基于芬顿反应和硫磺素T构建免标记荧光传感器用于葡萄糖的检测

基于芬顿反应和硫磺素T(ThT)构建新奇的免标记荧光传感器用于葡萄糖的检测。当无葡萄糖存在时,ThT诱导富G-DNA探针形成G-四链体/ThT复合物,ThT的荧光强度显著增强;当葡萄糖存在时,葡萄糖氧化酶催化葡萄糖产生H2 O2,在Fe^2+催化的芬顿反应作用下,H2 O2转化为羟基自由基(·OH),·OH引发DNA的氧化损伤导致富G-DNA探针裂解为短寡核苷酸片段而丧失形成G-四链体/ThT的能力,ThT的荧光强度显著降低,从而实现对葡萄糖的检测。在优化的检测条件下,G-四链体/ThT荧光强度变化和葡萄糖浓度在0.5~45μmol/L的范围内呈现较好的线性关系(R^2=0.99268),检出限为0.1μmol/L。利用本法对葡萄糖加标的血液样品进行分析,葡萄糖的回收率为90.7%~118.3%,相对标准偏差为1.7%~5.8%,方法可用于血糖检测。

A label-free glucose fluorescence biosensor by using Fenton reaction and thioflavine T-based fluorescent probe

A novel glucose fluorescence biosensor has been developed using Fenton reaction and label-free thioflavine T(ThT)-based fluorescent probe.In the absence of glucose,the ThT dye inserted the Guanine(G)-rich probe to form the G-quadruplex/ThT complex,and the fluorescence intensity of ThT was significantly increased.Upon the addition of glucose,H2O2 was generated by glucose oxidase(GOx)catalyzing the glucose.The Fe^2+-catalyzed Fenton reaction converted H2O2 to hydroxyl radical(·OH).The G-rich probe was cleaved into short oligonucleotide fragments because the hydroxyl radical(·OH)triggered DNA oxidative damage.The cleaved short oligonucleotide fragments lost the ability to form G-quadruplex/ThT,thus the fluorescence intensity dramatically decreased.The concentration of glucose was proportional to the reduced fluorescence intensity,and the glucose can be successfully analyzed by the fluorescence change of the G-quadruplex/ThT.Under the optimum experimental conditions,the fluorescence intensity decreased gradually in the glucose concentration range of 0.5-45μmol/L,exhibiting good linearity(R^2=0.99268).The detection limit of this glucose fluorescent biosensor was 0.1μmol/L.The method can be applied to quantitatively detect glucose in real blood samples.The recoveries of glucose in spiked real blood samples ranged from 90.7% to 118.3%,with relative standard deviations from 1.7%to 5.8%,showing that this method can be used for blood glucose detection.