Hydroxyapatite/zinc oxide functionalized with folic acid as a curcumin carrier for cancer treatment

ABSTRACT The primary treatment for cancer is chemotherapy; however, it causes side effects, which motivates research focused on the development of delivery systems for antineoplastic agents. One example is the hydroxyapatite (HAp) carrier, as it is a biocompatible and non-toxic biomaterial that can acquire antibacterial properties with the addition of zinc oxide (ZnO) nanoparticles, preventing possible infections during surgical procedures. Furthermore, functionalization with folic acid (FA) enables active targeting of tumor cells, while curcumin (Cur) exhibits antitumor activity. The objective of this study was to develop a carrier with antibacterial properties using FA-functionalized HAp@ZnO for curcumin delivery. HAp synthesized by the hydrothermal method was evaluated through in vitro bioactivity assays. Subsequently, ZnO nanoparticles were incorporated into HAp, and antibacterial activity was assessed against Staphylococcus aureus and Escherichia coli. The material was then functionalized with FA, curcumin was incorporated, and hemolysis and cytotoxicity assays were performed. Characterization techniques included Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Brunauer–Emmett–Teller (BET) surface area analysis, and Ultraviolet–Visible (UV–Vis) absorption spectroscopy. The synthesized HAp exhibited a crystalline, bioactive material with high surface area. HAp@ZnO showed well-defined inhibition halos for both bacteria, except for the HAp@20%ZnO sample against E. coli. The amount of curcumin adsorbed was 54.79 ± 3.52% for HAp@10%ZnO.AF.Cur and 45.49 ± 3.79% for HAp@20%ZnO.AF.Cur. HAp effectively modulated the toxicity of the active components, significantly reducing the hemolytic effects of ZnO and curcumin. The results indicate biocompatibility in non-tumor cells and suggested differential cytotoxic response in tumor cells. Therefore, a promising carrier for targeted antitumor therapy was developed, combining antibacterial activity, active targeting, controlled release, and biocompatibility.