Maghemite–gold core–shell nanostructures (γ-Fe2O3@Au) surface-functionalized with aluminium phthalocyanine for multi-task imaging and therapy

Abstract

In this study we report on the elaboration and characterization of core–shell maghemite–gold nanoparticles with the shell modulated for different thicknesses below 2 nm. Gold-shelled maghemite nanoparticles with an average core size of about 9 nm were developed using a single-step protocol involving reduction of Au³⁺ in the presence of citrate-coated maghemite nanoparticles. Additionally, post-functionalization of the core–shell structures with aluminium phthalocyanine was successfully accomplished, aimed at the production of a material platform for photodynamic therapy. The as-produced samples were structurally, morphologically, magnetically and optically characterized and presented long-term colloidal stability at physiological pH. Impressively, we found the as-produced samples showed good X-ray attenuation properties, making them able to be used as nanoprobes for targeted computed tomography. Moreover, in vitro nanocytotoxicity tests confirmed a superior biocompatibility of the as-produced samples, making them a very promising multi-task platform for in vivo applications.