Design strategies for water-soluble small molecular chromogenic and fluorogenic probes.

Detection Ying Zhou,†,‡ Jun Feng Zhang, and Juyoung Yoon*,† †Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea ‡Key Laboratory of Medicinal Chemistry for Natural Resource, School of Chemical Science and Technology, Yunnan University, Kunming, 650091, P. R. China College of Chemistry and Chemical Engineering, Yunnan Normal University, Kunming 650500, P. R. China

Fluorescence and colorimetric chemosensors for fluoride-ion detection.

Hydrogen sulfide (H2S), a gaseous species produced by both bacteria and higher eukaryotic organisms, including mammalian vertebrates, has attracted attention in recent years for its contributions to human health and disease. H2S has been proposed as a cytoprotectant and gasotransmitter in many tissue types, including mediating vascular tone in blood vessels as well as neuromodulation in the brain. The molecular mechanisms dictating how H2S affects cellular signaling and other physiological events remain insufficiently understood. Furthermore, the involvement of H2S in metal-binding interactions and formation of related RSS such as sulfane sulfur may contribute to other distinct signaling pathways. Owing to its widespread biological roles and unique chemical properties, H2S is an appealing target for chemical biology approaches to elucidate its production, trafficking, and downstream function. In this context, reaction-based fluorescent probes offer a versatile set of screening tools to visualize H2S pools in living systems. Three main strategies used in molecular probe development for H2S detection include azide and nitro group reduction, nucleophilic attack, and CuS precipitation. Each of these approaches exploits the strong nucleophilicity and reducing potency of H2S to achieve selectivity over other biothiols. In addition, a variety of methods have been developed for the detection of other reactive sulfur species (RSS), including sulfite and bisulfite, as well as sulfane sulfur species and related modifications such as S-nitrosothiols. Access to this growing chemical toolbox of new molecular probes for H2S and related RSS sets the stage for applying these developing technologies to probe reactive sulfur biology in living systems.

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Chemical probes for molecular imaging and detection of hydrogen sulfide and reactive sulfur species in biological systems

Recently, the strategy of protection–deprotection of functional groups has been widely employed to design fluorescent probes, as the protection–deprotection of functional groups often induces a marked change in electronic properties. Significant advances have been made in the development of analyte-responsive fluorescent probes based on the protection–deprotection strategy. In this tutorial review, we highlight the representative examples of small-molecule based fluorescent probes for bioimaging, which are operated via the protection–deprotection of key functional groups such as aldehyde, hydroxyl, and amino functional groups reported from 2010 to 2014. The discussion includes the general protection–deprotection methods for aldehyde, hydroxyl, or amino groups, as well as the design strategies, sensing mechanisms, and deprotection modes of the representative fluorescent imaging probes applied to bio-imaging.

Development of fluorescent probes based on protection-deprotection of the key functional groups for biological imaging.

The ability to spatiotemporally identify the formation of specific anionic species, or track changes in their concentration inside living systems, is of critical importance in deciphering their exact biological roles and effects. The development of probes (also called bioimaging agents and intracellular sensors) to achieve this goal has become a rapidly growing branch of supramolecular chemistry. In this critical review the challenges specific to the task are identified and for a select range of small anions of environmental and biological relevance (fluoride, chloride, iodide, cyanide, pyrophosphate, bicarbonate, hydrosulphide, peroxynitrite, hypochlorite and hypobromite) a comprehensive overview of the currently available in vitro and in vivo probes is provided.

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Luminescent probes for the bioimaging of small anionic species in vitro and in vivo

A “turn-on” fluorescein-based probe for sulfite detection has been established employing SO 3 2− promoted levulinyl cleavage and concurrent generation of fluorescein. The synthesized probe exhibits high SO 3 2− selectivity over fourteen other anion ions, and the satisfactory detection limit was 0.80 mg/L in aqueous media containing co-solvent CH 3 CN (1%, v/v). The probe is successfully applied for the detection of sulfite in white wine.

A fluorescein-based probe with high selectivity and sensitivity for sulfite detection in aqueous solution

A "Turn-on" Fluorescent Hg2+ Chemosensor Based on Ferrier Carbocyclization

A “turn-on” fluorescence probe for Cu2+ detection has been reported according to a Cu2+ triggered spirolactam ring-opening reaction. The probe is a double-responsive fluorescent and colorimetric Cu2+-specific sensor in aqueous solution containing 20% of acetonitrile with high selectivity and excellent sensitivity (limit of detection is 12 μg L−1). Furthermore, the significant color changes visible to the naked eye at the concentration of 3 μM (ca. 0.20 mg L−1) are about ten times lower than the WHO (World Health Organization) recommended level (2.0 mg L−1) for Cu2+ ions in drinking water.

Solvent controlled sugar–rhodamine fluorescence sensor for Cu2+ detection

A carbohydrate modified fluoride ion sensor and its applications.

A “turn-on” sugar–rhodamine fluorescent probe for Cu2+ detection in CH3CN has been designed and synthesized according to a Cu2+ triggered spirolactam ring-opening reaction. The introduction of sugar into probe molecule, combining with solvent effect, significantly improved its selectivity and sensitivity. The synthesized probe exhibits high Cu2+ selectivity and excellent sensitivity (limit of detection is ca. 10 μg/L) in acetonitrile media. The limit of detection is about 200 times lower than the World Health Organization (WHO) recommended level (2.0 mg/L) for Cu2+ ions in drinking water.

Xing Ma

Papers

A fluorescein-based probe with high selectivity and sensitivity for sulfite detection in aqueous solution

A "Turn-on" Fluorescent Hg2+ Chemosensor Based on Ferrier Carbocyclization

Solvent controlled sugar–rhodamine fluorescence sensor for Cu2+ detection

A carbohydrate modified fluoride ion sensor and its applications.

A highly selective and sensitive sugar–rhodamine “turn-on” fluorescent sensor for divalent copper ion detection in acetonitrile