Microstructure optimization of metal oxide nanoparticles and its antimicrobial activity

•Gamma radiation enhanced the optical properties of MgO-TiO2 nanoparticles.•Gamma radiation induced dielectric changes in the MgO-TiO2 nanoparticles.•Debye model determined the real and imaginary parts of nanoparticles.•XRD and SEM scans confirmed the crystalline nature of MgO-TiO2 nanoparticles.•MgO-TiO2 nanoparticles acquired a bactericidal activity. In this work, the impact of gamma irradiation on both optical and electrical characteristics of MgO-TiO2 oxide with different molar ratios of MgO has been studied. UV–VIS–NIR spectroscopy and Wimple-DiDomenico single-oscillator model was incorporated to investigate the dispersion parameters upon altering the MgO molar ratio and gamma irradiation (25–75 kGy). The induced changes in real and imaginary parts of the dielectric constant were determined using Debye dielectric relaxation process. Afterwards, the morphology of the nanoparticles was analyzed by SEM and XRD. Lastly, bactericidal activity of MgO-TiO2 was investigated against gram positive and negative bacteria. A significant decrease in the refractive index and dispersion energy was noted upon increasing the irradiation doses. The SEM revealed that gamma irradiation induced a slight decrease in the specific surface area of the nanoparticles with segregation in the crystals of TiO2 and MgO resulting in the formation of big agglomerate grains.