A boric acid-functionalized lanthanide metal-organic gel: A ratiometric fluorescence probe with rapid and sensitive detection of dopamine

An Encyclopedic Compendium on Chemosensing Supramolecular Metal-Organic Gels

Chemosensing, an interdisciplinary scientific domain, plays a pivotal role ranging from environmental monitoring to healthcare diagnostics and (inter)national security. Metal-organic gels (MOGs) are recognized for their stability, selectivity, and responsiveness, making them valuable for chemosensing applications. Researchers have explored the development of MOGs based on different metal ions and ligands, allowing for tailored properties and sensitivities, and have even demonstrated their applications as portable sensors such as paper-based test strips for practical use. Herein, several studies related to MOGs development and their applications in the chemosensing field via UV-visible or luminance along with electrochemical approach are presented. These papers explored MOGs as versatile materials with their use in sensing bio or environmental analytes. This review provides a foundational understanding of key concepts, methodologies, and recent advancements in this field, fostering the scientific community.

Gold Nanocluster-Encapsulated Hyperbranched Polyethyleneimine for Selective and Ratiometric Dopamine Analyses by Enhanced Self-Polymerization

The exploitation of selective and sensitive dopamine (DA) sensors is essential to more deeply understand its biological function and diagnosis of related diseases. In this study, gold nanocluster-encapsulated hyperbranched polyethyleneimine (hPEI-Au NCs) has been explored as the specific and ratiometric DA nanoprobe through hPEI-assisted DA self-polymerization reactions. The Au NCs encapsulation not only provides a fluorescent internal reference but also enhances the DA self-polymerization by weakening the proton sponge effect of the hPEI layer. Rapid and sensitive DA detection is realized through the proposed hPEI-Au NC nanoprobe with a limit of detection of 10 nM. The favorable selectivity over other possible interferents including amino acids, sugars, and salts is due to the specific self-polymerization reaction. The DA analysis in urine samples with small relative standard deviations has been accomplished with an hPEI-Au NC nanoprobe.

A gel fluorescence sensor based on CDs@SiO2/FeS2@MIPs for the visual detection of p-chlorophenol

There is a critical need for the rapid detection of p-chlorophenol produced by pesticide abuse and industrial wastewater discharge, which has been an urgent problem in the realm of environmental protection. Here, a green and environmentally friendly method was developed to prepare stable and low toxicity quantum dots. First, blue-green fluorescent FeS₂ quantum dots (B-FeS₂ QDs) were prepared with FeCl₃·6H₂O (an iron source) and L-cysteine (a capping agent) by the solvothermal method. By combining B-FeS₂ QDs with orange carbon dots (O-CDs), a CDs@SiO₂/FeS₂@MIPs visual fluorescence sensor for the selective detection of p-chlorophenol was constructed. Under optimum conditions, this sensor exhibited a detection limit of 1.265 μM with a linear range of 5.00-50.00 μM and was successfully applied to detect p-chlorophenol in real samples. Moreover, this sensor was successfully applied to visual semi-quantitative detection of p-chlorophenol. This work demonstrated that these sensors, based on FeS₂ QDs and CDs, had potentials for in situ and visual detection of environmental contaminants.

Bimetallic Cd/Zr-UiO-66 material as a turn-on/off probe for As5+/Fe3+ in organic media

In this work, a series of bimetallic Cd/Zr-UiO-66 materials were successfully synthesized for fluorescence sensing toward traces of As⁵⁺ and Fe³⁺ via a one-pot method. Interestingly, the obtained bimetallic Cd/Zr-UiO-66 (1:9) can be served as turn-on probe for As⁵⁺ as well as turn-off probe for Fe³⁺. The LODs of Cd/Zr-UiO-66 (1:9) toward As⁵⁺ and Fe³⁺ were calculated to be 5.4 μM and 4.3 μM, respectively, indicating its effective sensing properties for As⁵⁺ and Fe³⁺ in methanol media. Moreover, even in the presence of other potentially interfering toxic metal ions such as As³⁺, Cd²⁺ and Pb²⁺, Cd/Zr-UiO-66 (1:9) still presented good anti-interference abilities. Additionally, the removal efficiency of Cd/Zr-UiO-66 (1:9) toward As⁵⁺ was higher than 70% when the initial As⁵⁺ was lower than 50 mg/L. The fluorescence quenching of Fe³⁺ were mainly due to the competitive absorption of excitation source and RET, while the ACE mechanism was mostly responsible for the enhancement of As⁵⁺. More importantly, this job might pave the way for future researches and applications on sensing As⁵⁺ and Fe³⁺.

The controllable synthesis of orange-red emissive Au nanoclusters and their use as a portable colorimetric fluorometric probe for dopamine

The fabrication of orange-red emissive M-AuNCs and their utility in the detection of dopamine assisted by a smartphone.