Fluorescent CDs@PCL hybrids via tartaric acid, CDs-cocatalyzed polymerization

Unlocking the Potential of Carbon Quantum Dots for Cell Imaging, Intracellular Localization, and Gene Expression Control in Arabidopsis thaliana (L.) Heynh

Utilizing carbon quantum dots (CQDs) as biomaterials for delivering small substances has gained significant attention in recent research. However, the interactions and mechanisms of action of CQDs on plants have received relatively little focus. Herein, we investigated the transportation of CQDs into various organs of Arabidopsis thaliana (L.) Heynh. via the vessel system, leading to the epigenetic inheritance of Argonaute family genes. Our findings reveal that CQDs may interact with microRNAs (miRNAs), leading to the repression of post-transcriptional regulation of target genes in the cytoplasm. Transcriptome and quantitative PCR analyses demonstrated consistent gene expression levels in offspring. Moreover, microscopic observations illustrated rapid CQD localization on cell membranes and nuclei, with increased nuclear entry at higher concentrations. Notably, our study identified an alternative regulatory microRNA, microRNA172D, for the Argonaute family genes through methylation analysis, shedding light on the connection between CQDs and microRNAs.

Design of Fluorescent Hybrid Materials Based on POSS for Sensing Applications

Polyhedral oligomeric silsesquioxane (POSS) has a nanoscale silicon core and eight organic functional groups on the surface, with sizes from 0.7 to 1.5 nm. The three-dimensional nanostructures of POSS can be used to build all types of hybrid materials with specific performance and controllable nanostructures. The applications of POSS-based fluorescent materials have spread across various fields. In particular, the employment of POSS-based fluorescent materials in sensing application can achieve high sensitivity, selectivity, and stability. As a result, POSS-based fluorescent materials are attracting increasing attention due to their fascinating vistas, including unique structural features, easy fabrication, and tunable optical properties by molecular design. Here, we summarize the current available POSS-based fluorescent materials from design to sensing applications. In the design section, we introduce synthetic strategies and structures of the functionalized POSS-based fluorescent materials, as well as photophysical properties. In the application section, the typical POSS-based fluorescent materials used for the detection of various target objects are summarized with selected examples to elaborate on their wide applications.

The Rapid and Large-Scale Production of Carbon Quantum Dots and their Integration with Polymers

Carbon quantum dots (CDs) have inspired vast interest because of their excellent photoluminescence (PL) performances and their promising applications in optoelectronic, biomedical, and sensing fields. The development of effective approaches for the large-scale production of CDs may greatly promote the further advancement of their practical applications. In this Minireview, the newly emerging methods for the large-scale production of CDs are summarized, such as microwave, ultrasonic, plasma, magnetic hyperthermia, and microfluidic techniques. The use of the available strategies for constructing CD/polymer composites with intriguing solid-state PL is then described. Particularly, the multiple roles of CDs are emphasized, including as fillers, monomers, and initiators. Moreover, typical applications of CD/polymer composites in light-emitting diodes, fluorescent printing, and biomedicine are outlined. Finally, we discuss current problems and speculate on their future development.

Preparation of highly crystalline nitrogen-doped carbon dots and their application in sequential fluorescent detection of Fe3+ and ascorbic acid

Carbon dots (CDs) have been a new class of fascinating carbon-based fluorescent nanomaterials. In the present work, new N-doped CDs with highly crystalline graphite structures are prepared from renewable precursors, chitosan and tartaric acid, and are well characterized. The prepared CDs are applied as a biocompatible fluorescent sensor for the sequential detection of Fe³⁺ and AA. Among various transition metal ions, Fe³⁺ can selectively quench the fluorescence of CDs. Upon the further addition of AA, the quenched fluorescence of CDs is then restored as Fe³⁺ is reduced to Fe²⁺ by AA, which can be utilized for the fluorescent determination of AA. A good linear relationship in the range of 0-150 μM of AA concentration is established with a low detection limit of 0.02 µM. Moreover, the practical applications of this fluorescent sensing method in measurement of AA in food samples are successfully realized with satisfactory results.

Antibacterial Activity Against Methicillin-Resistant Staphylococcus aureus of Colloidal Polydopamine Prepared by Carbon Dot Stimulated Polymerization of Dopamine

A simple one-step process for the polymerization of dopamine has been developed using nitrogen-doped carbon dots (N@C–dots) as the sole initiator. The synthesized amorphous polydopamine (PDA)-doped N@C–dots (PDA–N@C–dots composite) exhibited a negative charge of –39 mV with particle sizes ranging from 200 to 1700 nm. The stable colloidal solution was active against methicillin-resistant Staphylococcus aureus (MRSA), a Gram-negative bacterium. The strong adhesion of the polymer to the bacterial membrane resulted in a limited diffusion of nutrients and wastes in and out of the cell cytosol, which is a generic mechanism to trigger cell death. Another possible route is the autoxidation of the catechol moiety of PDA to form quinone and release reactive oxygen species (ROS) such as superoxide radicle and hydrogen peroxide, two well-known ROS with antimicrobial properties against both Gram-negative and Gram-positive bacteria.

Sensitively and Selectively Detect Biothiols by Using Fluorescence Method and Resonance Light Scattering Technique Simultaneously

In this paper, we designed a new quantitative and qualitive detection method for biothiols by using fluorescence method and resonance light scattering (RLS) technique. Nitrogen doped carbon quantum dots (C/N-dots) were obtained from tartaric acid and ethylenediamine by hydrothermal method, and then their morphology and optical properties were characterized by different techniques. A detection system consisting of C/N-dots and Ag⁺ complex was established. In this system, C/N-dots possessed the photoluminescent property and the Ag⁺ complex owned the RLS property, so, by combining the two luminescent properties to achieve complementary advantages, we could detect biothiols and solve the problem of distinguishing between Cys and GSH. Additionally, we optimized detecting conditions and investigated the detection mechanism of fluorescence quenching and RLS detecting. Results showed that the analytical response of fluorescence was linear in the range 0–140 μM and the detection limit (LOD) was calculated to be 6.6 μM for Cys, and the addition of GSH had no effect on fluorescence. RLS response ranges were 0–167 μM for Cys and 0–200 μM for GSH, with LOD down to 64 nM and 74 nM, respectively. Furthermore, the probe was successfully used for detecting Cys in fetal bovine serum (FBS) samples by fluorescence method, and also, by RLS technique, the content of GSH in FBS samples was detected.