Stabilization and enhanced anticancer activity of zinc oxide nanoparticles functionalized with chitosan and terephthalic acid

This study aimed to synthesize and evaluate zinc oxide (ZnO) nanoparticles functionalized with chitosan (ZnO CS) and chitosan-terephthalic acid (ZnO CS-TPA) for enhanced stability and biological activity in cancer therapy applications. The nanoparticles were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), Dynamic Light Scattering (DLS), and Zeta Potential measurements. XRD analysis revealed crystallite sizes of 244.75 Å for ZnO CS and 169.95 Å for ZnO CS-TPA, with microstrain values of 1.28 × 10⁻⁵ and 4.20 × 10⁻⁵, respectively. FESEM images showed distinct morphologies, with ZnO CS forming rod-like structures (lengths of 500–2000 nm) and ZnO CS-TPA exhibiting spherical particles ( <100 nm). DLS analysis indicated bimodal size distributions, with Z-average hydrodynamic diameters of 990.2 nm (ZnO CS) and 611.1 nm (ZnO CS-TPA), and polydispersity indices of 0.768 and 0.474, respectively. Zeta potential values were −52.8 mV for ZnO CS and −47.3 mV for ZnO CS-TPA, indicating good colloidal stability. Cytotoxicity studies against colon cancer cells (HT-29) using the MTT assay demonstrated significant dose-dependent activity, with ZnO CS-TPA showing enhanced efficacy compared to ZnO CS (viability reduction of ~70% vs. ~50% at 64 µg/mL). These findings suggest that surface modification of ZnO nanoparticles with chitosan and terephthalic acid enhances their stability and efficacy as potential agents for targeted cancer therapy.

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