High quantum yield nitrogen and boron co-doped carbon dots for sensing Ag+, biological imaging and fluorescent inks

The utilization of quantum dot labeling as a burgeoning technique in the field of biological imaging

Quantum dots (QDs), with their unique optical and physical properties, have revolutionized the field of biological imaging, providing researchers with tools to explore cellular processes and molecular interactions in unprecedented detail. This review explores the diverse properties of QDs, emphasizing their application in biological imaging and addressing both their advantages and challenges. We discuss the developments in QD technology that have facilitated their integration into bioimaging, highlighting the role of surface modifications in enhancing their biocompatibility and functionality. The varied applications of QDs in both in vitro and in vivo imaging settings are examined, showcasing their capacity to deliver brighter, more stable, and multiplexed imaging solutions compared to traditional fluorescent dyes. Furthermore, we delve into the challenges associated with QD use, particularly concerns regarding their potential toxicity and long-term effects on biological systems, and explore ongoing research aimed at mitigating these issues. Finally, we discuss future directions in QD technology, anticipating advancements that will further solidify their role in biological imaging and open up new avenues for scientific exploration.

One-step synthesis of N, S-doped carbon dots with green emission and their application in 4-NP detection, pH sensing, and cell imaging

Using p-aminophenol and dithioacetamide as precursors, green luminescent nitrogen (N) and sulfur (S) co-doped carbon dots (N, S-CDs) are prepared by hydrothermal method with the quantum yield (QY) of 7.1 %. Superior properties of the N, S-CDs including high photostability, outstanding biocompatibility, and desirable biological penetration were found, which could realize the monitor of 4-nitrophenol (4-NP) and pH. The N, S-CDs can be designed as a fluorescent probe for sensitive detection of 4-NP in water samples with linear ranges of 0-85 µM and a detection limit of 0.037 µM. Moreover, the fluorescence intensity of N, S-CDs is sensitive to pH and shows a linear relationship with pH values ranging from 3.50 to 7.25 and 7.25-12.00, accompanied with a significant color variation of the N, S-CDs solution from colorless to brown. Finally, the proposed N, S-CDs have also been applied to monitor the 4-NP in oocysts due to its low cytotoxicity, providing a great capacity for various targets molecules detection.

Carbon Dots-Based Fluorescence Assay for the Facile and Reliable Detection of Ag+ in Natural Water and Serum Samples

In this report, red-emissive carbon dots (C-dots) were facilely prepared from o-phenylenediamine via microwave-assisted hydrothermal treatment. The C-dots demonstrated excitation wavelength-independent emission with maximums at 621 nm that could be effectively quenched by Ag⁺ via static quenching. This phenomenon was exploited to establish a sensitive fluorescence assay with a low detection limit (0.37 μM) and wide linear range (0-50 μM). In addition, this assay demonstrated excellent selectivity toward Ag⁺, free from the interference of 16 commonly seen metal ions. Most importantly, the assay demonstrated high reliability toward samples in deionized water, mineral water, lake water, and serum, which could indicate potential applications for Ag⁺ monitoring in complicated natural and biological environments.