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.
1. M. T. Pope, “Polyoxoanions: synthesis and structure” in Comprehensive Coordination Chemistry II: Transition Metal Groups, A. G. Wedd, Ed., 2004, 4, 635, Elsevier Science, New York, NY, USA.
2. X. López, J. J. Carbó, C. Bo and J. M. Poblet, Chem. Soc. Rev. 2012, 41, 7537
3. a) B. Keita, T. B. Liu and L. Nadjo, J. Mater. Chem., 2009, 19, 19; b) S. G. Mitchell and J. M. de la Fuente, J. Mater. Chem., 2012, 22, 18091; c) Y. F. Wang and I. A. Weinstock, Chem. Soc. Rev., 2012, 41, 7479; d) F. F. Bamoharram, A. Ahmadpour, M. M. Heravi, A. Ayati, H. Rashidi and B. Tanhaei, Synth. React. Inorg. Met.-Org. Chem., 2012, 42, 209.
4. I. V. Kozhevnikov, Chem. Rev., 1998, 98, 171.
5. T. Yamase, J. Mater. Chem., 2005, 15, 4773.
6. L. De Matteis, S. G. Mitchell* and J. M. de la Fuente, J. Mater. Chem. B, 2014, 2, 7114.
7. I. Maicas Gabas, G. Stepien, M. Moros, S. G. Mitchell* and J. M. de la Fuente, New J. Chem., 2016, 40, 1039.