Rosmarinic acid-loaded folic acid-chitosan nanoparticles: Synthesis, characterization, and anticancer effects on liver cancer cell line HepG2

This study investigates the synthesis and comprehensive characterization of folic acid–chitosan (FA–CS) nanoparticles encapsulating rosmarinic acid (RA), with the aim of evaluating their suitability as a targeted drug delivery system for liver cancer therapy. The nanoparticles were prepared using the ionic gelation method, yielding formulations with different RA loading concentrations. The nanoparticles were analyzed for size and surface charge using dynamic light scattering (DLS), for morphology and shape through scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and for chemical conjugation by Fourier transform infrared spectroscopy (FTIR), which revealed the functional groups and verified their composition. The optimized nanoparticles displayed a mean particle diameter of approximately 150 nm with a relatively narrow distribution profile. The zeta potential values ranged between + 8 to + 9 mV, suggesting satisfactory colloidal stability with minimal aggregation tendency. The encapsulation efficiency was approximately 65%, indicating successful incorporation of rosmarinic acid within the polymeric nanoparticle system. FTIR spectra confirmed the successful encapsulation of RA within the nanoparticulate matrix, indicating efficient drug loading. The successful conjugation of folic acid (FA) to chitosan (CS) was confirmed by ¹H NMR spectroscopy, where the appearance of a characteristic amide proton signal indicated amide bond formation between FA and CS. SEM analysis demonstrated that the nanoparticles were spherical with smooth surface morphology, while TEM imaging further verified the incorporation of rosmarinic acid within the chitosan–folic acid conjugated framework. The anticancer efficacy of the RA-loaded FA–CS conjugate was evaluated using the MTT assay in HepG2 liver cancer cells, where they exhibited significant cytotoxic activity.