3-Aminobenzeneboronic Acid Functionalized MoS2 Quantum Dot as Fluorescent Nanoprobe for the Determination of o-Dihydroxybenzene

Advances on chalcogenide quantum dots-based sensors for environmental pollutants monitoring

Water contamination represents a significant ecological impact with global consequences, contributing to water scarcity worldwide. The presence of several pollutants, including heavy metals, pharmaceuticals, pesticides, and pathogens, in water resources underscores a pressing global concern, prompting the European Union (EU) to establish a Water Watch List to monitor the level of these substances. Nowadays, the standard methods used to detect and quantify these contaminants are mainly liquid or gas chromatography coupled with mass spectrometry (LC/GC-MS). While these methodologies offer precision and accuracy, they require expensive equipment and experienced technicians, and cannot be used on the field. In this context, chalcogenide quantum dots (QDs)-based sensors have emerged as promising, user-friendly, practical, and portable tools for environmental monitoring. QDs are semiconductor nanocrystals that possess excellent properties, and have demonstrated versatility across various sensor types, such as fluorescent, electrochemical, plasmonic, and colorimetric ones. This review summarizes recent advances (2019-2023) in the use of chalcogenide QDs for environmental sensing, highlighting the development of sensors capable of detect efficiently heavy metals, anions, pharmaceuticals, pesticides, endocrine disrupting compounds, organic dyes, toxic gases, nitroaromatics, and pathogens.

Fluorescent and Colorimetric Dual-signal Enantiomers Recognition via Enzyme Catalysis: The Case of Glucose Enantiomers Using Nitrogen-doped Silicon Quantum Dots/Silver Probe Coupled with β-D-Glucose Oxidase

Chiral enantiomer recognition is important but facing tough challenges in the direct quantitative determination for complex samples. In this work, via chosing nitrogen-doped silicon quantum dots (N-SiQD) as optical nanoprobe and constructing N-SiQD/silver (N-SiQD/Ag NPs) complex, β-D-GOx as model enzyme and glucose enantiomers as analytes, a fluorescent and colorimetric dual-signal chiral sensing strategy was proposed herein for chiral recognition based on specific enzyme-catalyzed reaction. N-SiQD can exhibit intense fluorescence, while it can be quenched by Ag NPs owing to the formation of N-SiQD/Ag NPs. In the presence of glucose isomer, D-glucose is catalytically hydrolyzed by β-D-GOx to form H₂O₂ owing to the specific enzyme catalyzed reaction between D-glucose and β-D-GOx, and H₂O₂ can etch Ag NPs from the N-SiQD/Ag NPs probe to change the solution color from brown to colorless and restore the N-SiQD fluorescence; while these phenomena cannot be caused by L-glucose, a dual-signal sensing method was thus constructed for recognizing glucose enantiomers. It is believed that the chiral enantiomers recognition strategy via enzyme catalysis has great application for selective and quantificational detection of enantiomers in the complex sample system.