Biocompatibility and bioactivity of porous polymer-derived Ca-Mg silicate ceramics

摘要

Magnesium is a trace element in the human body, known to have important effects on cell differentiation and the mineralisation of calcified tissues. This study aimed to synthesise highly porous Ca-Mg silicate foamed scaffolds from preceramic polymers, with analysis of their biological response. Akermanite (Ak) and wollastonite-diopside (WD) ceramic foams were obtained from the pyrolysis of a liquid silicone mixed with reactive fillers. The porous structure was obtained by controlled water release from selected fillers (magnesium hydroxide and borax) at 350 degrees C. The homogeneous distribution of open pores, with interconnects of modal diameters of 160-180 mu m was obtained and maintained after firing at 1100 degrees C. Foams, with porosity exceeding 80%, exhibited compressive strength values of 1-2 MPa. In vitro studies were conducted by immersion in SBF for 21 days, showing suitable dissolution rates, pH and ionic concentrations. Cytotoxicity analysis performed in accordance with IS010993-5 and IS010993-12 standards confirmed excellent biocompatibility of both Ak and WD foams. In addition, MC3T3-E1 cells cultured on the Mg-containing scaffolds demonstrated enhanced osteogenic differentiation and the expression of osteogenic markers including Collagen Type I, Osteopontin and Osteocalcin, in comparison to Mg-free counterparts. The results suggest that the addition of magnesium can further enhance the bioactivity and the potential for bone regeneration applications of Ca-silicate materials.