Browsing by Author "Monteiro, F. J."
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- Influence of crystallite size of nanophased hydroxyapatite on fibronectin and osteonectin adsorption and on MC3T3-E1 osteoblast adhesion and morphologyPublication . Ribeiro, N.; Sousa, Susana R.; Monteiro, F. J.The characteristic topographical features (crystallite dimensions, surface morphology and roughness) of bioceramics may influence the adsorption of proteins relevant to bone regeneration. This work aims at analyzing the influence of two distinct nanophased hydroxyapatite (HA) ceramics, HA725 and HA1000 on fibronectin (FN) and osteonectin (ON) adsorption and MC3T3-E1 osteoblast adhesion and morphology. Both substrates were obtained using the same hydroxyapatite nanocrystals aggregates and applying the sintering temperatures of 725ºC and 1000ºC, respectively. The two proteins used in this work, FN as an adhesive glycoprotein and ON as a counter-adhesive protein, are known to be involved in the early stages of osteogenesis (cell adhesion, mobility and proliferation). The properties of the nanoHA substrates had an important role in the adsorption behavior of the two studied proteins and clearly affected the MC3T3- E1 morphology, distribution and metabolic activity. HA1000 surfaces presenting slightly larger grain size, higher root-mean-square roughness (Rq), lower surface area and porosity, allowed for higher amounts of both proteins adsorbed. These substrates also revealed increased number of exposed FN cell-binding domains as well as higher affinity for osteonectin. Regarding the osteoblast adhesion results, improved viability and cell number were found for HA1000 surfaces as compared to HA725 ones, independently of the presence or type of adsorbed protein. Therefore the osteoblast adhesion and metabolic activity seemed to be more sensitive to surfaces morphology and roughness than to the type of adsorbed proteins.
- Osteoclastogenic differentiation of human precursor cells over micro- and nanostructured hydroxyapatite topographyPublication . Costa-Rodrigues, Joao; Carmo, S.; Perpétuo, I. P.; Monteiro, F. J.; Fernandes, M. H.Background: Surface topography is a key parameter in bone cells–biomaterials interactions. This study analyzed the behavior of human osteoclast precursor cells cultured over three hydroxyapatite (HA) surfaces ranging from a micro- to nanoscale topography. Methods: HA surfaces were prepared with microsized HA particles, at 1300 °C (HA1), andwith nanosized HA particles at 1000 °C (HA2) and 830 °C (HA3). Human osteoclast precursorswere cultured in the absence or presence of M-SCF and RANKL. Results: HA surfaces had similar chemical composition, however, HA1 and HA3 presented typical micro- and nanostructured topographies, respectively, and HA2 profile was between those of HA1 and HA3. The decrease on the average grain diameter to the nanoscale range (HA3)was accompanied by an increase in surface area, porosity and hydrophilicity and a decrease in roughness. Compared to HA1 surface, HA3 allowed a lower osteoclastic adhesion, differentiation and function. Differences in the cell response appeared to be associated with the modulation of relevant intracellular signaling pathways. Conclusions: The decrease in HA grain size to a biomimetic nanoscale range, appears less attractive to osteoclastic differentiation and function, compared to the HA microsized topography. General significance: This observation emphasizes the role of surface topography in designing advanced biomaterials for tailored bone cells response in regenerative strategies.