The size and redox properties of molecular polyoxometalates (POMs) make them extremely relevant for bioapplications: from disrupting tumour growth and enzyme inhibition, to DNA-intercalating agents and antimicrobial applications. POMs are oligomeric aggregates of metal cations (usually the d⁰ species V(V), Nb(V), Ta(V), Mo(VI), and W(VI)) bridged by oxide anions that form by self-assembly processes.¹ POMs are model electron-transfer catalysts due to their unique ability to reversibly donate and receive electrons without changing their structural conformation.² This property, coupled with their high anionic charge, makes them suitable for the preparation of zero-valent state metal nanoparticles (NPs) such as Pt, Pd, Ru, Au and Ag from molecular precursors.³ Although POMs are traditionally employed in catalysis,⁴ they have also been shown to be extremely efficient inorganic antiviral, antitumoural and antimicrobial agents.⁵ Polyoxometalate-stabilised nanoparticles (NPs@POM) are therefore an ideal delivery vehicle for bioactive POMs as novel inorganic antimicrobial⁶ and anticancer⁷ agents.

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