Nano-hybrid luminophores of Ti3C2TX quantum dots-gold nanoparticles based on in situ generation for sensitive electrochemiluminescence biosensing

Titanium Carbide (Ti3C2Tx) MXene for Sequestration of Aquatic Pollutants

The rapid expansion of industrialization has resulted in the release of multiple ecological contaminants in gaseous, liquid, and solid forms, which pose significant environmental risks to many different ecosystems. The efficient and cost-effective removal of these environmental pollutants has attracted global attention. This growing concern has prompted the synthesis and optimization of nanomaterials and their application as potential pollutant removal. In this context, MXene is considered an outstanding photocatalytic candidate due to its unique physicochemical and mechanical properties, which include high specific surface area, physiological compatibility, and robust electrodynamics. This review highlights recent advances in shaping titanium carbide (Ti3C2Tx) MXenes, emphasizing the importance of termination groups to boost photoactivity and product selectivity, with a primary focus on engineering aspects. First, a broad overview of Ti3C2Tx MXene is provided, delving into its catalytic properties and the formation of surface termination groups to establish a comprehensive understanding of its fundamental catalytic structure. Subsequently, the effects of engineering the morphology of Ti3C2Tx MXene into different structures, such as two-dimensional (2D) accordion-like forms, monolayers, hierarchies, quantum dots, and nanotubes. Finally, a concise overview of the removal of different environmental pollutants is presented, and the forthcoming challenges, along with their prospective outlooks, are delineated.

An electrochemiluminescence aptasensor based on Ti3C2 QDs-1T/2H MoS2 nano-hybrid material for the highly sensitive detection of lincomycin

Developing a highly selective and sensitive analysis strategy for lincomycin (LIN) is of great significance for environmental protection and food safety. Herein, we reported a novel electrochemiluminescence (ECL) aptasensor based on Ti3C2 QDs-1T/2H MoS2 nano-hybrid luminophore for detection of LIN. The hybridization of Ti3C2 QDs and 1T/2H MoS2 endowed nanocomposite with structural and compositional advantages for boosting the ECL performance of QDs by about three times. This enhancement could be attributed to the remarkable electrocatalytic activity and high conductivity exhibited by 1T/2H MoS2. Secondly, the great surface area of 1T/2H MoS2 is conducive to the high dispersion of Ti3C2 QDs, and its good conductivity could promote charge transfer. On the other hand, the excellent catalytic performance of 1T/2H MoS2 could facilitate the reduction of S2O82- to produce more radical, which significantly enhance the ECL signal of Ti3C2 QDs. Given these features, a sensor for detection of LIN was established based on specific recognition between target and aptamer. The sensor showed a good linear relationship (0.05 ng mL-1 ∼100 μg mL-1) with a detection limit as low as 0.02 ng mL-1. It is worth noting that this work has been validated in testing milk samples, exhibiting great potential application prospects in food analysis.

Simple and sensitive fluorescence sensing of methyl parathion based on the inner filter effect of p-nitrophenol on nitrogen-doped titanium carbide quantum dots

It is of great significance to develop an effective method for methyl parathion (MP) detection. Herein, a novel nitrogen-doped titanium carbide quantum dots (N-Ti3 C2 QDs) was prepared and used to construct a simple and sensitive fluorescence sensing platform of MP by making use of inner filter effect (IFE). The prepared N-Ti3 C2 QDs can exhibit strong blue fluorescence at 434 nm. Meanwhile, MP could hydrolyze to produce p-nitrophenol (p-NP) under alkaline conditions, which showed a characteristic ultraviolet-visible (UV-visible) absorption peak at 405 nm, resulting in the fluorescence of N-Ti3 C2 QDs is effectively quenched by p-NP. In addition, the investigation of time-resolved fluorescence decays indicated that the corresponding quenching mechanism of p-NP on N-Ti3 C2 QDs is due to the IFE. After optimizing the conditions, the as-developed fluorescence sensing platform displayed wide detection range (0.1-30 μg mL-1 ) and low detection limit (0.036 μg mL-1 ) for MP, and it was also successfully applied for MP analysis in real water samples, thus it is expected that this simple, sensitive and enzyme-free sensing platform shows great applications.

Advanced growth of 2D MXene for electrochemical sensors

Over the last few years, electroanalysis has made significant advancements, particularly in developing electrochemical sensors. Electrochemical sensors generally include emerging Photoelectrochemical and Electrochemiluminescence sensors, which combine optical techniques and traditional electrochemical bio/non-biosensors. Numerous EC-detecting methods have also been designed for commercial applications to detect biological and non-biological markers for various diseases. Analytical applications have recently focused significantly on one of the novel nanomaterials, the MXene. This material is being extensively investigated for applications in electrochemical sensors due to its unique mechanical, electronic, optical, active functional groups and thermal characteristics. This study extensively discusses the salient features of MXene-based electrochemical sensors, photoelectrochemical sensors, enzyme-based biosensors, immunosensors, aptasensors, electrochemiluminescence sensors, and electrochemical non-biosensors. In addition, their performance in detecting various substances and contaminants is thoroughly discussed. Furthermore, the challenges and prospects the MXene-based electrochemical sensors are elaborated.

High-Intensity Focused Ultrasound Combined with Ti3C2-TiO2 to Enhance Electrochemiluminescence of Luminol for the Sensitive Detection of Polynucleotide Kinase

Luminol is a classic electrochemiluminescence (ECL) luminophore. The luminol-O₂ ECL system suffers from a problem, that is, the conversion rate of dissolved O₂ into reactive oxygen species (ROS) is low. In this work, we used high-intensity focused ultrasound (HIFU) pretreatment combined with Ti₃C₂-TiO₂ to construct a highly sensitive luminol-O₂ ECL system for the specific detection of polynucleotide kinase (PNK) first. On the one hand, HIFU generated ROS in situ as a coreactant via the cavitation effect to boost the luminol emission. On the other hand, Ti₃C₂-TiO₂ was prepared in situ via Ti₃C₂ as a reducing agent, and it can aggregate and catalyze ROS generated in situ by HIFU. Moreover, the Ti on the Ti₃C₂-TiO₂ surface could bind to phosphate groups through chelation, thereby realizing highly specific detection of PNK. The sensor has a linear relationship range of 1.0 × 10^-5 to 10.0 U mL^-1, and the limit of detection is 1.48 × 10^-7 U mL^-1, which is superior to most existing methods. The sensor performance in HeLa cell lysate was measured with a satisfactory result. The designed ECL biosensor has potential applications in biological analysis and clinical diagnosis.

Boosting the electrochemiluminescence of luminol-O2 system by high-intensity focused ultrasound

Electrochemiluminescence (ECL) of luminol is a well-established methodology in analytical chemistry and bioimaging. Developing novel strategies to enhance the ECL signal of this model emitter is a challenging but rewarding task. In this work, we introduced the high-intensity focused ultrasound (HIFU), as a pretreatment means and a non-invasive way to trigger and boost the ECL signal with a 40-fold significant enhancement in the luminol-O₂ system without the addition of exogenous co-reactants. The superoxide anion (O₂^-•) generated in situ by HIFU was the key initiator for boosting the ECL emission as demonstrated in this study for the first time. This promising co-reactant-free strategy could find potential applications for ultrasensitive ECL detection in the analysis of complex biological entities.