A colorimetric and fluorescent dual probe for specific detection of cysteine based on intramolecular nucleophilic aromatic substitution

Abstract

4-Nitro-1,8-naphthalic anhydride (NNA) was used to distinguish cysteine from homocysteine and other potentially interfering thiols through a novel sequential substitution mechanism. The discrimination involves a blue-fluorescent thioether formation via nucleophilic aromatic substitution of the nitro group by thiol, followed by a second intramolecular nucleophilic aromatic substitution of alkylthio with the amino group to give the green-fluorescent 4-amino derivative. NNA is highly selective towards Cys, and the detection limit of Cys by this method is 0.3 μM.

One-pot synthesis of a new rhodamine-based dually-responsive pH sensor and its application to bioimaging

“…The result showed that RPBD reversibly coordinated with H þ (Scheme 2), as depicted in the literature. 18,20,32 To verify the proposed sensing mechanism, LCeMS of the CH 3 Fig. 6 well supported the proposed sensing mechanism, as well as confirmed the structure of RPBD in extreme acidity (pH<4).…”

Design strategies of fluorescent probes for selective detection among biothiols

“…In their early work, probe 53 was employed to detect Cys, but only at 50 1C and in DMF because of the low reactivity of 53, which precluded its use in biological systems. 86 To improve the detection kinetics, they designed probes 54a-c based on naphthalimide-bearing View Article Online electron-withdrawing heterocycles. 87 The most active probe, 54c, discriminated between GSH and Cys: 54c reacted with GSH to generate a highly fluorescent thioether (l em = 498 nm, l abs = 402 nm), with the fluorescence intensity at 498 nm linearly proportional to GSH concentrations in the range of 0-20 mM, and the detection limit was 5 Â 10 À8 M. In the case of Cys, the amino product (l em = 521 nm, l abs = 446 nm) was only weakly fluorescent.…”

A ratiometric fluorescent probe for cysteine and its application in living cells

“…Compared to single wavelength response fluorescent probes, ratiometric fluorescent probes have two emission wavelengths to give a built-in correction for probe concentration and measured environment effects [41,42]. Although significant advances of fluorescent probes for Cys have been made [16,[43][44][45][46][47], the ratiometric probes are still rare [17,21,38,48].…”