A novel dual-excitation and dual-emission fluorescent probe (CQDs-O-NBD) based on carbon quantum dots for detection and discrimination of Cys/Hcy and GSH/H2S in living cells. (September 2021)

• Record Type: Journal Article
• Authors: Zhang, Jie; Jia, Haishuang; Liu, Wenfang; Wang, Jun; Fang, Dawei
• Is Part Of: Dyes and pigments. Volume 193(2021)
• Publication Date: 2021-09
• Subjects: Fluorescent probe -- Carbon quantum dots -- NBD -- Dual-excitation -- Dual-emission -- Biothiols detection; Dyes and dyeing -- Periodicals; Pigments -- Periodicals; 667.2
• DOI: 10.1016/j.dyepig.2021.109554
• Languages: English
• ISSNs: 0143-7208

Abstract

Abstract: Cysteine (Cys), homocysteine (Hcy), glutathione (GSH) and hydrogen sulfide (H2 S) are essential active substance in human body. The identification and detection of biothiols and H2 S are of great significance for the early diagnosis of certain diseases. In this paper, a new dual excitation and dual emission fluorescent probe, carbon quantum dot-O-7-nitrobenzo-2-oxa-1, 3-diazole (CQDs-O-NBD), for the detection of biothiols and H2 S was synthesized. The carbon quantum dots (CQDs-OH) (λex/em maxima = 377 nm/467 nm) were synthesized by a microwave-assisted method using hydroquinone as the carbon source. Through the reaction of the phenolic hydroxyl group of the carbon quantum dots and 4-chloro-7-nitrobenzo-2-oxa-1, 3-diazole (NBD-Cl), the CQDs-O-NBD was synthesized. Due to the static quenching (SQ) and the photo-induced electron transfer (PET) from CQDs to NBD, the fluorescence of the CQDs-O-NBD is very weak. After adding biothiols and H2 S, the ether bond of the CQDs-O-NBD was broken through nucleophilic substitution reaction, which led to the release of the CQDs-OH (channel 1 is turned on) and generation of a new compound NBD-thiols (channel 2). The CQDs-O-NBD as a probe shows the high selectivity and sensitivity for Cys/Hcy/GSH/NaHS (LOD of 0.24 μM/0.21 μM/0.19 μM/0.18 μM) over other aminos and ions by channel 1. The new formed compounds from NBD and Cys/Hcy have strong fluorescence under 470 nm wavelength light excitation (channel 2 is turned on), while the formed compounds from NBD and GSH/NaHS have no fluorescence (no channel 2), so the CQDs-O-NBD can discriminate Cys/Hcy (LOD: 0.07 μM/0.06 μM) from GSH/NaHS. In addition, the CQDs-O-NBD shows low toxicity and can be applied to the detection of Cys in fetal bovine serum and imaging in living cells. Graphical abstract: Image 1 Highlights: A dual-excitation dual-emission CQDs-O-NBD is synthesized for detecting biothiols. CQDs-O-NBD can identify biothiols from other substances in channel 1 (λem = 467 nm). CQDs-O-NBD can discriminate Cys/Hcy from GSH/H2 S in channel 2 (λem = 546 nm). CQDs-O-NBD both shows low LODs for biothiols detection at two excitation wavelengths. CQDs-O-NBD can be applied to sensitively track biothiols in Hela cells.