Silicon dioxide nanoparticles decorated on graphene oxide nanosheets and their application in poly(L-lactic acid) scaffold

Introduction: The aggregation of graphene oxide (GO) is considered as main challenge, although GO possesses excellent mechanical properties which arouses widespread attention as reinforcement for polymers. Objectives: In this study, silicon dioxide (SiO₂) nanoparticles were decorated onto surface of GO nanosheets through in situ growth method for promoting dispersion of GO in poly(L-lactic acid) (PLLA) bone scaffold. Methods: Hydroxyl and carboxyl functional groups of GO provided sites for SiO₂ nucleation, and SiO₂ grew with hydrolysis and polycondensation of tetraethyl orthosilicate (TEOS) and finally formed nanoparticles onto surface of GO with covalent bonds. Then, the GO@ SiO₂ nanocomposite was blended with PLLA for the fabrication of bone scaffold by selective laser sintering (SLS). Result: The results indicated that the obtained SiO₂ were distributed relatively uniformly on surface of GO under TEOS concentration of 0.10 mol/L (GO@SiO₂-10), and the covering of SiO₂ on GO could increase interlayer distance of GO nanosheets from 0.799 nm to 0.894 nm, thus reducing van der Waals forces between GO nanosheets and facilitating the dispersion. Tensile and compressive strength of scaffold containing GO@SiO₂ hybrids were significantly enhanced, especially for the scaffold containing GO@SiO₂-10 hybrids with enhancement of 30.95 % in tensile strength and 66.33 % in compressive strength compared with the scaffold containing GO. Additionally, cell adhesion and fluorescence experiments demonstrated excellent cytocompatibility of the scaffold. Conclusions: The good dispersion of GO@SiO₂ enhances the mechanical properties and cytocompatibility of scaffold, making it a potential candidate for bone tissue engineering applications.