Controlled drug delivery from chitosan-coated heparin-loaded nanopores anodically grown on nitinol shape-memory alloy

The study aims to enable local, controlled delivery of the cardiovascular drug heparin using nitinol (a shape-memory alloy) as the base material. The nitinol is treated by electrochemical anodizing to create a regular nanoporous Ni-Ti-O layer, and then coated with chitosan. Researchers analyze how the surface structure and wettability change after anodizing, including reduced water contact angle (increased hydrophilicity). They also measure heparin release behavior and fit the release kinetics using multiple models (Higuchi, first-order, zero-order, and Korsmeyer–Peppas), concluding that chitosan mainly controls release through a diffusional mechanism. In vitro cell tests using HUVEC viability indicate the samples are non-cytotoxic, with the best performance reported for the chitosan-coated specimens. The authors conclude the system is promising for cardiovascular drug delivery, particularly for stent applications.