Excitation-depended fluorescence emission of boron-doped graphene quantum dot as an optical probe for detection of oxytetracycline in food and information encryption patterns

Monitoring of trace oxytetracycline using a porphyrin-MOF layer-based electrochemical aptasensor

A two-dimensional porphyrin-MOF nanolayer was developed to construct an electrochemical aptasensor for monitoring oxytetracycline from 0.01 pg mL-1 to 0.1 ng mL-1. This aptasensor exhibited high sensitivity, outstanding selectivity, good stability, fine reproducibility, and quantitative detection ability in real samples.

A dual-response ratiometric fluorescent sensor for oxytetracycline determination in milk and mutton samples

Owing to the adverse effects of oxytetracycline (OTC) residues on human health, it is of great importance to construct a rapid and effective strategy for OTC detection. Herein, we developed a dual-response fluorescence sensing platform based on molybdenum sulfide quantum dots (MoS2 QDs) and europium ions (Eu3+) for ratiometric detection of OTC. The MoS2 QDs, synthesized through an uncomplicated one-step hydrothermal approach, upon OTC integration into the MoS2 QDs/Eu3+ sensing system, exhibit a significant quenching of blue fluorescence due to the inner filter effect (IFE), simultaneously enhancing the distinct red emission of Eu3+ at 624 nm, a phenomenon attributed to the antenna effect (AE). This sensor demonstrates exceptional selectivity and sensitivity towards OTC, characterized by a linear detection range of 0.2-10 μM and a notably low detection limit of 2.21 nM. Furthermore, we achieved a visual semi-quantitative assessment of OTC through the discernible fluorescence color transition from blue to red under a 365 nm ultraviolet lamp. The practical applicability of this sensor was validated through the successful detection of OTC in milk and mutton samples, underscoring its potential as a robust tool for OTC monitoring in foodstuffs to safeguard food safety.

Amphiphilic Polyurethane with Cluster-Induced Emission for Multichannel Bioimaging in Living Cell Systems

The development of single-component materials with low cytotoxicity and multichannel fluorescence imaging capability is a research hotspot. In the present work, highly electron-deficient pyrazine monomers were covalently connected into a polyurethane backbone using addition polymerization with terminal poly(ethylene glycol) monomethyl ether units containing a high density of electron pairs. Thereby, an amphiphilic polyurethane-pyrazine (PUP) derivative has been synthesized. The polymer displays cluster-induced emission through compact inter- and/or intramolecular noncovalent interactions and extensive through-space electron coupling and delocalization. Molecular rigidity facilitates red-shifted emission. Based on hydrophilic/hydrophobic interactions and excitation dependence emission at low concentrations, PUP has been self-assembled into fluorescent nanoparticles (PUP NPs) without additional surfactant. PUP NPs have been used for cellular multicolor imaging to provide a variety of switchable colors on demand. This work provides a simple molecular design for environmentally sustainable, luminescent materials with excellent photophysical properties, biocompatibility, low cytotoxicity, and color modulation.

Recent Advancements in Metal and Non-Metal Mixed-Doped Carbon Quantum Dots: Synthesis and Emerging Potential Applications

In nanotechnology, the synthesis of carbon quantum dots (CQDs) by mixed doping with metals and non-metals has emerged as an appealing path of investigation. This review offers comprehensive insights into the synthesis, properties, and emerging applications of mixed-doped CQDs, underlining their potential for revolutionary advancements in chemical sensing, biosensing, bioimaging, and, thereby, contributing to advancements in diagnostics, therapeutics, and the under standing of complex biological processes. This synergistic combination enhances their sensitivity and selectivity towards specific chemical analytes. The resulting CQDs exhibit remarkable fluorescence properties that can be involved in precise chemical sensing applications. These metal-modified CQDs show their ability in the selective and sensitive detection from Hg to Fe and Mn ions. By influencing their exceptional fluorescence properties, they enable precise detection and monitoring of biomolecules, such as uric acid, cholesterol, and many antibiotics. Moreover, when it comes to bioimaging, these doped CQDs show unique behavior towards detecting cell lines. Their ability to emit light across a wide spectrum enables high-resolution imaging with minimal background noise. We uncover their potential in visualizing different cancer cell lines, offering valuable insights into cancer research and diagnostics. In conclusion, the synthesis of mixed-doped CQDs opens the way for revolutionary advancements in chemical sensing, biosensing, and bioimaging. As we investigate deeper into this field, we unlock new possibilities for diagnostics, therapeutics, and understanding complex biological processes.