• biodegradable nano-architectures
• contrast agents
• imaging
• metal nanoparticles
• micro-CT

Metal nanoparticles have demonstrate an enormous potential for biomedical applications. This is related to their peculiar chemical, physical and physiological behaviors. Moreover, the possibility to combine the nanoparticles with drugs and to modify their surface by targeting agents have paved the way to the named “personalized medicine”. Until now, various imaging modalities have been developed such as MRI, CT, PET, ultrasound and SERS, as an aid to image different disease states. These imaging methods differ in both techniques and instrumentation and more importantly require a contrast agent with unique physiochemical properties. This led to the invention of various nanoparticulated contrast agents such as gold nanoparticles for their application in these imaging modalities. On the other hand, their translation from the bench to the clinical trials is hampered from in vivo accumulation issues. Indeed, metal nanoparticles are not degradable and their final fate is usually the accumulation in liver and spleen, causing long term toxicity and interference with common medical diagnosis. In this contest, a novel family of inorganic metal nano-architectures able to jointly combine the most intriguing features of metal nanoparticles with their fast-degradation and potential renal clearance was introduced. In this work, the optimization of the synthetic protocol to produce suitable nano-architectures for CT imaging is presented and the sensitivity of a micro-CT scanner is evaluated for the new contrast agents. First, the nanostructures were fully characterized by standard techniques, among which UV-vis spectrophotometry, electronic microscopy (TEM-SEM) and ICP-MS. Furthermore, other synthesis and similar tests have been conducted on chelating agents. Finally, new-found nano-architecture imaging efficiency was evaluated by a micro-CT device and compared to standard nano-architecture, together with their degradation timescale. The development of this novel protocol strongly supports further insights on these innovative degradable nano-architectures suitable for imaging techniques that requires high concentration of noble metals.