Localized drug delivery of selenium (Se) using nanoporous anodic aluminium oxide for bone implants

Electrochemically engineered nanoporous anodized aluminium oxide (AAO) prepared on aluminium (Al) foil by anodization process was employed as a platform for loading different forms of selenium (Se) in order to investigate their release behaviour and potential application for localized drug delivery targeting bone cancer. Several forms of Se including inorganic Se (H₂SeO₃), organic Se ((C₆H₅)₂Se₂), metallic Se, their chitosan composites, electrodeposited (ED) and chemical vapour deposited (CVD) Se were explored and combined with another model drug (indomethacin). Structural, drug-loading and in vitro drug-releasing characteristics of prepared Se-based drug delivery carriers were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and UV-visible spectroscopy (UV-Vis), respectively. Sustained and controlled release of Se was demonstrated through chitosan-composites of inorganic, organic or metallic forms of Se loaded into nanoporous AAO carriers. Cell viability studies showed decreasing toxicity to cancer cells in the order: inorganic Se > ED Se > CVD Se > metallic Se > organic Se. The study suggests new alternatives for localized drug treatment based on low-cost nano-engineered carriers loaded with Se having anti-cancer properties.