基于碳量子点光活性模拟酶性能灵敏检测焦磷酸根离子

摘要

The highly solubile and photocatalytic carbon quantum dots(CDs) were prepared by a onepot hydrothermal method.The CDs could oxidize the typical substrate of 3,3',5,5'-tetramethylbenzidine (TMB) of the horseradish peroxidase (HRP) under visible light (A ≥ 400 nm) irradiation causing the color signal.In this assay,the interaction between copper ion and CDs will suppress the oxidase mimicking activity of CDs.Upon introduction of target pyrophosphate ions(ppi) into the detection system,the Cu2+-ppi complexes were forming on the basis of the coordination reaction between copper ion and inorganic pyrophosphate ions,thus the oxidase mimicking activity of released CDs was recovered.Based on this characteristic,a colorimetric sensor for the ppi detection was designed.Under the optimal conditions,the obtained colorimetric signal showed a linear response to ppi within a dynamic range of 1.0 × 10-6 _ 5.0 × 10-3 mol/L with a detection limit(LOD) of 2.5 ×10-7 mol/L.The method was applied in the determination of ppi in human plasma samples,with recoveries of 97.4％ 104.8％.The results showed that the colorimetric sensor could be used to detect ppi in human plasma samples.%利用简单的水热法合成了具有良好水溶性、优良光活性模拟酶性质的碳量子点(CDs),该量子点在可见光照(A≥400 nm)下可以催化氧化辣根过氧化物酶(HRP)的特征底物3,3',5,5'-四甲基联苯(TMB),生成与HRP催化氧化相同的产物.铜离子可与CDs发生配位作用,使CDs聚集光诱导模拟酶的活性降低;焦磷酸根(ppi)存在时,铜离子与ppi配位生成Cu2-ppi复合物,从而使CDs分散模拟酶活性恢复.利用这一现象建立了一种比色检测ppi的方法,在最佳条件下,检测信号与ppi的浓度之间存在良好的线性关系,其线性范围为1.0×10-6～5.0×10-3 mol/L,检出限为2.5×10-7 mol/L.将该方法应用于健康人血浆中ppi的检测,ppi的回收率为97.4％ ～ 104.8％,研究表明该比色传感器可用于人血浆中ppi的检测.