Herringbone-Patterned 3D-Printed Devices as Alternatives to Microfluidics for Reproducible Production of Lipid Polymer Hybrid Nanoparticles.

Major barriers to the implementation of nanotechnology include reproducible synthesis and scalability. Batch solution phase methods do not appear to have the potential to overcome these barriers. Microfluidic methods have been investigated as a means to enable controllable and reproducible synthesis; however, the most popular constituent of microfluidics, polydimethylsiloxane, is ill-suited for mass production. Multi-inlet vortex mixers (MIVMs) have been proposed as a method for scalable nanoparticle production; however, the control and reproducibility of the nanoparticle is wanting. Here, we investigate the ability to improve the control and reproducibility of nanoparticles produced by using 3D printed MIVMs with herringbone patterns in the flow channels. We compare three methods, viz., microfluidic, MIVM, and herringbone-patterned MIVM methods, for the synthesis of lipid-polymer hybrid nanoparticles (LPHNPs). The 3D printed herringbone-patterned MIVM method resulted in the smallest LPHNPs with the most uniform size distribution and shows more reproducible results as compared to the other two methods. To elucidate the mechanism underlying these results, concentration slices and vorticity streamlines of mixing chambers have been analyzed for 3D printed herringbone-patterned MIVM devices. The results bode well for LPHNPs, a formulation widely investigated for its improved therapeutic efficacy and biocompatibility. The herringbone-patterned device also has the potential to be broadly applied to many solution phase processes that take advantage of efficient mixing. The methods discussed here have broad implications for reproducible production of nanoparticles with constituents such as siRNA, proteins, quantum dots, and inorganic materials.