Strategies in Microfluidic Self-Assembled Nanoparticles

The current work presents the using of microfluidic hydrodynamic flow focusing for enabling an accurate control of self-assembling nanoparticles. A mixture of surfactant and DNA dispersed in 35% ethanol is focused between two streams of pure water in a microfluidic channel. As a result, a rapid change of solvent quality takes place in the central stream, and the surfactant-bound DNA molecules undergo a fast coil-globule transition. Using this method nanoparticles having a hydrodynamic diameter of 70nm with a polydispersity index below 0.2 were achieved. A second method relied on the controlled diffusive mixing of surfactant and DNA solutions through a water stream of tunable width. Using this method the smallest nanoparticles achieved were about 30 nm in hydrodynamic diameter, meaning that most of them contained a single DNA molecule.