Novel near‑infrared fluorescent probe for live cell imaging

Abstract

Near infrared (NIR) fluorescent probes play a crucial role in biological system imaging. A novel NIR fluorescent probe, IR787, was designed in the present study. Compared with indocyanine green (ICG), IR787 showed lower background fluorescent interference and higher fluorescence enhancement. Fluorescence intensities were detected by a Cary Eclipse fluorescence spectrophotometer. The interference of intracellular ions (Cu 2+ , Ca 2+ , Mg 2+ and Zn 2+) on the measurement was negligible, which indicated a good photostability of IR787. MTT assay demonstrated that cell viability of human lung adenocarcinoma epithelial cell line A549 was not significantly affected by the use of the IR787 probe compared with the ICG probe. This result suggested that the IR787 probe was safe for in vitro cell imaging. In vitro NIR optical imaging experiments further revealed cellular uptake and strong intracellular NIR fluorescence of the IR787 probe in A549 cells. The excitation wavelength was 787 nm for IR787. Compared with the previously reported NIR fluorescent probe ICG, the IR787 NIR fluorescent probe had improved prospects for intracellular imaging. IR787 may play a pivotal role in the understanding cell biology, pharmacology and disease diagnosis.

ClO– Induced Dual-Excitation Fluorescent Probes Responding to Diverse Testing Modes with Ratio Methodology

“…), has attracted enormous research interest among molecular biological studies. This is because excessive oxidative small molecules can cause DNA damage and gene mutation, and play negative impacts on the modification process of protein in living organisms. , With the advantages of noninvasive, highly responsive, and real-time monitoring properties, fluorescent probes can be used for certain experimental detection/monitoring purposes of the as-mentioned oxidative small molecules in diverse complex systems, such as the recognition and real-time monitoring of ClO – (refs – ) or H 2 O 2 . , Considering the complex environment in living organisms, one fluorescent probe must be optimized to meet the changes in diverse detection environments with superior data calibration or comparison methodology, and to determine/assess the content changes of active small molecules in both accurate detection in vitro and imaging in vivo, − e.g., for the detection of biological samples or blood samples in vitro, fluorescent probes need achieve high response activity; meanwhile, for imaging in vivo, fluorescent probes that monitor the process of small molecule changes must show satisfactory tissue penetration depth and spatial resolution.…”