The effect of reduction of graphene oxide on the formation of hydroxyapatite and tricalcium phosphate

This study reports on biomimetic mineralization route employing reduced graphene oxide (RGO) at different rates as a template material for biomineralization of biphasic hydroxyapatite/tricalcium phosphate (HAP/TCP). RGO-HAP/TCP hybride composites were synthesized via biomineralization in Simulated Body Fluid (SBF). GO was prepared from pristine graphite by Hummers and Offeman method. GO nanoparticles were reduced with sodium borohydride (NaBH4) before soaking in 5xSBF for 3 weeks at 37 °C and 7.4 pH to performing biomineralization. Surface area and average size distribution of fabricated GO were found as 813.2 m2 g-1 and 1.2968 μm by using BET and DLS technique, respectively. All surfaces are overall negatively charged and zeta potentials of GO, R1GO, R2GO, R3GO were found to be −35.05, −30.01, 29.5, −29.01 and −28.9, respectively in the neutral pH. The contact angles of GO, R1GO, R2GO and R3GO are 33.5°, 55.3°, 57.4° and 61.1°, respectively. The ID/IG values determined by Raman are 1.07, 1.04, 1.02 and 1.01 for GO, R1GO, R2GO and R3GO, respectively. After the reduction, its maximum peak at 236 was clearly shifted to 260, 264 and 267 nm for R1GO, R2GO and R3GO. The precipitation of biphasic HAP/TCP on R1GO and R2GO was confirmed by XRD, FTIR and TGA analysis.