Herein, a sensitive and selective sensor for biothiols based on the recovered fluorescence of the CdTe quantum dots (QDs)-Hg(II) system is reported. Fluorescence of QDs could be quenched greatly by Hg(II). In the presence of biothiols, such as glutathione (GSH), homocysteine (Hcy), and cysteine (Cys), however, Hg(II) preferred to react with them to form the Hg(II)-S bond because of the strong affinity with the thiols of biothiols rather than quenching the fluorescence of the QDs. Thus, the fluorescence of CdTe QDs was recovered. The restoration ability followed the order GSH > Hcy > Cys due to the decreased steric hindrance effect. A good linear relationship was obtained from 0.6 to 20.0 micromol L(-1) for GSH and from 2.0 to 20.0 micromol L(-1) for Cys, respectively. The detection limits of GSH and Cys were 0.1 and 0.6 micromol L(-1), respectively. In addition, the method showed a high selectivity for Cys among the other 19 amino acids. Furthermore, it succeeded in detecting biothiols in the Hela cell.

Sensitive and Selective Sensor for Biothiols in the Cell Based on the Recovered Fluorescence of the CdTe Quantum Dots−Hg(II) System

The incorporation of biomolecules into nanomaterials generates functional nanosystems with novel and advanced properties, presenting great potential for applications in various fields. Nucleobases, nucleosides and nucleotides, as building blocks of nucleic acids and biological coenzymes, constitute necessary components of the foundation of life. In recent years, as versatile biomolecules for the construction or regulation of functional nanomaterials, they have stimulated interest in researchers, due to their unique properties such as structural diversity, multiplex binding sites, self-assembly ability, stability, biocompatibility, and chirality. In this review, strategies for the synthesis of nanomaterials and the regulation of their morphologies and functions using nucleobases, nucleosides, and nucleotides as building blocks, templates or modulators are summarized alongside selected applications. The diverse applications range from sensing, bioimaging, and drug delivery to mimicking light-harvesting antenna, the construction of logic gates, and beyond. Furthermore, some perspectives and challenges in this emerging field are proposed. This review is directed toward the broader scientific community interested in biomolecule-based functional nanomaterials.

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Nucleobases, nucleosides, and nucleotides: versatile biomolecules for generating functional nanomaterials

Fluorescent signal-based lateral flow immunochromatographic strips (FLFICS) have received great expectations since they effectively improve detection sensitivity with quantitative analysis, and still retain the advantages of simplicity, rapidness, and portability of a common lateral flow immunochromatographic strip (LFICS) Diverse fluorescent reporters have promoted development of FLFICS, such as fluorescent dyes, quantum dots (QDs), an up-converting phosphor (UCP), lanthanide labels, and other fluorescence nanoparticles In this work, we discuss the different fluorescent reporters applied with LFICS and their unique properties as well as signal amplification strategies helping to enhance detection performance Benefitting from these sensitive and accurate fluorescent labels, FLFICS commendably satisfies requirements for detecting different disease biomarkers in medical diagnosis, strict supervision of food safety, and water pollution This work also gives a short introduction to trends in the development of future FLFICS technology

A review of fluorescent signal-based lateral flow immunochromatographic strips.

Fluorescent/luminescent detection of natural amino acids by organometallic systems

A simple and sensitive method for L-cysteine detection based on the fluorescence intensity increment of quantum dots.

We present a novel method for the selective detection of cysteine, a sulfur-containing amino acid, which plays a crucial role in many important biological functions such as protein folding. Surface-modified colloidal CdS nanoparticles have been used as a fluorescent probe to selectively detect cysteine in the presence of other amino acids in the micromolar concentration range. Cysteine quenches the emission of CdS in the 0.5?10??M concentration range, whereas the other amino acids do not affect its emission. Among the other amino acids, histidine is most efficient in quenching the emission of the CdS nanoparticles. The sulfur atom of cysteine plays a crucial role in the quenching process in the 0.5?10??M concentration range. Cysteine is believed to quench the emission of the CdS nanoparticles by binding to their surface via its negatively charged sulfur atom. This method can potentially be applied for its detection in biological samples.

https://iopscience.iop.org/article/10.1088/0957-4484/19/46/465503/pdf

T. Inakhunbi Chanu

Papers

Surface-modified CdS nanoparticles as a fluorescent probe for the selective detection of cysteine.

Synthesis of histidine-stabilized cadmium sulfide quantum dots: Study of their fluorescence behaviour in the presence of adenine and guanine

Photophysical and photocatalytic properties of histidine-stabilized CdS quantum dots in the presence of indole