Preparation of metal-organic framework with enzymatic cascade reaction activity for colorimetric detection of uric acid

Objective:To prepare a functional metal-organic framework(MOF)material with enzymatic cascade reaction activity for colorimetric detection of uric acid (UA) concentration in biofluids.Methods:Urate oxidase(UOx)was encapsulated by one-pot synthesis method at room temperature using 1, 3, 5-benzenetricarboxylic acid(BTC) and FeCl₃ as raw materials, so as to obtain UOx@Fe-BTC.Scanning electron microscopy (SEM), transmission electron microscopy(TEM), X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), ultraviolet-visible spectroscopy (UV-vis), Fourier-transform infrared (FT-IR) spectroscopy were used to characterize the prepared materials, identify their properties and validate the effective encapsulation of UOx.The synthesis time and pH conditions of UOx@Fe-BTC were optimized and the stability and specificity of the nanocomposite were investigated.Finally, 3, 3', 5, 5'-tetramethylbenzidine(TMB)was used for colorimetric reaction, and the concentration of UA was quantitatively detected.Results:The UOx@Fe-BTC metal-organic frame material with enzymatic cascade reaction activity was successfully prepared.At pH 3.5, the enzymatic activity was the strongest.Under the optimal condition, a well-defined linear response to UA was obtained in the concentration range of 5-800 μmol/L (R²=0.9975), with a limit of detection of 1.1 μmol/L.The commonly endogenous substances could not produce interference to UA assay.Conclusion:The functional MOF material with bi-enzyme system can provide a new technical means for UA routine monitoring and the diagnosis of clinical related diseases.