Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001, India.
School of Basic Sciences, Indian Institute of Technology Mandi, Kamand, Mandi, Himachal Pradesh-175005, India.
Analyst. 2018 Sep 21;143(18):4476-4483. doi: 10.1039/c8an01136b. Epub 2018 Aug 29.
Tyrosinase is polyphenolic oxidase enzyme associated with the progression of various diseases. Therefore, for the recognition of tyrosinase, naphthalimide-based ratiometric fluorescent sensor probe was designed and synthesized. 3-Hydroxyphenyl, as the substrate unit for the enzyme, is an important feature of this design, which avoids the interference of other bio-analytes for the recognition of tyrosinase. When the sensor probe was excited at 425 nm, an intense blue emission band emerged at 467 nm. However, upon the addition of tyrosinase to the probe solution, the monophenolic unit oxidized to o-dihydroxy and consequently released the 4-aminonaphthalimide unit. As the oxidation reaction proceeded, the fluorescence emission at 535 nm started to increase gradually with an increase in the concentration of enzyme. Therefore, the sensor probe gives the ratiometric changes via fluorescence spectroscopy. The probe affords high selectivity and sensitivity to tyrosinase with a detection limit of 0.2 U mL. Furthermore, live cell images were recorded to assay the endogenous enzyme in A375 cells, which also show a dual color change in the presence of the L3 probe.
酪氨酸酶是与多种疾病进展相关的多酚氧化酶。因此，为了识别酪氨酸酶，设计并合成了基于萘酰亚胺的比率荧光传感器探针。3-羟基苯基作为酶的底物单元，是该设计的一个重要特点，它可以避免其他生物分析物对酪氨酸酶识别的干扰。当传感器探针在 425nm 激发时，在 467nm 处出现强的蓝色发射带。然而，当将酪氨酸酶添加到探针溶液中时，单酚单元被氧化为邻二羟基，并因此释放出 4-氨基萘酰亚胺单元。随着氧化反应的进行，535nm 处的荧光发射逐渐开始增加，同时酶的浓度也在增加。因此，传感器探针通过荧光光谱给出了比率变化。该探针对酪氨酸酶具有高选择性和灵敏度，检测限为 0.2U mL。此外，还记录了活细胞图像以测定 A375 细胞中的内源性酶，在存在 L3 探针的情况下，也显示出双颜色变化。
