319: Engineered ionizable lipid nanoparticles for red blood cell targeting and drug delivery

Abstract: Ionizable lipids are the molecular engine of lipid nanoparticle (LNP) delivery systems. Their pH-responsive behavior enables efficient electrostatic complexation with nucleic acids during formulation while remaining neutral at physiological pH to reduce systemic toxicity. Upon endosomal acidification, protonation of ionizable lipids promotes membrane destabilization and cytosolic payload release, overcoming the primary intracellular barrier to gene delivery. We hypothesize that specifically engineered ionizable lipid nanoparticles (LNPs) can fuse directly with the RBC membrane under mild acidic conditions (e.g., pH 6.5), allowing for direct cytoplasmic delivery of molecules. In this work LNPs were synthesized by various methods and components were associated in terms of size (50-200nm), polydispersity index (PDI), morphology, and electrophoretic potential measurements (-10 to -50 mV). In particular, three methods, namely thin film hydration, microfluidic systems with an air compressor, and microfluidic systems with a peristaltic pump were used. LNPs with and without ionizable lipids and with and without an ionic liquid coating were produced. The size and the PDI of the LNPs were characterized by dynamic light scattering (DLS) in hydrated state. Electron microscopy was used to examine the anhydrous state morphology of the LNPs while a zeta potential analyzer was utilized to effectively measure the surface charge. Efficient delivery of therapeutics to RBCs remains a major challenge due to their enucleated structure and unique membrane biology. Here, we developed ionizable lipid-based lipid nanoparticles engineered for targeted delivery to RBCs. By tuning lipid composition and ionization behavior, the platform enabled controlled encapsulation and membrane interaction while maintaining RBC integrity. These LNPs demonstrate efficient payload association with minimal hemolysis and preserved cellular function. The particles carried nanobody for targeting glycophorin A receptors on the surface of RBCs. This strategy establishes a scalable nanotechnology platform for RBC-directed drug delivery with potential applications in transfusion medicine and hematologic disorders. Complete biophysical characterization, drug loading efficiency and cellular interactions studies will be discussed in the presentation.