(A, B) Effect of mixing kinetics profile (τM and flow rate Q) on the average nanoparticle size Dz (A) and uniformity shown as the DLS size standard deviation (B). The mixing kinetics scale is divided into two regions: Region I (τM < τA) and Region II (τM > τA). Labels 1, 2 and 3 denote three representative preparations generated from three different mixing conditions; (C) Transmission electron microscopy (TEM) images and DLS profiles of the three sets of nanoparticles prepared at Q = 1.25 mL/min, τM = 1.8 × 105 ms (Prep. 1), Q = 5 mL/min, τM = 790 ms (Prep. 2), and Q = 20 mL/min, τM = 15 ms (Prep. 3). Scale bar = 50 nm (for left panel) and 200 nm (for right panel); (D, E) Effect of input pDNA concentration and plasmid size on the average nanoparticle size Dz (D) and zeta potential (E) prepared by τM = 15 ms; (F, G) Effect of N/P ratio on the average nanoparticle size Dz (F) and zeta potential (G) prepared by τM = 15 ms. For the conditions tested, the size profile and zeta potential of pDNA/lPEI nanoparticles did not vary with the N/P ratio from 4 to 6.