Synthesis of hollow, magnetic Fe/Ga-based oxide nanospheres using a bubble templating method in a microfluidic system

This paper describes a new approach to synthesize hollow nanospheres in a microfluidic system using air bubbles as templates. A new microfluidic system which integrates a micro-mixer, a micro-condenser channel, microvalves, a micro-heater, and a micro-temperature sensor, to form an automatic micro-reactor, is used to generate air bubbles that assist in the synthesis of hollow Fe/Ga-based oxide nanospheres. Experimental data show that Fe/Ga-based oxide nanoparticles with a diameter of 157 +/- A 26 nm can be successfully synthesized. The formation mechanism is that the seed nanoparticles are attaching themselves onto the bubbles to form a solid shell. The magnetic properties of the hollow Fe/Ga-based oxide nanospheres are also measured. This may be a promising platform to synthesize hollow nanoparticles for drug delivery applications.