Process Design for Small-Scale Production of PEGDA-NVP Hydrogel Nanoparticle Emulsions for Therapeutic Applications

Abstract

Hydrogel nanoparticle emulsions (HNEs) are promising platforms for intracellular therapeutic delivery, yet their synthesis at bench scale (267 mL) requires large quantities of material, which limits iterative optimization with high-value cargos. Here, we established a small-scale inverse phase (water-in-oil, W/O) miniemulsion polymerization (IPMP) process (15 mL) that reduced material requirements by >90% while maintaining key process design criteria. Using poly(ethylene glycol) diacrylate (PEGDA) and n-vinyl-2-pyrrolidinone (NVP), we demonstrate that the small-scale process maintains key measured formulation attributes, including nanoparticle tracking analysis (NTA)-derived particle diameter distributions, swelling ratios, swelling-derived mesh dimension estimations, and colloidal stability for at least three years. Process scale-down identified optimized parameters for homogenization, sonication, nitrogen purging, and reaction time and yielded nanoparticles with reproducible NTA-derived size metrics, concentration, and swelling-derived mesh dimension estimations. PEGDA-2000-based HNEs were cytocompatible according to International Organization for Standardization (ISO) 10993-5 exceeding the cytotoxic threshold (≥70% viability) under en masse administration. Fluorescently labeled HNE nanoparticles exhibited rapid internalization in adipocytes, which are typically resistant to transfection. With administration of HNEs loaded with green fluorescent protein (GFP) cargo, cells showed delayed appearance of GFP-associated fluorescence on day 8, consistent with time-dependent cargo release. Collectively, these findings establish a small-volume HNE synthesis platform that reduces material requirements while preserving evaluated formulation attributes across scales and demonstrating intracellular cargo delivery.