Synthesis of gold nanoparticles using a vortex-type micro-mixing system

A new microfluidic reaction chip capable of mixing, transporting and reacting is developed for synthesis of gold nanoparticles with tunable sizes. It allows for a rapid and a costeffective approach to accelerate the synthesis of gold nanoparticles. The microfluidic reaction chip was made of CNC machining and PDMS casting process to integrate a vortex-type micro-mixer and a micro-pump on a single chip. The micromixer is capable of generating a vortex-type flow field to achieve a mixing efficiency as high as 94% within 1 second. Successful synthesis of dispersed gold nanoparticles has been demonstrated within a shorter period of time (5 minutes), as compared to traditional methods. The dispersed gold nanoparticles had an average diameter of 17 nm, 23 nm and 48 nm, respectively. The size of the nanoparticles can be fine-tuned by using reagents with different volumes. The development of the microfluidic reaction system is promising for synthesis of functional nanoparticles for further biomedical applications.