The enantiomers of chiral amino acids play versatile roles in biological systems including humans. They are also very useful in the asymmetric synthesis of diverse chiral organic compounds. Therefore, identifying a specific amino acid and distinguishing it from its enantiomer are of great importance. Although significant progress has been made in the development of fluorescent probes for amino acids, most of them are not capable of conducting simultaneous chemoselective and enantioselective detection of a specific amino acid enantiomer. In this article, several fluorescent probes have been designed and synthesized for chemoselective as well as enantioselective recognition of certain amino acid enantiomers. ( S )-1 shows greatly enhanced fluorescence in the presence of l -glutamic acid and l -aspartic acid, but produces no or little fluorescence response toward their opposite enantiomers and other amino acids. ( R )-4 in combination with Zn 2+ shows greatly enhanced fluorescence in the presence of l -serine. ( S )-6 is designed for the selective recognition of histidine. Micelles made of an amphiphilic diblock copolymer are used to encapsulate the water-insoluble compound ( S )-8 which shows chemoselective as well as enantioselective fluorescence enhancement with l -lysine in the presence of Zn 2+ in aqueous solution. The same micelles are also used to encapsulate several ( S )-1,1′-binaphthyl-based monoaldehydes ( S )-10 for the chemoselective and enantioselective fluorescence recognition of l -tryptophan in the presence of Zn 2+ in aqueous solution. These findings have demonstrated that highly selective fluorescence identification of a specific amino acid enantiomer can be achieved by incorporating certain functional groups at the designated locations of the 1,1′-binaphthyls. The binaphthyl core structure of these probes provides both a chirality source and highly tunable fluorescence properties. Matching the structure and chirality of these probes with those of the specific amino acid enantiomers can generate structurally rigid reaction products and give rise to greatly enhanced fluorescence. The strategies of this work can be further expanded to develop fluorescent probes for the specific identification of many amino acids of interest. This should facilitate the analysis of chiral amino acids in various applications. The outlook of this research and its comparison with other methods are also discussed.
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Detection Technologies for Reactive Oxygen Species: Fluorescence and Electrochemical Methods and Their Applications
Reactive oxygen species (ROS) have been found in plants, mammals, and natural environmental processes. The presence of ROS in mammals has been linked to the development of severe diseases, such as diabetes, cancer, tumors, and several neurodegenerative conditions. The most common ROS involved in human health are superoxide (O2•−), hydrogen peroxide (H2O2), and hydroxyl radicals (•OH). Organic and inorganic molecules have been integrated with various methods to detect and monitor ROS for understanding the effect of their presence and concentration on diseases caused by oxidative stress. Among several techniques, fluorescence and electrochemical methods have been recently developed and employed for the detection of ROS. This literature review intends to critically discuss the development of these techniques to date, as well as their application for in vitro and in vivo ROS detection regarding free-radical-related diseases. Moreover, important insights into and further steps for using fluorescence and electrochemical methods in the detection of ROS are presented.
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- Award ID(s):
- 1817294
- NSF-PAR ID:
- 10230828
- Date Published:
- Journal Name:
- Biosensors
- Volume:
- 11
- Issue:
- 2
- ISSN:
- 2079-6374
- Page Range / eLocation ID:
- 30
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3390/bios11020030
