This is an author's version published in: http://oatao.univ-toulouse.fr/25565 ABSTRACT: Multifunctionalized biomaterials with enhanced bone antiresorptive properties were obtained through adso rp tion of a bisphosphonate, risedronate, on hydroxyapatite (HA) nanocrystals functionalized with zinc ions and polyethylenimine (PEI). Zn incorporation into the HA structure amounts to about 8 a tom %, whereas the PEI content of the bifunctionalized material ZnHAPEIBP is about 5.9 wt %. The mechanism of

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... dsorption and release of the bisphosphonate on ZnHAPEI is compared with that on ZnHA risedronate adsorption isotherm on ZnHA is a Lan gm uir type, whereas the isotherm of adso rp tion on ZnHAPEI is better fitted with a Freundlich mode! and involved a higher amount of adsorbed risedronate. ln vitro ce!! tests were carried out with a coculture mode! of osteoblasts and osteoclasts using a mode! simulating oxidative stress and consequent cellular senescence and osteoporosis by the addition of H 2 0 2 . The conditions utilized in the coculture mode! strongly affect osteoblast behavior. The results show that the composite materials allow an increase in osteoblast viability and recover impairment, revealing a nove! characteristic of risedronate that is able to counteract the negative effects of oxidative stress when associated with differently functionalized samples. Both PEI and the bisphosphonate reduce osteoclast viability. Moreover, PEI, and even more risedronate, exerts an inhibitory effect on osteoclast activity.