The Electrostatic‐Mediated Formation of a Coordination Complex: the Trapping and Release of an Antitumor Drug with an Anthracycline Core from {Mo₇₂Fe₃₀}‐Based Ensembles

Abstract

This article studies the binding of the antitumor drug doxorubicin (DOX) with the nanocluster polyoxometalate (POM) {Mo 72 Fe 30 }, the latter serving as the drug carrier. The formation of a stoichiometric complex POM@(DOX) 12 was observed in aqueous media. Using the Stern-Volmer technique, we found the binding constant and free Gibbs energy for this interaction. The produced complex POM@(DOX) 12 was examined with ultraviolet-visible (UV-Vis), fluorescence (steady state and life-time), infrared (IR) and X-ray photoelectron spectro-scopy (XPS), which revealed the stoichiometry of complex and a key role of {Mo 3 Fe 3 } host pores on the POM surface to DOX binding. DOX's ability to intercalate into DNA after binding with the {Mo 72 Fe 30 } was investigated using a pH typical for blood (7.4). A pH-dependent release of DOX from POM@-(DOX) 12 was demonstrated (rate constant is 3.3 × 10 À 4 s À 1 ). Finally, we showed that the immobilization of doxorubicin on the POM's surface can reduce undesired side effects.

A polyacrylamide–chitosan semi-interpenetrating self-healing network with embedded Keplerate {Mo132} for pH-controlled release of Eu-fluorescent tags

“…12 Our previous results demonstrate that the template effect of the {Mo 132 }, as well as another giant POM with a toroidal structure -{Mo 138 }, governs the H to J-aggregates switching within the adsorption layer of cationic xanthene dyes on the POM's surface. 7 Other studies focused on how certain bioactive molecules, such as vitamin 13 B1, antitumor drug doxorubicine, 14 and tetracycline, 15 can be used to modify the analogous Keplerate {Mo 72 Fe 30 } structure through electrostatic interactions. Both Keplerate structures -{Mo 132 } and {Mo 72 Fe 30 } -demonstrated remarkable biocompatibility, 16 with {Mo 132 } being slightly more toxic for warm-blooded animals between the two POMs, making them promising templates for developing new functional hydrogel formulations.…”