具有过氧化物酶活性的Co-MOFs衍生物用于L-Cys的比色和智能手机双模检测

Co-MOFs derivatives with peroxidase activity are used for colorimetric and smartphone dual-mode detection of L-Cys

摘要:

为了实现对L-半胱氨酸（L-Cys）的简便、快速、低成本和可视化检测，通过室温合成-热解法制备了一种具有类过氧化物酶性质的金属钴有机框架衍生纤维棒状碳材料（Co-DM）。利用SEM、TEM、XRD和XPS等手段对其形貌、结构及元素组成进行了表征。通过活性氧捕获实验研究了其催化机理，Co-DM可催化H2O2使其释放出超氧阴离子（O2·?）和羟基自由基（·OH），从而使无色的显色底物3,3',5,5'-四甲基联苯胺（TMB）氧化成蓝色的oxTMB，在652 nm处有最大的紫外吸收峰；而L-Cys具有抗氧化性，能够还原oxTMB使蓝色褪色。基于此原理建立了一种检测L-Cys的比色检测方法。在最优化条件下，L-Cys的浓度与吸光度在0.1~15.0 μmol/L范围呈线性关系，检出限（LOD）为0.35 μmol/L。此外，借助自制的智能手机光学设备和Color Garb软件，通过记录不同浓度L-Cys下溶液在白色（0,0,0）至黑色（255,255,255）范围内颜色变化的特征值R（红）、G（绿）、B（蓝）值，建立了L-Cys的相对活性与颜色特征值的定量关系，检测范围为0.1~70.0 μmol/L，LOD为0.27 μmol/L。该方法还成功地应用于临床人血清中L-Cys的检测，回收率超过96%。结果表明，基于Co-DM催化TMB-H2O2体系构建的比色传感在L-Cys的测定方面具有灵敏、快速且无需昂贵设备的广阔前景。

Abstract:

A metal-cobalt organic framework-derived fibrous rod-like carbon material (Co-DM) with peroxidase-like properties was prepared by a room-temperature synthesis-pyrolysis method in order to achieve a simple, rapid, low-cost and visual detection of L-cysteine (L-Cys). Its morphology, structure and elemental composition were characterized by SEM, TEM, XRD and XPS. The catalytic mechanism of reactive oxygen species was investigated, and Co-DM catalyzed H2O2 to release superoxide anions (O2·?) and hydroxyl radicals (·OH), thereby oxidizing the colorless chromogenic substrate 3,3',5,5'-tetramethylbenzidine (TMB) to blue oxTMB, performing UV-vis spectrophotometer detection at 652 nm, and recording the colorimetric signal. L-Cys has antioxidant properties and can reduce oxTMB to fade the blue color of the solution. Based on this principle, a colorimetric detection method for the detection of L-Cys was established. Under the optimal conditions, the concentration of L-Cys has a linear relationship with the absorbance in the range of 0.1~15.0 μmol/L, and the detection limit (LOD) is 0.35 μmol/L. In addition, the quantitative relationship between the relative activity of L-Cys and the color characteristic values was established by recording the characteristic values R (red), G (green), and B (blue) values of color change in the range of white (0,0,0) to black (255,255,255) for solutions at different concentrations of L-Cys with the aid of a homemade smartphone optical device and Color Garb software. The detection range was 0.1~70.0 μmol/L and the LOD was 0.27 μmol/L. This method was successfully applied to the detection of L-Cys in clinical human serum, and the recovery rate exceeded 96%. The results show that colorimetric sensing based on Co-DM catalyzed TMB-H2O2 system has broad prospects for the determination of L-Cys, which is sensitive, fast and does not require expensive equipment.