Binding of a Fatty Acid-Functionalized Anderson-Type Polyoxometalate to Human Serum Albumin

[Image: see text] The Anderson-type hexamolybdoaluminate functionalized with lauric acid (LA), (TBA)(3)[Al(OH)(3)Mo(6)O(18){(OCH(2))(3)CNHCOC(11)H(23)}]·9H(2)O (TBA-AlMo(6)-LA, where TBA = tetrabutylammonium), was prepared via two synthetic routes and characterized by thermogravimetric and elemental analyses, mass spectrometry, IR and (1)H NMR spectroscopy, and powder and single-crystal X-ray diffraction. The interaction of TBA-AlMo(6)-LA with human serum albumin (HSA) was investigated via fluorescence and circular dichroism spectroscopy. The results revealed that TBA-AlMo(6)-LA binds strongly to HSA (63% quenching at an HSA/TBA-AlMo(6)-LA ratio of 1:1), exhibiting static quenching. In contrast to TBA-AlMo(6)-LA, the nonfunctionalized polyoxometalate, Na(3)(H(2)O)(6)[Al(OH)(6)Mo(6)O(18)]·2H(2)O (AlMo(6)), showed weak binding toward HSA (22% quenching at a HSA/AlMo(6) ratio of 1:25). HSA binding was confirmed by X-ray structure analysis of the HSA-Myr-AlMo(6)-LA complex (Myr = myristate). These results provide a promising lead for the design of novel polyoxometalate-based hybrids that are able to exploit HSA as a delivery vehicle to improve their pharmacokinetics and bioactivity.