Enhanced ROS Scavenging Property of Polyoxometalates by Manganese Doping for Cytoprotection

doi:10.15541/jim20250319

Abstract

Abstract:

Excessive accumulation of reactive oxygen species (ROS) can trigger oxidative stress in cells, ultimately leading to cell death. Nanozymes, a class of nanomaterials with enzyme-like catalytic activity, are capable of scavenging ROS and protecting cells from oxidative damage. Polyoxometalates (POMs), known for their favorable redox properties and biocompatibility, have been considered as potential nanozyme candidates. However, their relatively low catalytic activity has hindered their practical applications. In this study, an isomorphic doping strategy with manganese (Mn) was employed to effectively enhance the enzyme-like activity of Keggin-type POMs ([PMo₁₂O₄₀]^3-). It was found that appropriate Mn doping significantly improved both the catalase-like (CAT-like) and superoxide dismutase-like (SOD-like) activities of the POMs, thereby enhancing its ability to eliminate excessive ROS and protect cells from oxidative stress-induced damage. The relationships among Mn doping levels, POMs structure, and catalytic activity were systematically investigated. The results suggest that the synergistic electronic interaction between Mn and Mo-O framework plays a crucial role in enhancing the CAT-like activity of the material. This work provides a preliminary exploration of design strategies for POMs-based nanozymes and offers scientific insights for the development of antioxidant nanozymes.

Key words: polyoxometalate, oxidative stress, nanozyme, catalytic medicine

CLC Number:

TQ171

QU Boxuan, TAN Ji, CHEN Shuhan, LIU Xuanyong. Enhanced ROS Scavenging Property of Polyoxometalates by Manganese Doping for Cytoprotection[J]. Journal of Inorganic Materials, 2026, 41(6): 839-846.

Figures/Tables 6

Fig. 1 Synthetic schematic of POM-Mnx samples

Fig. 2 (a) Mn content in POM-Mnx measured by ICP-OES; (b) XRD patterns, (c) TEM images, (d) Raman spectra, and (e) FT-IR spectra of POM-Mnx samples

Fig. 3 (a) Mn2p XPS spectra of POM-Mn0.1, POM-Mn0.5 and POM-Mn2.0; (b) UV-Vis absorption spectra and (c) Tauc plots of POM, POM-Mn0.1, POM-Mn0.5 and POM-Mn2.0

Fig. 4 (a) UV-Vis spectra of H2O2-Ti(SO4)2 colorimetric systems for the CAT-like activity assessment, (b) quantitative analysis of CAT-like activity, (c) dissolved oxygen generation curves, (d) CAT-like activity with or without EDTA chelation, (e) UV-Vis spectra of WST-formazan for the SOD-like activity assessment, and (f) quantitative analysis of SOD-like activity treated with POM, POM-Mn0.1, POM-Mn0.5, and POM-Mn2.0

Fig. 5 (a) Cell viability and (b) live/dead staining images of RAW264.7 cells after being treated with POM, POM-Mn0.1, POM-Mn0.5, and POM-Mn2.0 (***: p<0.001)

Fig. 6 (a) Cell viability and (b) live/dead staining images of H2O2-induced RAW264.7 cells after being treated with POM, POM-Mn0.1, POM-Mn0.5, and POM-Mn2.0 (***: p<0.001)

References 12

[1]	SIES H, BERNDT C, JONES D P. Oxidative stress. Annual Review of Biochemistry, 2017, 86: 715.
[2]	LI S, JIANG D, EHLERDING E B, et al. Intrathecal administration of nanoclusters for protecting neurons against oxidative stress in cerebral ischemia/reperfusion injury. ACS Nano, 2019, 13(11): 13382.
[3]	ZHANG C, BU W, NI D, et al. A Polyoxometalate cluster paradigm with self-adaptive electronic structure for acidity/ reducibility-specific photothermal conversion. Journal of the American Chemical Society, 2016, 138(26): 8156.
[4]	WANG Y, WU Y, WANG Z, et al. Doping strategy and mechanism for oxide and sulfide solid electrolytes with high ionic conductivity. Journal of Materials Chemistry A, 2022, 10(9): 4517.
[5]	CHEN S, LU W, XU R, et al. Pyrolysis-free and universal synthesis of metal-NC single-atom nanozymes with dual catalytic sites for cytoprotection. Carbon, 2023, 201: 439.
[6]	SHENG H X, LIN B Y, CHEN C Q, et al. From confined growth to enhanced peroxidase-like activity: nucleation of a phosphate- mediated Fe^III-Ce^III-oxo cluster inside the {P₈W₄₈} nanoreactor. Polyoxometalates, 2024, 3(3): 9140060.
[7]	LIU Q, ZHANG Q, SHI W, et al. Self-assembly of polyoxometalate clusters into two-dimensional clusterphene structures featuring hexagonal pores. Nature Chemistry, 2022, 14(4): 433.
[8]	GUMEROVA N I, ROMPEL A. Polyoxometalates in solution: speciation under spotlight. Chemical Society Reviews, 2020, 49(21): 7568.
[9]	HARDCASTLE F D, WACHS I E. Determination of molybdenum-oxygen bond distances and bond orders by Raman spectroscopy. Journal of Raman Spectroscopy, 1990, 21(10): 683.
[10]	SUN Y, FAN W, LI Y, et al. Tuning coordination structures of Zn sites through symmetry-breaking accelerates electrocatalysis. Advanced Materials, 2024, 36(4): 2306687.
[11]	ZHANG X, LI G, CHEN G, et al. Single-atom nanozymes: a rising star for biosensing and biomedicine. Coordination Chemistry Reviews, 2020, 418: 213376.
[12]	WARREN E B, BRYAN M R, MORCILLO P, et al. Manganese-induced mitochondrial dysfunction is not detectable at exposures below the acute cytotoxic threshold in neuronal cell types. Toxicological Sciences, 2020, 176(2): 446.