Copper-ion-complexed palygorskite as a novel nanozyme with enhanced peroxidase-like activity for sensitive colorimetric sensing

A novel nanozyme, based on copper-ion-complexed palygorskite (Pal Cu ²⁺), was synthesized using a facile method. The introduction of Cu ²⁺ demonstrates a synergistic effect with Pal, enhancing the peroxidase-like activity for the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H ₂O ₂. Steady-state kinetic analysis revealed that Pal Cu ²⁺ exhibits a higher affinity for substrates compared to native horseradish peroxidase, presenting a practical alternative to natural peroxidase. The efficacy of Pal Cu ²⁺ as a peroxidase mimic for H ₂O ₂ sensing was investigated through colorimetric methods. Additionally, when combined with enzymatic glucose oxidation, a sensitive and selective colorimetric strategy for glucose detection was established. The developed method was effectively applied to detect H ₂O ₂ and glucose in real samples. The proposed strategy offers an approach for the rational design and development of metal ion composites, opening new way for future applications of Pal-based materials.