Institute of Drug Discovery Technology, Ningbo University, Ningbo, China.
Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2023 Dec 5;302:123032. doi: 10.1016/j.saa.2023.123032. Epub 2023 Jun 20.
Overexpressed nitroreductase (NTR) is often utilized to evaluate the hypoxic degree in tumor tissues, thus it is of great importance to develop high selective and efficient optical method to detect NTR. The dynamic fusion and function of lysosome promoted us to explore the possible appearance of NTR inside this organelle and to probe its behavior in a cellular context. In this work, a ratiometric fluorescent probe based on an extended π-π conjugation of a triphenylamine unit was designed for NTR detection and lysosomes imaging. The dual-emission mechanism of the probe in the presence of catalytic NTR was confirmed by theoretical study. The structure-function relationship between probe and NTR was revealed by docking calculations, suggesting a suitable structural and spatial match of them. The photophysical studies showed the probe had high selectivity, rapid response and a wide pH range towards NTR. MTT assay indicated the probe had low cytotoxicity in both normal (HUVEC) and tumor (MCF-7) cells. Furthermore, the inverse fluorescent imaging results confirmed the probe was NTR-active and exhibited time- and concentration-dependent fluorescence signals. In addition, the relatively high Pearson's correlation coefficient (0.99 in HepG2 and 0.97 in MCF-7 cells, compared to Lyso-Tracker Red) demonstrated the probe had excellent lysosomes colocalization. This study illustrates a ratiometric detection of NTR agent for lysosomes fluorescent imaging, which may provide a novel insight in molecular design.
过表达的硝基还原酶（NTR）常用于评估肿瘤组织的缺氧程度，因此开发高选择性和高效的光学方法来检测 NTR 非常重要。溶酶体的动态融合和功能促使我们探索 NTR 可能出现在该细胞器内部，并在细胞环境中探测其行为。在这项工作中，设计了一种基于三苯胺单元扩展 π-π 共轭的比率荧光探针，用于 NTR 检测和溶酶体成像。通过理论研究证实了探针在存在催化 NTR 时的双发射机制。通过对接计算揭示了探针与 NTR 之间的结构-功能关系，表明它们具有合适的结构和空间匹配。光物理研究表明，探针对 NTR 具有高选择性、快速响应和宽 pH 范围。MTT 测定表明，探针在正常（HUVEC）和肿瘤（MCF-7）细胞中均具有低细胞毒性。此外，反向荧光成像结果证实该探针是 NTR 活性的，并表现出时间和浓度依赖性的荧光信号。此外，较高的皮尔逊相关系数（HepG2 中的 0.99 和 MCF-7 细胞中的 0.97，与 Lyso-Tracker Red 相比）表明探针具有出色的溶酶体共定位。这项研究说明了用于溶酶体荧光成像的 NTR 比率检测探针，这可能为分子设计提供新的见解。
