Vanadium-Substituted Tungstosulfate Polyoxometalates As Peroxidase Mimetics And Their Potential Application In Biosensing

This article reports on the peroxidase-like catalytic activity of polyoxometalates (POMs) and their potential use as natural peroxidases for developing a simple and efficient colorimetric glucose sensor. Two Keggin-type vanadium-substituted tungstosulfates, [SVW11O40](3-)(SVW11) and [SV2W10O40](4-)(SV2W10), were tested for their potential as natural enzyme mimetics and exhibited strong peroxidase-like catalytic activity. The catalysis reaction was found to be in accordance with Michaelis-Menten and Lineweaver-Burk kinetics models. Michaelis-Menten constant (K-m) and maximum velocity (V-max) parameters were calculated to be 0.0759 mM and 0.329x10(-8)Ms(-1)for SVW11, and 0.0543 mM and 2.67x10(-8)Ms(-1)for SV2W10, respectively, indicating a high catalytic activity and a strong affinity of POMs towards 3,3,5,5-tetramethylbenzidine (TMB). In the case of H2O2, these values were found to be 57.1 mM and 0.325x10(-8) mMs(-1)for SVW11, and 47.7 mM and 2.72x10(-8) mMs(-1)for SV2W10. The peroxidase-like catalytic activity of these POMs was used to develop colorimetric glucose sensors as a proof-of-concept model for the POM-based naked-eye detection of biomolecules. The limit of detcetion (LOD) of glucose for SVW(11)and SV(2)W(10)was 1.14 mu M and 1.24 mu M, respectively. Our findings propose broad-ranging potential applications of these novel POMs in biosensing and bioanalytical chemistry.