Carbon Dots Boost dsRNA Delivery in Plants and Increase Local and Systemic siRNA Production

Carbon Dots: Synthesis, Characterizations, and Recent Advancements in Biomedical, Optoelectronics, Sensing, and Catalysis Applications

Carbon nanodots (CNDs), a fascinating carbon-based nanomaterial (typical size 2-10 nm) owing to their superior optical properties, high biocompatibility, and cell penetrability, have tremendous applications in different interdisciplinary fields. Here, in this Review, we first explore the superiority of CNDs over other nanomaterials in the biomedical, optoelectronics, analytical sensing, and photocatalysis domains. Beginning with synthesis, characterization, and purification techniques, we even address fundamental questions surrounding CNDs such as emission origin and excitation-dependent behavior. Then we explore recent advancements in their applications, focusing on biological/biomedical uses like specific organelle bioimaging, drug/gene delivery, biosensing, and photothermal therapy. In optoelectronics, we cover CND-based solar cells, perovskite solar cells, and their role in LEDs and WLEDs. Analytical sensing applications include the detection of metals, hazardous chemicals, and proteins. In catalysis, we examine roles in photocatalysis, CO2 reduction, water splitting, stereospecific synthesis, and pollutant degradation. With this Review, we intend to further spark interest in CNDs and CND-based composites by highlighting their many benefits across a wide range of applications.

Exogenous Application of dsRNA for Protection against Tomato Leaf Curl New Delhi Virus

Tomato leaf curl New Delhi virus (ToLCNDV) is an emerging plant pathogen, fast spreading in Asian and Mediterranean regions, and is considered the most harmful geminivirus of cucurbits in the Mediterranean. ToLCNDV infects several plant and crop species from a range of families, including Solanaceae, Cucurbitaceae, Fabaceae, Malvaceae and Euphorbiaceae. Up to now, protection from ToLCNDV infection has been achieved mainly by RNAi-mediated transgenic resistance, and non-transgenic fast-developing approaches are an urgent need. Plant protection by the delivery of dsRNAs homologous to a pathogen target sequence is an RNA interference-based biotechnological approach that avoids cultivating transgenic plants and has been already shown effective against RNA viruses and viroids. However, the efficacy of this approach against DNA viruses, particularly Geminiviridae family, is still under study. Here, the protection induced by exogenous application of a chimeric dsRNA targeting all the coding regions of the ToLCNDV DNA-A was evaluated in zucchini, an important crop strongly affected by this virus. A reduction in the number of infected plants and a delay in symptoms appearance, associated with a tendency of reduction in the viral titer, was observed in the plants treated with the chimeric dsRNA, indicating that the treatment is effective against geminiviruses but requires further optimization. Limits of RNAi-based vaccinations against geminiviruses and possible causes are discussed.

Nanoparticle-mediated dsRNA delivery for precision insect pest control: a comprehensive review

Nanoparticle-based delivery systems have emerged as powerful tools in the field of pest management, offering precise and effective means of delivering double-stranded RNA (dsRNA), a potent agent for pest control through RNA interference (RNAi). This comprehensive review aims to evaluate and compare various types of nanoparticles for their suitability in dsRNA delivery for pest management applications. The review begins by examining the unique properties and advantages of different nanoparticle materials, including clay, chitosan, liposomes, carbon, gold and silica. Each material's ability to protect dsRNA from degradation and its potential for targeted delivery to pests are assessed. Furthermore, this review delves into the surface modification strategies employed to enhance dsRNA delivery efficiency. Functionalization with oligonucleotides, lipids, polymers, proteins and peptides is discussed in detail, highlighting their role in improving stability, cellular uptake, and specificity of dsRNA delivery.This review also provides valuable guidance on choosing the most suitable nanoparticle-based system for delivering dsRNA effectively and sustainably in pest management. Moreover, it identifies existing knowledge gaps and proposes potential research directions aimed at enhancing pest control strategies through the utilization of nanoparticles and dsRNA.

Nanoplatforms for the Delivery of Nucleic Acids into Plant Cells

Nanocarriers are widely used for efficient delivery of different cargo into mammalian cells; however, delivery into plant cells remains a challenging issue due to physical and mechanical barriers such as the cuticle and cell wall. Here, we discuss recent progress on biodegradable and biosafe nanomaterials that were demonstrated to be applicable to the delivery of nucleic acids into plant cells. This review covers studies the object of which is the plant cell and the cargo for the nanocarrier is either DNA or RNA. The following nanoplatforms that could be potentially used for nucleic acid foliar delivery via spraying are discussed: mesoporous silica nanoparticles, layered double hydroxides (nanoclay), carbon-based materials (carbon dots and single-walled nanotubes), chitosan and, finally, cell-penetrating peptides (CPPs). Hybrid nanomaterials, for example, chitosan- or CPP-functionalized carbon nanotubes, are taken into account. The selected nanocarriers are analyzed according to the following aspects: biosafety, adjustability for the particular cargo and task (e.g., organelle targeting), penetration efficiency and ability to protect nucleic acid from environmental and cellular factors (pH, UV, nucleases, etc.) and to mediate the gradual and timely release of cargo. In addition, we discuss the method of application, experimental system and approaches that are used to assess the efficiency of the tested formulation in the overviewed studies. This review presents recent progress in developing the most promising nanoparticle-based materials that are applicable to both laboratory experiments and field applications.

Carbon-Based Fluorescent Nano-Biosensors for the Detection of Cell-Free Circulating MicroRNAs

Currently, non-communicable diseases (NCDs) have emerged as potential risks for humans due to adopting a sedentary lifestyle and inaccurate diagnoses. The early detection of NCDs using point-of-care technologies significantly decreases the burden and will be poised to transform clinical intervention and healthcare provision. An imbalance in the levels of circulating cell-free microRNAs (ccf-miRNA) has manifested in NCDs, which are passively released into the bloodstream or actively produced from cells, improving the efficacy of disease screening and providing enormous sensing potential. The effective sensing of ccf-miRNA continues to be a significant technical challenge, even though sophisticated equipment is needed to analyze readouts and expression patterns. Nanomaterials have come to light as a potential solution as they provide significant advantages over other widely used diagnostic techniques to measure miRNAs. Particularly, CNDs-based fluorescence nano-biosensors are of great interest. Owing to the excellent fluorescence characteristics of CNDs, developing such sensors for ccf-microRNAs has been much more accessible. Here, we have critically examined recent advancements in fluorescence-based CNDs biosensors, including tools and techniques used for manufacturing these biosensors. Green synthesis methods for scaling up high-quality, fluorescent CNDs from a natural source are discussed. The various surface modifications that help attach biomolecules to CNDs utilizing covalent conjugation techniques for multiple applications, including self-assembly, sensing, and imaging, are analyzed. The current review will be of particular interest to researchers interested in fluorescence-based biosensors, materials chemistry, nanomedicine, and related fields, as we focus on CNDs-based nano-biosensors for ccf-miRNAs detection applications in the medical field.

Preparation of Multicolour Solid Fluorescent Carbon Dots for Light-Emitting Diodes Using Phenylethylamine as a Co-Carbonization Agent

Carbon dots (CDs), as a new type of photoluminescent nanomaterial, have attracted extensive attention in various fields because of their unique luminescence properties. However, CDs will exhibit fluorescence quenching in the solid state or aggregate state, which limits their application. In this paper, a unique strategy is proposed to regulate solutions to achieve multicolour fluorescence of CDs in the solid state. We report the successful preparation of orange, green and blue solid fluorescent CDs using citric acid, urea and phenylethylamine as precursors and methanol, ethanol and water as solvents, respectively. The solid-state fluorescence of CDs may be caused by the linkage of the phenylethyl structure to the surface of CDs during formation, which effectively disperses the CDs and prevents π–π interactions between graphitized nuclei. Meanwhile, multicolour solid fluorescent CDs are realized by adjusting the solvent in the preparation process. Based on the excellent fluorescence properties of CDs, orange, green and blue light-emitting diodes (LEDs) are prepared. A white LED (WLED) can be obtained by mixing the three colours of solid fluorescent CDs, which shows the application potential of CDs in display lighting equipment.

Solvent-Free Preparation of Tannic Acid Carbon Dots for Selective Detection of Ni2+ in the Environment

Carbon dots (CDs) are widely used nanomaterials that not only exhibit good biocompatibility and photostability, but also benefit from a simple preparation process and easy functionalization, making them promising for broad applications in the fields of heavy metal ion detection and optoelectronic devices. Based on the excellent optical properties of CDs and the current situation of increasing energy shortages, this paper selects the natural polyphenolic compound tannic acid (TA) found in biomass materials as the carbon source and innovatively adopts a simple and convenient solvent-free pyrolysis method without auxiliary reagents or solvents. The CDs with good water solubility and certain fluorescence properties were directly prepared under the condition of high temperature, and the obtained CDs exhibited blue fluorescence, and a high QY of 35.4% was obtained at 300 °C. The analysis and results demonstrate the selectivity of these CDs for the detection of various metal ion solutions. In particular, these CDs are sensitive to Ni²⁺ and can be used as fluorescent sensors for the efficient and sustainable detection of Ni²⁺, whereas previous sensors were often specific to Fe³⁺ and Hg²⁺. Thus, a new sensing technique has been developed for the detection of Ni²⁺ to achieve more sensitive and rapid detection.