A non-viral and efficient carrier for the applications delivering drugs, plasmic DNA, shRNA for pharmaceutical and therapeutic applications is presented. The cationic lipid based liposomal carriers which has been the most attractive non-viral solution. The size of complexes of cationic lipid and DNA (lipoplex) dictates the efficiency of gene transfection. Moreover, the order of mixing of cationic lipid and DNA, mixing rate, and mixture incubation time are factors that determine the lipoplex sizes during sample preparation. We developed a Picoliter Micro Reactor and Incubator (PMRI) system to formulate monodisperse cationic lipids and DNA complexes. The monodisperse micro reactor and incubator was designed and fabricated based on the microfluidic droplet formation devices which developed by our lab and others. Compared with the conventional irreproducible lipoplex preparation using hand-shaking or vortexing processes for mixing, the PMRI system we developed for lipoplex formulation demonstrates the ability of rapid and uniformly mix cationic lipid and DNA simultaneously, and generates a narrower size distribution peak and smaller average size. The PMRI also enables the mixing and incubation integrated process and lipolex formulation reproducibility.