General method for producing organic nanoparticles using nanoporous membranes.

Two liquids are separated by a nanoporous membrane and one liquid is made to flow into the other, causing nanoparticles to be formed at the exits of the nanopores. In particular, we report the generation of nanoparticles of the biodegradable polysaccharide polymer chitosan by placing the chitosan in a low pH aqueous solution that is flowed into a high pH aqueous solution. The size of the nanoparticles (5-20 nm) can be roughly controlled by choosing the size of the nanopores and the pumping rate. In addition, it is possible to load the chitosan nanoparticles with drug molecules, which is demonstrated by incorporation of up to 3.3% rhodamine 6G molecules in the chitosan nanoparticles.