroxyapatite (HA) particles on the hydrolytic degradation of poly epsilon-caprolactone composite scaffold was investigated. The study of accelerated degradation mechanisms in alkaline medium enabled analysing comparable degradation profiles at different times. The accurate qualitative and quantitative study of morphology by scanning electron microscopy supported by image analysis demonstrated only a negligible effect on the structural porosity, to be ascribed to the addition of micrometric HA as a filler. Moreover, by comparing the Raman spectra with thermal analysis(thermogravimetry and differential scanning calorimetry) the role of HA on the composite degradation mechanism was defined, by separately quantifying the contribution of HA particles in the bulk and on the surface, on the bone formation as a function of modifications induced in the pore morphology, as well as physical and chemical properties of the polymer matrix. Indeed, HA particles alter the poly epsilon-caprolactone crystallinity inducing a "shielding" effect of the polymer matrix. Meanwhile, the slight reduction of pore size as a function of the increasing HA content and the improvement of the effective hydrophilicity of the scaffolds also influence the degradation by faster mechanisms. Finally, it has been proven that the presence of HA enhances the scaffold bioactivity and human osteoblast cell response, remarking the active role of bioactive signals on the promotion of the surface mineralization and, as a consequence, on the cell-material interaction.
authors.affiliation: Institute of Composite and Biomedical Materials, National Research Council, Naples, Italy. vguarino@unina.it
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Guarino
authors.forename: Paola
authors.initials: P
authors.lastname: Taddei
authors.forename: Michele
authors.initials: M
authors.lastname: Di Foggia
authors.forename: Concezio
authors.initials: C
authors.lastname: Fagnano
authors.forename: Gabriela
authors.initials: G
authors.lastname: Ciapetti
authors.forename: Luigi
authors.initials: L
authors.lastname: Ambrosio
mesh_terms: D020341:Absorbable Implants; D001672:Biocompatible Materials / Q000737:chemistry*; D001826:Body Fluids / Q000737:chemistry*; D049109:Cell Proliferation; D002470:Cell Survival; D002478:Cells, Cultured; D017886:Durapatite / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D010006:Osteoblasts / Q000166:cytology* / Q000502:physiology*; D010316:Particle Size; D011091:Polyesters / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D011091:Polyesters; C016240:polycaprolactone; D017886:Durapatite