Fluorescence “on–off–on” peptide-based chemosensor for the selective detection of Cu²⁺ and S²⁻ and its application in living cell bioimaging

Abstract

Copper ions are known to be very important for homeostasis, which is critical for the metabolism and development of living organisms. In addition, sulfide ions, as an important endogenously produced gasotransmitter, have been proved to be implicated in a variety of physiological functions such as anti-apoptosis, vasodilation, antioxidation, and anti-inflammation. Herein, we report the development of a novel fluorescence chemosensor (L) based on a tetra-peptide conjugated with dansyl groups as a promising analytical tool for detecting Cu and S in 100% aqueous solutions, which exhibits excellent cell biotoxicity and intracellular biosensing ability. The chemosensor L displays an "on-off-on" response type fluorescence change upon the addition of Cu and S to aqueous media and living cells. Moreover, L displays high selectivity and sensitivity with the detection limits for Cu and S measured to be 88 nM and 75 nM, respectively. This study raises the new possibility of a highly selective and sensitive peptide-based fluorescence chemosensor for multifunctional detection, including cation and anions, using a successive fluorescence response strategy in environmental and biological systems.

A Highly Selective “On‐Off‐On” Optical Switch for Sequential Detection of Cu2+and S2−Ions Based on 2, 6‐Diformyl‐4‐methyl Phenol and Catecholase Activity by Its Copper Complex

“…In this regard, several examples of fluorometric as well as colorimetric sensors for copper ion with remarkable changes in their absorption or emission properties have been reported during recent years ,. However, upon binding with Cu 2+ some sensors undergo fluorescence quenching due to the inherent paramagnetic nature of Cu 2+ and this issue is generally considered as a defect in fluorescent Cu 2+ sensing . More interestingly, the non‐fluorescent Cu 2+ complex has potential utility in the selective recognition of anion by the displacement approach through the implication of the Cu‐complex as secondary molecular sensor ,…”

Multifunctional peptide‐based fluorescent chemosensor for detection of Hg2+, Cu2+ and S2− ions

“…This fluorescent peptide probe can differentiate Cu 2+ and Hg 2+ by different response types, performing a turn‐on response to Hg 2+ and a turn‐off response to Cu 2+ . Tang and colleagues reported two novel peptide fluorescent chemosensors that exhibited fluorescence quenching responses for Cu 2+ and Hg 2+ , and that distinguished these two heavy metal ions by the same response type …”

“…The design of effective probes for monitoring S 2− is significant because abnormal levels of S 2− have been associated with increased risk of many diseases, however peptide‐based sensors for S 2− detection are rarely reported. Recently, Tang and colleagues described a novel peptide‐based fluorescence sensor for detection of Cu(II) and S 2− . These chemosensors display an ‘on–off–on’ fluorescence response change on the addition of Cu 2+ and S 2− to aqueous solution, however these sensors were often affected by Hg(II) when selectively detecting Cu(II) .…”

“…Recently, Tang and colleagues described a novel peptide‐based fluorescence sensor for detection of Cu(II) and S 2− . These chemosensors display an ‘on–off–on’ fluorescence response change on the addition of Cu 2+ and S 2− to aqueous solution, however these sensors were often affected by Hg(II) when selectively detecting Cu(II) . In this study, we synthesized a new multifunctional chemosensor based on a pentapeptide, dansyl‐Gly‐His‐Gly‐Gly‐Trp‐COOH (D‐P5), to monitor Hg(II) and Cu(II) and especially S 2− .…”

A Simple Perceptive Diphenyl‐Imidazole‐Based Dipodal Schiff‐Base Chemosensor for Zn2+ and PPi ions and Its Live‐Cell Imaging Applications

“…Therefore, the development of sensors for recognition of phosphate anion is also of great importance. The transition metal complexes have been reported as good candidates for the recognition of anions because structural and geometrical flexibility of metal centers in such complexes can provide excellent way for anion binding . In this connection, zinc complexes have been found to be the most successful ones owing to the strong binding affinity between zinc ion and PPi ion .…”