基于封装酶的金属有机框架纳米酶级联催化实现鱼肉中次黄嘌呤的可视化检测

Enzyme-encapsulated metal-organic framework nanozyme cascade catalysis enables visual determination of hypoxanthine in fish

目的基于金属有机框架(metal-organic framework,MOF)封装黄嘌呤氧化酶(xanthine oxidase,XOD)构建纳米酶级联催化体系,实现次黄嘌呤(hypoxanthine,Hx)的可视化检测。方法室温下采用一步法仿生矿化工艺将天然酶XOD封装于1,4-苯二甲酸铜(copper 1,4-benzenedicarboxylate,CuBDC)MOF纳米酶中,制备封装酶的金属有机框架材料(XOD@CuBDC),探究其过氧化物酶活性及级联催化性能。通过最适反应条件的优化,建立颜色强度与Hx浓度的标准曲线,考察该方法对鱼肉中Hx的检测。结果与使用游离XOD和CuBDC组成的级联反应系统比较,XOD@CuBDC催化速度更快,显色强度更强,酶储存更稳定。该体系的颜色强度与Hx浓度在0.015~0.470 mmol/L范围内具有线性关系(r^(2)>0.99),方法检出限(S/N=3)为10.47μmol/L。应用于不同新鲜程度的牙鲆鱼肉中Hx含量测定,结果与高效液相色谱法呈线性关系,相关性为0.98865。结论构建的XOD@CuBDC纳米酶级联催化体系具有良好的稳定性和催化性能,能够用于鱼肉中Hx的快速检测。

Objective To construct a nanozyme cascade catalytic system based on xanthine oxidase(XOD)encapsulated in metal-organic framework(MOF),and realize visual detection of hypoxanthine(Hx).Methods The natural enzyme XOD was encapsulated in the MOF nanoenzyme of copper 1,4-benzenedicarboxylate(CuBDC)via a one-step biomimetic mineralization process at room temperature.Its peroxidase activity and cascade catalytic performance was evaluated.At the optimal reaction conditions,the standard curve of color intensity and Hx concentration was established,and the detection of hypoxanthine in fish meat was investigated.Results Compared with the cascade reaction system using free XOD and CuBDC,the catalytic speed of XOD@CuBDC was faster;the color intensity was stronger;the enzyme was more stable.The color intensity of the system had a linear relationship with Hx concentration in the range of 0.015-0.470 mmol/L(r^(2)>0.99),and the limit of detection(S/N=3)was 10.47μmol/L.The results showed a good linear relationship with the results of high performance liquid chromatography with the correlation of 0.98865 when the method was applied to detect Hx content in fish.Conclusion The constructed Hx XOD@Cu BDC nanoenzyme has good stability and cascade catalytic effect,and can be used for the rapid detection of Hx in fish.