Emulsion-Solvent diffusion in a double-chip microfluidic platform for scalable production of Lipid@PLGA nanoparticles delivering siRNA therapeutics

Scalable nanoparticle manufacturing remains a key bottleneck in the clinical translation of RNA-based nanomedicines. In this study, we demonstrate the successful adaptation of a conventional emulsion-solvent diffusion protocol into an automated microfluidic workflow, illustrating its potential for streamlined and scalable nanoparticle production. Using the Sunshine™ microfluidic platform (Unchained Labs), we systematically optimized formulation and process parameters to produce siRNA-loaded hybrid lipid-polymer nanoparticles, featuring a poly(lactic-co-glycolic acid) (PLGA) core and a dipalmitoylphosphatidylcholine shell (mDPPC@PLGA hNPs). Optimised mDPPC@PLGA hNPs exhibited key technological features, matching or exceeding the quality of their benchtop equivalents (bDPPC@PLGA hNPs). Using poly(vinyl alcohol) (PVA) as a stabilizer, monodisperse mDPPC@PLGA hNPs with controlled size (<170 nm) and consistent zeta potential (-30 mV) were achieved with production yields ≥ 40 %. The ability of mDPPC@PLGA hNPs to effectively entrap and slowly release a siRNA targeting nuclear factor NF-κB (siNFκB) was successfully demonstrated. Structural characterization through thermodynamic and SAXS analyses confirmed that the microfluidic produced hNPs retained comparable internal architecture to their benchtop counterparts. Most notably, siNFκB-loaded mDPPC@PLGA hNPs resulted in effective in vitro downregulation of NFκB in lipopolysaccharide-stimulated A549 lung epithelial cells. Collectively, these results establish a novel and robust approach for the scalable fabrication of functional, siRNA-loaded hybrid nanoparticles via emulsion-solvent diffusion, leveraging a commercially available, automated microfluidic system with a serial chip configuration.