Novel metal-organic framework coated with chitosan-κ-carrageenan as a platform for curcumin delivery to cancer cells

Metal-organic frameworks (MOFs) have shown great promise as pH-responsive drug delivery systems, with considerable potential for targeted cancer therapy. In this study, we synthesized a novel curcumin-loaded MOF, named UWO-2 (CUR@UWO-2), and developed its biocomposite form, CS-kappa-Cr/CUR@UWO-2, by coating it with chitosan (CS) and kappa-carrageenan (kappa-Cr). Structural analysis through powder X-ray diffraction (PXRD) confirmed the successful synthesis of UWO-2 and the incorporation of CUR within the MOF structure. X-ray photoelectron spectroscopy (XPS) analysis revealed two distinct peaks at approximately 1021.15 eV and 1044.23 eV, corresponding to the Zn 2p3/2and Zn 2p1/2states, respectively. These peaks confirm the presence of the expected Zn2+ oxidation state in UWO-2, further validating its successful synthesis. Brunauer-Emmett-Teller (BET) analysis demonstrated a significant decrease in surface area (367.4 m2/g) and pore volume (0.296 cm3/g), validating the entrapment of CUR within the UWO-2 MOF structure. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images revealed that UWO-2 particles are spherical with a smooth surface, while CUR@UWO-2 exhibited a larger particle size, indicating successful curcumin loading. Thermogravimetric analysis (TGA) indicated enhanced thermal stability due to CUR loading, while swelling experiments revealed increased water absorption at neutral pH, supporting effective drug release under physiological conditions. Biodegradation studies showed sustained degradation of CUR@UWO-2 in the presence of lysozyme, confirming its suitability for in-vivo applications. The drug delivery system achieved 21.9 % drug loading and 75.1 % encapsulation efficiency. Drug release experiments indicated accelerated release under acidic conditions, with the Korsmeyer-Peppas model identifying Fickian diffusion as the primary release mechanism. Cytotoxicity assessments showed increased cell death with CUR@UWO-2, enhanced by the synergistic effect of UWO-2, while the CS-kappa-Cr coating enabled controlled, prolonged curcumin release. Confocal microscopy confirmed cellular uptake of CUR, underscoring the potential of the biocomposite for tumor-targeted chemotherapy applications in cancer treatment. This study highlights the potential of CUR@UWO-2, especially in its biocomposite form, for tumor-targeted drug delivery applications.