RESUMO
AIM: Determination of the physicochemical parameters governing growth factors (GFs) adsorption and release from mesoporous calcium phosphate ceramics. MATERIALS & METHODS: Six mesoporous calcium phosphate ceramics prepared by soft and hard templating were loaded with two different physiological concentrations of TGF-ß1 or VEGF165 and their in vitro kinetics of adsorption/release were studied. RESULTS: This low GF loading promotes adsorption on the highest binding sites. The usually encountered detrimental burst release is thus considerably reduced for samples prepared by hard-templating method. CONCLUSION: Our findings highlight that the strong affinity of GFs with the ceramic surfaces, demonstrated by a slow GFs release, is enhanced by the large surface area, confinement into mesopores of ceramics and high difference of surface charge between ceramic surfaces and GFs.
Assuntos
Substitutos Ósseos/química , Fosfatos de Cálcio/síntese química , Portadores de Fármacos/síntese química , Fator de Crescimento Transformador beta1/química , Fator A de Crescimento do Endotélio Vascular/química , Adsorção , Materiais Biocompatíveis/síntese química , Regeneração Óssea/efeitos dos fármacos , Substitutos Ósseos/metabolismo , Cerâmica/síntese química , Liberação Controlada de Fármacos , Humanos , Porosidade , Propriedades de Superfície , Fator de Crescimento Transformador beta1/farmacologia , Fator A de Crescimento do Endotélio Vascular/farmacologiaRESUMO
AIM: To discriminate the most important physicochemical parameters for bone reconstruction, the inflammatory potential of seven nanoporous hydroxyapatite powders synthesized by hard or soft templating was evaluated both in vitro and in vivo. MATERIALS & METHODS: After physical and chemical characterization of the powders, we studied the production of inflammatory mediators by human primary monocytes after 4 and 24 h in contact with powders, and the host response after 2 weeks implantation in a mouse critical size defect model. RESULTS: In vitro results highlighted increases in the secretion of TNF-α, IL-1, -8, -10 and proMMP-2 and -9 and decreases in the secretion of IL-6 only for powders prepared by hard templating. In vivo observations confirmed an extensive inflammatory tissue reaction and a strong resorption for the most inflammatory powder in vitro. CONCLUSION: These findings highlight that the most critical physicochemical parameters for these nanoporous hydroxyapatite are, the crystallinity that controls dissolution potential, the specific surface area and the size and shape of crystallites.