Curcumin-loaded chitosan/polyethyleneimine nanogels promoting antibacterial and antioxidant activity

Curcumin (CUR) exhibits pleiotropic effects beneficial for preventing or treating chronic diseases. To enhance its stability, bioavailability, and controlled release, while mitigating limitations from high-dose or long-term exposure, we synthesized innovative biocompatible chitosan/polyethyleneimine nanogels (Ngs) to encapsulate CUR (CUR-Ngs). Fourier-transform infrared spectroscopy (FTIR) confirmed spectral compatibility. Electron microscopy revealed a spherical morphology, with average diameters of 69.78 ± 5.1 nm (empty Ngs) and 115.71 ± 6.02 nm (CUR-Ngs). The CUR-Ngs demonstrated a loading capacity (LC) of 9.4 ± 0.36 % and an encapsulation efficiency (EE) of 68.1 ± 2.4 %. CUR release from the Ngs exhibited a triphasic profile: an initial burst (25 %) within 3 h, followed by a gradual release culminating in a total sustained liberation of 67.7 % by 96 h. On both HUVEC and HGF cell lines, CUR-Ngs and empty Ngs demonstrated significantly higher relative cell viability (RCV, %) than free CUR at all tested concentrations (P < 0.001). Furthermore, lactate dehydrogenase (LDH), reactive oxygen species (ROS), and lipid peroxidation (LPO) assays indicated that CUR-Ngs significantly mitigated oxidative stress in HUVEC cells. The CUR-Ngs also demonstrated potent antibacterial activity, with minimum inhibitory concentration (MIC) values determined against Staphylococcus aureus, Enterococcus faecalis, methicillin-resistant S. aureus (MRSA), and vancomycin-resistant Enterococcus (VRE). These findings highlight the potential of CUR-Ngs as a potent agent against critical antibiotic-resistant pathogens, such as MRSA and VRE, commonly associated with healthcare-associated infections (HCAIs).