B-066 Development and Characterization of mPEG-Chitosan Nanoparticles for the Co-delivery of Curcumin and KRAS-targeting siRNA in Lung Cancer Models

Abstract

Lung cancer represents one of the most lethal malignancies worldwide, exhibiting both high incidence and mortality rates. It remains the primary cause of cancer-related deaths among men and women. Several factors contribute to its lethality including late diagnosis and the limited effectiveness of current treatments. KRAS mutations are present in approximately 30% of lung cancers and continue to pose significant clinical challenges. Conventional delivery methods for RNA interference and lipophilic polyphenols, such as curcumin, are hindered by poor stability and low bioavailability. This study seeks to develop and analytically characterize a novel platform based on mPEG-Chitosan nanoparticles for the co-delivery of KRAS-targeting siRNA and curcumin, aiming to enhance therapeutic efficacy in A549 lung cancer cells. Bare mPEG chitosan nanoparticles and nanoparticles loaded with drug agents were formed by the ionic gelation method using sodium tripolyphosphate (TPP) at optimum pH conditions. Physicochemical properties, including hydrodynamic diameter, polydispersity index (PDI), were measured using Dynamic Light Scattering (DLS). Zeta potential and sample colloidal stability against aggregation were also assessed. Surface morphology was characterized by Scanning Electron Microscopy (SEM). Encapsulation efficiency for curcumin and siRNA was quantified using UV-Vis spectrophotometry at 425 nm for curcumin and fluorescence spectroscopy with SYBR Tm gold for siRNA. In vitro release kinetics of the nanoparticles were evaluated over 24 hours to assess the delivery profile. Dynamic light scattering (DLS) analysis confirmed the formation of nanoparticles, with bare nanoparticles exhibiting a hydrodynamic diameter of 220 nm, which increased to 265 nm following dual-loading with curcumin and siRNA. SEM micrographs showed well-defined, spherical nanoparticles with smooth surfaces. Zeta potential measurements indicated near-neutral surface charges for both bare (+1.37 ± 0.52 mV) and dual-loaded (+2.71 ± 0.48 mV) formulations, suggesting effective surface shielding by the mPEG chains. UV-Vis spectrophotometry of the dual-loaded system showed distinct absorption peaks at 260 nm for siRNA and 425 nm for curcumin, confirming successful co-encapsulation. Release studies in phosphate buffer demonstrated controlled-release profiles for the nanoparticles, with 80% release at 20 hours, compared to the relatively rapid burst release of free curcumin, which reached approximately 90% within 2 hours. This biphasic, sustained release behavior suggests effective drug entrapment within the nanoparticle core and a diffusion-regulated release mechanism. The results show the successful development of a stable mPEG-Chitosan nanoparticle system, which can deliver both lipophilic drugs and nucleic acid material at the same time. The near-neutral zeta potential is consistent with an effective mPEG surface coating and is commonly associated with reduced nonspecific interactions, potentially leading to decreased immune recognition and clearance. Instead of a quick burst release, curcumin was released steadily over a longer period of 20 hours, showing that the system can protect its payload and extend the time during which the drugs are active. This dual-loaded system provides a strong foundation for future work targeting KRAS gene silencing and combined cancer treatments in KRAS-mutant models.