School of Pharmacy, Nanjing Medical University, Nanjing, Jiangsu, 211166, People's Republic of China.
Department of Laboratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, 211166, People's Republic of China.
Mikrochim Acta. 2019 Nov 20;186(12):818. doi: 10.1007/s00604-019-3820-z.
A turn-on ratiometric fluorescent assay is described for the determination of the activity of enzymes participating in ascorbic acid-forming reactions. Blue-emitting carbon dots (bCDs; with excitation/emission wavelength at 380/450 nm) serve as fluorescent indicator. Their fluorescence is reduced by Fe ions via an inner filter effect. Yellow-emitting CDs (yCDs; with excitation/emission wavelength at 380/550 nm) serve as internal reference because their fluorescence is insensitive to Fe. Upon exposure to ascorbic acid (AA), Fe is reduced to Fe. Hence, the fluorescence of the bCDs is restored. Thus, enzymes participating in AA-related reactions such as α-glucosidase (α-Glu) and alkaline phosphatase (ALP) can be determined. α-Glu activity was quantified in the range from 0.13 to 6.70 U mL, and ALP activity was determined between 2.0 and 130 U L. Endowed with excellent sensitivity, selectivity and low background signals, the method may also be used to screen the inhibitors of α-Glu and ALP. Graphical abstractSchematic representation of a redox modulated ratiometric fluorometric method based on the use of dual-color carbon dots for determination of the activity of enzymes participating in ascorbic acid-related reactions. Blue-emitting carbon dots (bCDs) serve as fluorescent indicator while yellow-emitting CDs (yCDs) serve as internal reference.
一种用于测定参与抗坏血酸形成反应的酶活性的比率型荧光比色测定法。发蓝光的碳点（bCDs；激发/发射波长为 380/450nm）用作荧光指示剂。它们的荧光通过内滤效应被 Fe 离子还原。发黄色光的碳点（yCDs；激发/发射波长为 380/550nm）用作内参，因为它们的荧光对 Fe 不敏感。暴露于抗坏血酸（AA）后，Fe 被还原为 Fe。因此，bCDs 的荧光得以恢复。因此，可以测定参与 AA 相关反应的酶，如α-葡萄糖苷酶（α-Glu）和碱性磷酸酶（ALP）。α-Glu 的活性在 0.13 至 6.70 U mL 的范围内进行定量，ALP 的活性在 2.0 至 130 U L 之间进行测定。该方法具有灵敏度高、选择性好、背景信号低等优点，也可用于筛选α-Glu 和 ALP 的抑制剂。
