School of Pharmacy, Henan University of Chinese Medicine, Zhengzhou 450046, PR China; Henan Engineering Research Center of Modern Chinese Medicine Research, Development and Application, Zhengzhou, 450046, PR China.
School of Pharmacy, Henan University of Chinese Medicine, Zhengzhou 450046, PR China.
Spectrochim Acta A Mol Biomol Spectrosc. 2024 Dec 15;323:124876. doi: 10.1016/j.saa.2024.124876. Epub 2024 Jul 23.
Nitroxyl (HNO) is an important reactive nitrogen that is associated with various states in physiology and pathology and plays a unique function in living systems. So, it is important to exploit fluorescent probes with high sensitivity and selectivity for sensing HNO. In this paper, a novel ratiometric fluorescent probe for HNO was developed utilizing intramolecular charge transfer (ICT) and fluorescence resonance energy transfer (FRET) mechanisms. The probe selected coumarin as energy donor, naphthalimide as energy receptor and 2-(diphenylphosphino)benzoate as the sensing site for detecting HNO. When HNO was not present, the 2-(diphenylphosphino)benzoate unit of the probe restricted electron transfer and the ICT process could not occur, leading to the inhibition of FRET process as well. Thus, in the absence of HNO the probe displayed the intrinsic blue fluorescence of coumarin. When HNO was added, the HNO reacted with the 2-(diphenylphosphino)benzoate unit of the probe to yield a hydroxyl group which resulting in the opening of ICT process and the occurring of FRET process. Thus, after providing HNO the probe displayed yellow fluorescence. In addition, the probe showed good linearity in the ratio of fluorescence intensity at 545 nm and 472 nm (I/I) with a concentration of HNO (0.1-20 μM). The probe processed a detection limit of 0.014 μM and a response time of 4 min. The probe also specifically identified HNO over a wide pH scope (pH = 4.00-10.00), including physiological conditions. Cellular experiments had shown that this fluorescent probe was virtually non-cytotoxic and could be applied for ratiometric sensing of HNO in A549 cells.
硝酰基（HNO）是一种重要的反应性氮，与生理和病理的各种状态有关，并在生命系统中发挥独特的功能。因此，开发具有高灵敏度和选择性的用于检测 HNO 的荧光探针非常重要。在本文中，我们利用分子内电荷转移（ICT）和荧光共振能量转移（FRET）机制开发了一种新型的用于检测 HNO 的比率型荧光探针。该探针选择香豆素作为能量供体，萘酰亚胺作为能量受体，2-(二苯基膦基)苯甲酸作为检测 HNO 的传感位点。当不存在 HNO 时，探针的 2-(二苯基膦基)苯甲酸单元限制了电子转移，ICT 过程无法发生，导致 FRET 过程也受到抑制。因此，在不存在 HNO 的情况下，探针显示出香豆素的固有蓝色荧光。当加入 HNO 时，HNO 与探针的 2-(二苯基膦基)苯甲酸单元反应生成羟基，导致 ICT 过程的开启和 FRET 过程的发生。因此，提供 HNO 后，探针显示出黄色荧光。此外，该探针在 545nm 和 472nm 处荧光强度的比值（I/I）与 HNO 的浓度（0.1-20μM）之间表现出良好的线性关系。该探针的检测限为 0.014μM，响应时间为 4 分钟。该探针还能在较宽的 pH 范围（pH=4.00-10.00）内特异性识别 HNO，包括生理条件。细胞实验表明，这种荧光探针几乎没有细胞毒性，可用于 A549 细胞中 HNO 的比率型传感。
