Fluorescent/Colorimetric Dual-Mode Discriminating Gln and Val Enantiomers Based on Carbon Dots

Abstract

Discrimination and quantification of amino acid (AA) enantiomers are particularly important for diagnosing and treating diseases. Recently, dual-mode probes have gained a lot of research interest because they can catch more detecting information compared with the single-mode probes. Thus, it is of great significance to develop a dual-mode sensor realizing AA enantiomer discrimination conveniently and efficiently. In this work, carbon dot L-TCDs were prepared by N-methyl-1,2benzenediamine dihydrochloride (OTD) and L-tryptophan. With the assistance of H 2 O 2 , L-TCDs show an excellent discrimination performance for enantiomers of glutamine (Gln) and valine (Val) in both fluorescent and colorimetric modes. The fluorescence enantioselectivity of Gln (F D /F L ) and Val (F L /F D ) is 5.29 and 4.13, respectively, and the colorimetric enantioselectivity of Gln (I D /I L ) and Val (I L /I D ) is 13.26 and 3.42, individually. The chiral recognition mechanism of L-TCDs was systematically studied. L-TCDs can be etched by H 2 O 2 , and the participation of AA enantiomers results in different amounts of the released OTD, which provides fluorescent and colorimetric signals for identifying and quantifying the enantiomers of Gln and Val. This work provides a more convenient and flexible dual-mode sensing strategy for discriminating AA enantiomers, which is expected to be of great value in facile and high-throughput chiral recognition.

Preparation of D-NCCDs and its application in fluorescent/colorimetric dual-mode discrimination of glutamine enantiomers

“…After the addition of H 2 O 2 , the average particle size of D-NCCDs decreases from 2.2 nm to 1.1 nm, and then after the addition of L-Gln and D-Gln, the average particle size is 1.1 nm and 3.3 nm, respectively. The strong oxidation of H 2 O 2 will reduce the particle size of D-NCCDs after etching, and the addition of Gln enantiomers will affect the nal particle size of D-NCCDs after reaction with H 2 O 2 [22,38]. The results showed that the addition of L-Gln did not affect the interaction between D-NCCDs and H 2 O 2 .…”

“…Zor et al developed a simple, universal, and disposable colorimetric sensing platform utilizing nano-paper and AgNPs, enabling the visual chiral recognition of cysteine enantiomers [20]. However, compared to the limitations of single-mode detection methods, uorescent/colorimetric dual-mode sensors that can simultaneously provide high sensitivity uorescence and visible color signals are receiving increasing attention [21,22]. The combination of uorescence and colorimetric modes ensures the accuracy and reliability of detection results.…”

Carbon Dots in Enantioselective Sensing

“…Ren, Zhang and colleagues ( Table 1 , entry 1 [ 33 ]) reported a dual-mode, fluorescence/colorimetric sensor using carbon dots (TCDs) synthesized from N -methyl-1,2-benzene diamine dihydrochloride (OTD) and L-tryptophan (L-Trp) as a chiral agent by a hydrothermal method. The chirality of starting tryptophan was maintained in the CDs, as demonstrated by circular dichroism.…”

Hydrogen Bonding-Induced Aggregation of Chiral Functionalized AuNS@Ag NPs for Photothermal Enantioanalysis

“…Chiral chemosensors represent an advanced analytical strategy wherein a chiral host exhibits selective binding toward one guest enantiomer over its counterpart. , Nowadays, various sensing strategies for enantiomers have been developed, including encompassing colorimetry, , fluorescence, ,− electrochemistry, − and so on. Among all available strategies, temperature sensing has begun to emerge as a promising approach of chiral analysis due to its numerous advantages, including fast response, high reproducibility, and minimal background signal. , The conventional response principle of chiral sensors based on the photothermal effect involves the enantioselective adsorption of target molecules on photothermal materials, resulting in differential changes in their photothermal conversion properties. − Nevertheless, altering the inherent photothermal properties of photothermal materials through the chemical interactions of target molecules is challenging, and this adsorption process cannot avoid nonspecific physical adsorption .…”