Functionalised solids delivering bioactive nitric oxide gas for therapeutic applications

It is well established that nitric oxide is an effective vasodilative, antibacterial and tumoricidal agent, however its targeted delivery in a controllable manner is challenging but necessary for successful therapeutic applications. In recent years a few new methods have been developed, based on the formation of N-diazeniumdiolates, S-nitrosothiols and metal NO coordination bonds in material structures. The typical delivery materials include nanoporous materials (such as zeolites and metal organic frameworks), silicate particles and polymers containing amine and thiol functional groups. These materials are of promising potential for delivering controllable doses of bioactive NO gas to meet the unmet therapeutic needs in the future. This review summarises these delivery materials and relevant biological assessments. Further improvement of current methods and new design of NO donors are still required in order to address the issues on NO storage and its release profile in matching with the clinical requirements