酪胺修饰石墨烯量子点检测血清中游离胆固醇

以柠檬酸为原料合成具有模拟过氧化氢酶活性的石墨烯量子点(GQDs),经酪胺修饰的GQDs(TYR-GQDs)可以将过氧化氢还原成羟基自由基,通过酚羟基之间的交联聚集,GQDs的荧光被猝灭。由于胆固醇氧化酶可以催化胆固醇氧化生成H_2O_2,因此,基于TYR-GQDs建立了一种检测胆固醇的荧光传感器。在pH=7.4的条件下,TYR-GQDs的荧光猝灭率与胆固醇浓度(2.67×10~(-8)～2.67×10~(-3)mol/L)的对数呈良好的线性关系,检出限为9.32×10~(-9)mol/L。干扰实验表明,该荧光传感器对胆固醇具有高度的选择性,可以用于人体血清中游离胆固醇的检测,加标回收率为96.55%～100.14%。

Determination of Free Cholesterol in Serum by Tyramine Modified Graphene Quantum Dots

Cholesterol level is closely related to human health. If the cholesterol level in human body exceeds the normal level, it will cause a series of cardiovascular diseases. The current detection technology needs expensive instruments, advanced analysis technology or detection time is long and not sensitive enough, so it is urgent to need a simple, fast, cheap and high sensitivity detection method. In this study, graphene quantum dots (GQDs) with catalase like activity were synthesized from citric acid. The graphene quantum dots modified by tyramine (TYR-GQDs) can reduce hydrogen peroxide to hydroxyl radicals. Through cross-linking and aggregation between phenolic hydroxyls, the fluorescence of GQDs was quenched. Because cholesterol oxidase can catalyze the oxidation of cholesterol to H₂O₂, a fluorescence sensor based on TYR-GQDs was developed to detect cholesterol. The experimental results showed that the fluorescence quenching rate of TYR-GQDs had a good linear relationship with the logarithm of cholesterol concentration (2.67×10^_-8-2.67×10^_-3 mol/L), and the detection limit was 9.32×10^_-9 mol/L, under the condition of pH=7.4. The interference experiment showed that the fluorescent sensor had high selectivity for cholesterol, and can be used for the detection of free cholesterol in human serum. The recovery of standard addition was 96.55%-100.14%.