Metal-organic polyhedra as intracellular nitric oxide delivery systems towards biomedical applications

Nitric Oxide (NO) is a molecule with wide-ranging therapeutic potential but is challenging to administer due to its reactive nature. Drug delivery systems (DDS) that can deliver NO reliably and efficiently allow for its exogenous administration with spatiotemporal control of the release. This study introduces two water-soluble metal-organic polyhedra (MOPs) based on dirhodium or diruthenium paddlewheels assembled in a cuboctahedral geometry, decorated with sulfonate groups on their surface. NO molecules coordinate with the open-metal sites (OMS) at the axial site of the paddlewheel moieties. We studied NO capture and release in the solid state and in physiological media in response to two stimuli: light and water. The release amount and its kinetics were varied by changing the light intensity and duration. We further investigated the spatiotemporal control of the NO release in a single cell, establishing the potential of these molecules for biomedical applications.