Hemicyanine-Based Near-Infrared Fluorescence Off–On Probes for Imaging Intracellular and In Vivo Nitroreductase Activity
Nitroreductase (NTR) has the ability to activate nitro group-containing prodrugs and decompose explosives; thus, the evaluation of NTR activity is specifically important in pharmaceutical and environmental areas. Numerous studies have verified effective fluorescent methods to detect and image NTR ac...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-03-01
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| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/24/7/6074 |
| Summary: | Nitroreductase (NTR) has the ability to activate nitro group-containing prodrugs and decompose explosives; thus, the evaluation of NTR activity is specifically important in pharmaceutical and environmental areas. Numerous studies have verified effective fluorescent methods to detect and image NTR activity; however, near-infrared (NIR) fluorescence probes for biological applications are lacking. Thus, in this study, we synthesized novel NIR probes (<b>NIR-HCy-NO<sub>2</sub> 1–3</b>) by introducing a nitro group to the hemicyanine skeleton to obtain fluorescence images of NTR activity. Additionally, this study was also designed to propose a different water solubility and investigate the catalytic efficiency of NTR. <b>NIR-HCy-NO<sub>2</sub></b> inherently exhibited a low fluorescence background due to the interference of intramolecular charge transfer (ICT) by the nitro group. The conversion from the nitro to amine group by NTR induced a change in the absorbance spectra and lead to the intense enhancement of the fluorescence spectra. When assessing the catalytic efficiency and the limit of detection (LOD), including NTR activity imaging, it was demonstrated that <b>NIR-HCy-NO<sub>2</sub> 1</b> was superior to the other two probes. Moreover, we found that <b>NIR-HCy-NO<sub>2</sub> 1</b> reacted with type I mitochondrial NTR in live cell imaging. Conclusively, <b>NIR-HCy-NO<sub>2</sub></b> demonstrated a great potential for application in various NTR-related fields, including NTR activity for cell imaging in vivo. |
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| ISSN: | 1661-6596 1422-0067 |