Polyoxometalate-based Nanozyme For The Detection Of Biomolecules

In recent years,the emergence of nanozymes has attracted attention from researchers.Natural enzymes suffer from drawbacks such as instability,difficulty in purification,and challenges in recovery and storage.In comparison,nanozymes exhibit stable physicochemical properties,easy recyclability,simple preparation,and low cost,making them widely applicable in various fields.Polyoxometalates are metal oxide clusters with diverse structures,suitable for homogeneous catalysis and good biocompatibility.Nanozyme materials with enzyme-like activity based on polyoxometalates can be the candidates for natural enzymes.In this dissertation,various polyoxometalate-based nanomaterials were prepared.The structure,morphology,and elemental composition of the prepared materials were analyzed by different techniques.Enzyme-like activity of the polyoxometalate-based nanomaterials was determined,and all of the ten nanozyme materials exhibited peroxidase-like activity.The catalytic activity and optimal reaction conditions of the nanozymes were investigated.Comparing with the other four mono-metal-substituted polyoxometalate-based nanozymes H₇PMo₁₁Co O₄₀,H₆PMo₁₁Ni O₄₀,H₇PMo₁₁Cu O₄₀and H₇PMo₁₁Zn O₄₀,iron-substituted polyoxometalate-based nanozyme H₆PMo₁₁FeO₄₀showed better peroxidase-like activity.Further studies were carried out on four iron-substituted POM-based nanozymes K₇P₂Fe（OH₂）W₁₇O₆₁,K₁₀P₂W₁₈Fe₄（H₂O）₂O₆₈,Na₉K[(FeW₉O₃₄)₂Fe₄（H₂O）₂],H₂Na₁₄[Fe₂^III（Na OH₂）₂(P₂W₁₅O₅₆)₂],among which Na₉K[(FeW₉O₃₄)₂Fe₄（H₂O）₂]exhibited high catalytic activity but also higher cytotoxicity.In addition,[Mo₇₂Fe₃₀]polyoxometalate-based nanozyme was also successfully prepared,showing high peroxidase-like activity and good antibacterial performance,with a synergistic antibacterial capability of up to 75%with low concentration of H₂O₂.Nonenzymatic sensors towards hydrogen peroxide detection were constructed based on H₆PMo₁₁FeO₄₀,Na₉K[(FeW₉O₃₄)₂Fe₄（H₂O）₂],or[Mo₇₂Fe₃₀]nanozymes,which exhibited wide linear ranges and low detection limits,and hold practical significance in diverse fields including analytical detection,environmental monitoring,and cancer antibacterial therapy.