Terbium (III)-based Metallacrowns with aggregation-induced emission feature coupled with cu (II) for fluorescence detection of cysteine

The Metallacrowns (MCs) composed of repeated [Metal-N-O] subunits are a type of new material, but the MCs have not been developed and utilized in analytical applications. This essay reports on a new kind of terbium(III)-based Metallacrowns (Tb-MCs) with aggregation-induced emission (AIE) feature to build a sensing platform. It is first time that Tb-MCs are able to aggregate to larger aggregates in water along with a bright green emission, so that the property makes it possible to apply in biosensing. Thereafter, the AIE of Tb-MCs can be quenched effectively by Cu²⁺. Based on the high affinity of thiol to Cu²⁺, cysteine (Cys) recovers the fluorescence of Tb-MCs in the presence of Cu²⁺. There is a good linear range varying from 0.02 to 20 μM with a low limit of detection (LOD) 9.67 nM of Cys. In the end, this novel probe is also successfully applied to the determination of Cys in human serum with satisfactory results.

A novel l-cysteine sensor using in-situ electropolymerization of l-cysteine: Potential to simple and selective detection

This work presents an all-in-one origami paper-based electrochemical platform for simple and inexpensive l-cysteine (Cys) detection using Cys as a monomer for modifying electrode surfaces. The proposed method combines the steps of electropolymerization and detection into a single device to offer a highly convenient method for the end-user. In comparison, the sensitivity toward Cys detection is a significantly increased using this modified electrode. The developed device provided a linear concentration range of 10-800 μM with a limit of detection of 5.5 μM. For application, the device was successfully applied to detect Cys in different food products such as wheat flour, bread, and cake with satisfactory results, yielding excellent intra-day and inter-day relative standard deviations (1.5-4.9%) and recoveries (84.2-110.8%). This discovery is important from the viewpoint of the development of Cys detection in other applications in the future.

A novel and cost effective isatin based Schiff base fluorophore: a highly efficient “turn-off” fluorescence sensor for the selective detection of cysteine in an aqueous medium

We designed an efficient, sensitive, and selective chemosensor for the fluorimetric determination of cysteine.

An anthraquinone-imidazole-based colorimetric and fluorescent sensor for the sequential detection of Ag+ and biothiols in living cells

An anthraquinone-imidazole-based highly selective colorimetric and fluorescent sensor for the sequential detection of Ag⁺ and biothiols in living cells is reported.

Silver-ion-mediated Mg2+-dependent DNAzyme activity for amplified fluorescence detection of cysteine

Schematic illustration of a DNAzyme-based fluorescent biosensor for amplified Cys detection.

Conventional and Mechanochemical Syntheses of Copper(I) Iodide Luminescent MOF with Bis(amidoquinoline) and Its Application for the Detection of Amino Acid in Aqueous Solution

Formation of a copper(I) iodide cluster based luminescent metal-organic frameworks (LMOFs) and its utilization for the detection of cysteine (Cys) in aqueous solution are reported. The reaction of bis(amidoquinoline) ligand (L) with copper(I) iodide afforded an LMOF {[(Cu₂I₂)L₂]·2DMSO} _n (1) with a 4⁴-sql topology linked by Cu₂I₂ clusters as a thermodynamic product. Time- and temperature-dependent PXRD experiments confirmed that the entire formation process for 1 is kinetically and thermodynamically controlled. Interestingly, LMOF 1 was also obtained under the mechanochemical condition. Moreover, LMOF 1 dispersed in water shows a selective quenching for Cys over other amino acids due to the strong affinity of Cys to copper(I) iodide. On the basis of the NMR data of L isolated from the decomposition of 1, the decomposition-displacement mechanism was proposed for the sensing of Cys. This result might be utilized for the practical detection of Cys because the sensing material can be prepared simply, and the sensing process is performed in aqueous media.