Engineering Self-Calibrating Nanoprobes with Two-Photon-Activated Fluorescence Resonance Energy Transfer for Ratiometric Imaging of Biological Selenocysteine

• DOI: 10.1021/acsami.9b04555
• Publication Date: 2019-04-18T17:03:21Z
• Authors: Dailiang Zhang; Miaomiao Hu; Xi Yuan; Yongxiang Wu; Xiaoxiao Hu; Shuai Xu; Hong-Wen Liu; XiaoBing Zhang; Yanlan Liu; Weihong Tan
• Keywords: Fluorescence-lifetime imaging microscopy; Biological Imaging; Two-photon excitation microscopy

Selenocysteine (Sec) has proven to be the dominant active site of diverse selenoproteins that are directly linked with human health and disease. Thus, understanding critical functions dynamics endogenous Sec at cellular tissue levels is highly demanded. However, no method been reported capable providing reliable quantitative imaging analysis in living systems, especially deep tissues, low background signal high sensitivity resolution simultaneously. To address this challenge, we herein report a novel class engineered Sec-responsive fluorescent nanoprobes combines two-photon excitation Förster resonance energy transfer (FRET) mechanisms for direct, yet selective, sensing biological over abundant competing biothiols. Specifically, near-infrared window can minimize light scattering signals thus offering improved spatial temporal tissues reduced interference. Moreover, reasonable FRET donor–acceptor pair further designed verified by theoretical calculation. The acceptor undergoes intramolecular rearrangement specifically response nucleophilic attack Sec, hence triggering remarkable FRET-mediated ratiometric fluorescence enhancement sensitive quantification through self-calibration two emission channels. These striking properties, along good water solubility biocompatibility, suggest strategy may serve as valuable tool studying various Sec-related events complex systems.