American Chemical Society
ja2c10041_si_001.pdf (3.31 MB)

Polymethine Molecular Platform for Ratiometric Fluorescent Probes in the Second near-Infrared Window

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journal contribution
posted on 2022-10-25, 16:03 authored by Qingchun Lan, Peng Yu, Kui Yan, Xiaomin Li, Fan Zhang, Zuhai Lei
Visualizing biomolecules such as enzymes in the deep tissue of living organisms via molecular ratiometric fluorescent probes in the second near-infrared window (NIR-II) with a built-in self-calibration function can provide reliable information about relevant pathophysiological processes directly but so far is not feasible due to the lack of a fluorescence modulation strategy in the NIR-II window. Here we present a molecular platform Py-2 by integrating the rhodamine 6G scaffold and polymethine. The maximal emission wavelength of Py-2 was 1010 nm and blue-shifted to 945 nm when its secondary amine was acylated. Based on Py-2, two molecular ratiometric NIR-II fluorescent probes, nitroreductase-responsive Rap-N and ROS-responsive Rap-R, were constructed and successfully demonstrated in vitro and in vivo. Overall, this report presents a unique approach to developing ratiometric NIR-II molecular probes for in vivo biosensing.