At higher TFR values a broadening of size distributions was noted via DLS (polydispersity indices > 0.2) along with the co-existence of sub 60 nm particles (possibly liposomes), thought to arise from turbulence in the F-127/buffer stream with increased back pressure (see supplementary information SI Fig. ). Each FRR value was tested in triplicate, using three separately prepared solutions (polymer and lipid) on three different PDMS chips to best account for any batch-to-batch variation. As shown in Fig. A, an inverse relationship between FRR and particle size (analysed by DLS) was seen for each composition used. Particles between 180 nm and 300 nm were generated (dependant on FRR), with polydispersity indices (PDI) below 0.2 (shown in Fig. ). No change in size was observed between particles analysed immediately after collection and samples where residual ethanol was removed under a nitrogen stream, suggesting the presence of ethanol had a negligible effect on particle stability. Many drug-delivery and nanoengineering applications require precise control over particle size distribution, rendering this a significant result.