RESUMO
The interest in multifunctional biomaterials to be implanted are also able to release drugs that reduce pain and inflammation or prevent a possible infection has increased. Bioactive materials such as silica (SiO2) containing surface silanol groups contribute to the nucleation and growth of hydroxyapatite (HAp) in a physiological environment. Regarding biocompatibility, the spherical shape of particles is the desirable one, since it does not cause mechanical damage to the cell membrane. In this work, the synthesis of SiO2 microspheres was performed by the modified Stöber method and they were used for the biomimetic growth of HAp on their surface. The effect of the type of surfactant (sodium dodecyl sulphate (SDS), cetyltrimethylammonium bromide (CTAB), and polyethylene glycol (PEG)), and heat treatment on the morphology and size of SiO2 particles was investigated. Monodisperse, spherical-shaped SiO2 microparticles with an average particle size of 179 nm, were obtained when using PEG (SiO2-PEG). The biomimetic growth of HAp was performed on this sample to improve its biocompatibility and drug-loading capacity using gentamicin as a model drug. Biomimetic growth of HAp was confirmed by FTIR-ATR, SEM-EDX and TEM techniques. SiO2-PEG/HAp sample had a better biocompatibility in vitro and gentamicin loading capacity than SiO2-PEG sample.
RESUMO
Cellulose nanowhiskers (CNWs) with different surface composition were used to generate the biomimetic growth hydroxyapatite (HAp). Hybrids materials primarily consist of CNWs with HAp content below 24%. CNWs were produced by different inorganic acid hydrolyses to generate cellulose particles with surface groups to induce HAp mineralization. In the present study, we evaluate the use of CNWs prepared from hydrochloric acid, sulfuric acid and phosphoric acid. HAp growth was obtained from the biomimetic method using a simulated body fluid concentration of 1.5M (SBF). The sulfonate and phosphonate groups on the CNW surface have a direct impact on the nucleation and growth of HAp. HAp/CNW were also compared with the physical mixture method using HAp nanoparticles prepared by chemical precipitation. The bioactivity and biocompatibility of the hybrid materials were assessed by cell viability studies using fibroblast cells (L929). The materials obtained from the biomimetic method have superior biocompatibility/bioactivity compared to the material synthesized by the wet chemical precipitation method with an incubation period of 24h.