Design of liquid crystalline nanoparticles: Linking composition to membrane interactions and siRNA delivery

Abstract

The clinical translation of small interfering RNA (siRNA) therapeutics critically depends on delivery systems capable of protecting nucleic acids, enabling efficient cellular uptake, and promoting cytosolic release. Liquid crystalline nanoparticles (LCNs) are promising carriers due to tunable internal nanostructure and biocompatibility, yet how composition controls membrane affinity and biological performance remains limited. Here, we compared two cationic reverse-hexagonal LCNs formulated from monoolein, oleic acid, poly(allylamine hydrochloride) and either poloxamer 407 (P407) or poloxamer 188 (P188). Both LCN-P407 and LCN-P188 shared reverse-hexagonal organization, mean diameters of 150–185 nm, low polydispersity (0.09–0.18), positive zeta potentials (10–20 mV), and protection of siRNA from RNase A. Langmuir isotherms and Brewster angle microscopy revealed pronounced adsorption and expansion of DPPC monolayers, with LCN-P188 inducing stronger perturbations, consistent with its higher cytotoxicity (∼20% increase in cell death) relative to LCN-P407. Crucially, siRNA delivered by LCN-P407 showed significantly greater uptake (> 1.7-fold) than that administered by LCN-P188. Functionally, as a proof of concept, we showed that LCN-P407-siTNFα induced robust gene silencing in LPS-stimulated macrophages, reducing TNFα secretion by 1.2–3.5-fold depending on particle concentration and incubation time. LCN-P188-siTNFα produced only delayed and modest reductions (1.3–1.6-fold). In addition, in dermatomized porcine skin, LCN-P407 also exhibited superior cutaneous penetration, delivering siRNA efficiently into the viable epidermis and dermis. Collectively, these results reveal a direct relationship between LCN composition, membrane affinity, and functional performance, providing mechanistic insight for the rational design of LCN-based carriers in RNA therapeutics.