Antimicrobial activity of composite nanoparticles consisting of titania photocatalytic shell and nickel ferrite magnetic core

Reverse micelle and hydrolysis have been combined to synthesize composite nanoparticles consisting of anatase-titania photocatalytic shell and nickel ferrite magnetic core. The average particle size of the composite nanoparticles was in the range of 10-15 nm. The photocatalytic shell of titania is responsible for the photocatalytic and anti-microbial activity and nickel ferrite magnetic core is responsible for the mapetic behavior, studied by superconducting quantum interference device. The anatase TiO2 coated NiFe2O4 nanoparticles retains the magnetic characteristics of uncoated nanocrystalline nickel ferrites, superparamagnetism (absence of hysteresis, remarience and coercivity at 300 K) and non-saturation of magnetic moments at high field. The magnetic measurements results encourage their application as removable anti-microbial photocatalysts. Bacterial inactivation with UV light in the presence of titania-coated NiFe2O4 nanoparticles is faster than the action with UV light alone. (c) 2006 Elsevier B.V. All rights reserved.