Bandgap and visible-light-induced photocatalytic performance and dye degradation of silver doped HAp/TiO2 nanocomposite by sol-gel method and its antimicrobial activity

Silver doped hydroxyapatite and titanium oxide nanocomposites have been obtained by sol-gel techniques with novel antimicrobial activities for biomedical applications. The synthesis of Ca10-X AgX (PO4)6(OH)2 along with titanium oxide nanoparticles with XAg = 0 (HAp/TiO2), 0.1, 0.25 and 0.5 (Ag:HAp/TiO2-NCS) was performed. The developed crystalline phase was characterized via X-ray diffraction (XRD), and the morphological features were executed via scanning and transmission electron microscopy (SEM/TEM). The HAp/TiO2 and silver doped HAp/TiO2 nanocomposites were spherical grains, with needle and flower-like structures. XRD examination revealed the crystalline phases of HAp/TiO2 and Ag-doped HAp/TiO2 nanocomposites. The crystallite size of HAp/TiO2 and Ag-doped HAp/TiO2 nanocomposites determined from the XRD pattern was ranged between 16 nm and 20 nm. The FTIR analysis confirms the presence of stretching and vibrational peaks for the presence of silver doped HAp/TiO2. The EDAX analysis showed the existence of major elements of HAp/TiO2 and Ag-HAp/TiO2 nanostructured composites. HAp/TiO2 and silver doped HAp/TiO2 were active against both Gram-positive and Gram-negative bacteria such as, E. coli (MTCC 443), S. typhi (MTCC 733), and S. aureus (MTCC 3160). The photocatalytic absorption spectrum implied an increased absorption rate of methylene blue by HAp/TiO2 and silver doped HAp/TiO2 nanocomposites. The photocatalytic activity revealed that 50% Ag doped HAp/TiO2 optimally improved photocatalytic activity.