Synthesis, characterisation and evaluation of polyethylene glycol-β-cyclodextrin-curcumin-zinc oxide nanoparticles...

To synthesise and characterise polyethylene glycol-β-cyclodextrin-curcumin-zinc oxide nanoparticles (PEG-Beta-Cur-ZnO NPs) and evaluate their stability, anti-mosquitocidal, antibacterial, and anticancer activities for potential biomedical and vector-control applications. Characterisation was performed using UV-Vis spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Transmission Electron Microscopy (TEM). Stability was assessed over time and pH ranges. Biological activity was evaluated through anti-malarial larval toxicity assays, adult mosquito longevity and fecundity studies, antibacterial assays against Escherichia coli and Staphylococcus aureus, and anticancer tests on HeLa cells measuring ROS generation, cell viability, DNA damage, and mitochondrial membrane potential. UV-Vis spectra confirmed successful functionalization with peak shifts to 423 nm. Stability studies showed time-limited dispersion (up to ~ 90 min) but improved stability under acidic conditions. FTIR revealed characteristic O-H, C=O, and Zn-O bands, confirming conjugation. XRD analysis indicated a preserved hexagonal wurtzite structure with high crystallinity. TEM imaging showed quasi-spherical morphology (76 nm). In larval assays, PEG-Beta-Cur-ZnO NPs achieved near-complete mortality at lower doses compared to free curcumin, while adult mosquitoes exhibited reduced lifespan and fecundity. Histopathology confirmed severe midgut damage in treated larvae. Antibacterial testing demonstrated superior inhibition zones and elevated ROS generation with PEG-Beta-Cur-ZnO NPs, indicating enhanced bacterial killing. In HeLa cells, the formulation induced significant ROS production, increased cell death, DNA fragmentation, and mitochondrial dysfunction compared to curcumin and ZnO NPs alone. PEG-Beta-Cur-ZnO NPs exhibit effective surface functionalization, pH-sensitive stability, and significantly enhanced larvicidal, antibacterial, and anticancer activities. These multifunctional nanoparticles show strong potential for eco-friendly vector control and biomedical applications.