Microfluidic Development and Formulation of Medical and Industrial Nanoparticles

Metal nano-particles are in the middle of industrial and medical attention due to their unique and elevated physio-chemical and optical properties and wide application areas. The superior and radically improved properties is a function of size and shape of nanoparticles, which are determined by the fabrication process. Medical applications mostly require spherical nanoparticles for antimicrobial, and ligand or target analyte bio-conjugation. 

There are a number of techniques for fabrication of metal nanoparticles which are batch fabrication and a novel recent technique using microfluidics. The latter can be used to fabricate the nanoparticles at the point of use (POU) which eliminates the storage and anti-agglomeration problems. Moreover, the technique is scalable portable and agile and the process time from loading the chip to metal nanoparticle production in its final liquid suspended state takes less than 2 minutes.

To fabricate spherical particles we have used chemical reduction in a microfluidic reactor. This chemical process is a straight forward one-step process and can be implemented in a variety of setting in ambient or cooled environments. On the other hand, using micro-reactors enables better mixing, reduced size, seamless and spontaneous reaction from the material supply unit to the point of use. Sodium borohydride and silver nitrite was entered into the microreactor in ambient temperature in concentration ratios of 9/1. The product was colloidal silver nanoparticles at 43 nm and appropriate size monodispersity. Fundamental hydrodynamic and kinetic parameters which impact the size, its monodispersity and the reaction yield is studied via numerical simulations and experimental verifications. Characterizations were conducted by SEM and DLS to confirm the size, distribution and shape of the nanoparticles. 

The PDMS microreactor on chip were fabricated by soft lithography on glass. Different size of nanoparticles with appropriate/tunable monodispersity were successfully fabricated from 23nm to 43nm, by fine tunning the aforementioned hydrodynamic and reaction kinetic parameters. SEM images revealed that the particles are spherical in shape and were not agglomerated during the process. 

For more info please contact the Lab PI., the researcher on the project was Mr. Rostami