Fluorescent Carbon Nanomaterials Research Articles

Carbon Nanomaterial Fluorescent Probes and Their Biological Applications.

Fluorescent carbon nanomaterials have broadly useful chemical and photophysical attributes that are conducive to applications in biology. In this review, we focus on materials whose photophysics allow for the use of these materials in biomedical and environmental applications, with emphasis on imaging, biosensing, and cargo delivery. The review focuses primarily on graphitic carbon nanomaterials including graphene and its derivatives, carbon nanotubes, as well as carbon dots and carbon nanohoops. Recent advances in and future prospects of these fields are discussed at depth, and where appropriate, references to reviews pertaining to older literature are provided.

Synthesis and Characterization of Optical Properties of Carbon Quantum Dots (CQD) Based on Mustard Green (Brassica juncea L) Leaf with Urea Addition

Carbon quantum dots (CQDs) are a class of fluorescent carbon nanomaterials. Carbon quantum dots (CQDs) were synthesized in this work from Mustard Leaves (Brassica juncea L) with the Addition of Urea via a microwave-assisted reflux method. This research aims to characterize CQDs' optical properties, energy gap, and emission under UV light computationally and experimentally. The studied optical properties obtained the maximum absorption peak observed from the UV-Vis spectrum of CQDs without urea shown at 233 nm. The UV-Vis spectrum of CQDs with the addition of urea (1 g, 1.5 g, and 2 g urea) has maximum absorption peaks at 424 nm, 422 nm, and 418 nm. The addition of urea causes a shift in the peak of the UV-Vis absorption spectrum towards red wavelengths (redshift). CQDs display bright green emissions when exposed to UV irradiation. In this work, the structures of CQDs of various forms (CQD-24, CQD-54, CQD-24-NH2, CQD-54-NH2) are theoretically studied in detail, and the results present both models (CQD-24, CQD-54) shows that the calculation results are in accordance with the experimental results, namely having a maximum UV-Vis absorption at 233 nm and in the range 200-400 nm. The results of calculations based on experiments show the same trend, namely that with the addition of urea, there is a shift in the absorption peak (redshift). The gap energy obtained also decreased with the addition of urea. CQDs solution emits yellow-green light.

Recent advances in carbon dots-based chromatographic separation materials

Chromatographic column is the core of chromatographic separation, and chromatographic separation material is considered the soul of the chromatographic column. The type and characteristics of the chromatographic separation material directly determine the separation mode and performance of chromatographic columns. The development and preparation of separation materials with novel structures and good separation performance is an ongoing hotspot in chromatography research. Given rapid developments in nanoscience and technology, nanomaterials with unique surface functional groups and large specific surface areas have attracted extensive attention and great interest from researchers in the field of separation science. Carbon dots (CDs), a new type of zero-dimensional fluorescent carbon nanomaterials, have been widely used in bioimaging, light-emitting diodes, sensing, catalysis, drug delivery, and other applications since they were first reported in 2004. These nanomaterials present several advantages over other types of separation materials, including a simple preparation process, low toxicity, easy functionalization, excellent biocompatibility, and photobleaching resistance. In addition, compared with traditional carbon nanomaterials such as graphene and carbon nanotubes, CDs have abundant surface functional groups, nanoscale sizes, and moderate adsorption properties. Hence, when CDs-based new materials are applied as a stationary phase for column chromatography, they can provide rich reaction sites and ensure the uniformity of the chromatographic packing process. The use of CDs can effectively avoid the peak-tailing phenomenon caused by the strong interaction of large π-conjugated systems with some analytes and improve the efficiency of the chromatographic column. As such, these nanomaterials show good application prospects in the field of chromatographic separation. In this review, the development history, classification, and synthesis strategies of CDs are briefly described. We then focus on the development of CDs-based chromatographic separation materials by systematically reviewing the recent advances in the use of CDs-based materials as a stationary phase for high-performance liquid chromatography (including hydrophilic interaction, reversed-phase, mixed-mode, and chiral chromatography), gas chromatography, and capillary electrochromatography, with special emphasis on the preparation methods and applications of various stationary phases. Finally, the development prospects of CDs and future research efforts on these materials are also analyzed and discussed. This review can provide guidance on the rational design and application of new CDs-based chromatographic separation materials.

Carbon Dots: From Synthesis to Unraveling the Fluorescence Mechanism.

Carbon dots (CDs) being a new type of carbon-based nanomaterial have attracted intensive interest from researchers owing to their excellent biophysical properties. CDs are a class of fluorescent carbon nanomaterials that have emerged as a promising alternative to traditional quantum dots and organic dyes in applications including bioimaging, sensing, and optoelectronics. CDs possess unique optical properties, such as tunable emission, facile synthesis, and low toxicity, making them attractive for many applications in biology, medicine, and environmental areas. The synthesis of CDs is achievable by a variety of methods, including bottom-up and top-down approaches, involving the use of different carbon sources and surface functionalization strategies. However, understanding the fluorescence mechanism of CDs remains a challenge. Various mechanistic models have been proposed to explain their origin of luminescence. This review summarizes the recent developments in the synthesis and functionalization of CDs and provides an overview of the current understanding of the fluorescence mechanism.

Carbon dots stabilized photoluminescent blue phase liquid crystals.

Blue phase liquid crystals (BPLCs) have significant potential in the field of liquid crystal displays (LCDs) and are proposed as potential next-generation of LCDs candidates. However, BPLCs do not emit light directly and need an extra backlight device. As a result, the blue phase liquid crystal display retains the disadvantages of low brightness and low energy efficiency, which remarkably limit its application. Recently, as a kind of novel fluorescent carbon nanomaterials, carbon dots (CDs) have captured considerable attention because of their excellent optical properties. Here, CDs were directly synthesized by a simple solvothermal method and introduced into BPLCs. By combining the excellent optical properties of CDs with the blue phase liquid crystal system, the photoluminescent blue phase liquid crystals (CDs-BPLCs) with self-photoluminescence are prepared. Meanwhile, the stability of BPLCs can be improved by CDs. Such CDs-BPLCs have enormous potential in the development of novel energy-saving display devices.

Fluorescent carbon nanomaterials from coal and its derivatives: structure, properties, and applications

Fluorescent carbon nanomaterials from coal and its derivatives: structure, properties, and applications

“Grafting from” Enabled Stretchable and Highly Fluorescent Carbon Quantum Dot–Polyisoprene Elastomers

Achieving polymer nanocomposites with improved elasticity and stable mechanical and fluorescence properties remains challenging due to the aggregation tendency of fluorescent carbon nanomaterials, particularly for a polymer with no functional groups. To alleviate the aforementioned issues, the “grafting from” method can be employed via covalent bonding design. Herein, we exploit the “grafting from” method coupled with reversible fragment-added chain transfer polymerization to construct soft polyisoprene (PI) chains onto a photostable nitrogen, sulfur, and phosphorus-doped carbon quantum dot (NSP–CQD) surface for the preparation of flexible fluorescent NSP–CQDs-grafted-polyisoprene (NSP–CQDs-g-PIx) nanocomposite films. By tuning the molecular weight of PI in NSP–CQDs-g-PIx (x = 8, 13, and 18 kg mol–1), the elastic and mechanical properties can be tailored. Upon an intense tensile cyclic test, the NSP–CQDs-g-PI18K generates remarkable elasticity, indicated by the absence of permanent deformation or residual strain even after multiple loading–unloading tests up to 50 times. Moreover, compared with the blending method that tends to cause reduced photoluminescence properties due to the NSP–CQD agglomeration, the grafting method intelligibly maintains the fluorescence property. This study concludes that “grafting from” is a feasible method for fabricating CQD-loaded composites, which have great potential to meet the demand for advanced stretchable and flexible organic electronic devices.

Comprehensive advances in the synthesis, fluorescence mechanism and multifunctional applications of red-emitting carbon nanomaterials.

Red emitting fluorescent carbon nanomaterials have drawn significant scientific interest in recent years due to their high quantum yield, water-dispersibility, photostability, biocompatibility, ease of surface functionalization, low cost and eco-friendliness. The red emissive characteristics of fluorescent carbon nanomaterials generally depend on the carbon source, reaction time, synthetic approach/methodology, surface functional groups, average size, and other reaction environments, which directly or indirectly help to achieve red emission. The importance of several factors to achieve red fluorescent carbon nanomaterials is highlighted in this review. Numerous plausible theories have been explained in detail to understand the origin of red fluorescence and tunable emission in these carbon-based nanostructures. The above advantages and fluorescence in the red region make them a potential candidate for multifunctional applications in various current fields. Therefore, this review focused on the recent advances in the synthesis approach, mechanism of fluorescence, and electronic and optical properties of red-emitting fluorescent carbon nanomaterials. This review also explains the several innovative applications of red-emitting fluorescent carbon nanomaterials such as biomedicine, light-emitting devices, sensing, photocatalysis, energy, anticounterfeiting, fluorescent silk, artificial photosynthesis, etc. It is hoped that by choosing appropriate methods, the present review can inspire and guide future research on the design of red emissive fluorescent carbon nanomaterials for potential advancements in multifunctional applications.

Stability of carbon quantum dots: a critical review.

Carbon quantum dots (CQDs) are fluorescent carbon nanomaterials with unique optical and structural properties that have drawn extensive attention from researchers in the past few decades. Environmental friendliness, biocompatibility and cost effectiveness of CQDs have made them very renowned in countless applications including solar cells, white light-emitting diodes, bio-imaging, chemical sensing, drug delivery, environmental monitoring, electrocatalysis, photocatalysis and other related areas. This review is explicitly dedicated to the stability of CQDs under different ambient conditions. Stability of CQDs is very important for every possible application and no review has been put forth to date that emphasises it, to the best of our knowledge. This review's primary goal is to make the readers cognizant of the importance of stability, ways to assess it, factors that affect it and proposed ways to enhance the stability for making CQDs suitable for commercial applications.

Potentialities of fluorescent carbon nanomaterials as sensor for food analysis.

Food safety and quality are among the most significant and prevalent research areas worldwide. The fabrication of appropriate technical procedures or devices for the recognition of hazardous features in foods is essential to safeguard food materials. In the recent era, developing high-performance sensors based on carbon nanomaterial for food safety investigation has made noteworthy progress. Hence this review briefly highlights the different detection approaches (colorimetric sensor, fluorescence sensor, surface-enhanced Raman scattering, surface plasmon resonance, chemiluminescence, and electroluminescence), functional carbon nanomaterials with various dimensions (quantum dots, graphene quantum dots) and detection mechanisms. Further, this review emphasizes the assimilation of carbon nanomaterials with optical sensors to identify multiple contaminants in food products. The insights of carbon-based nanomaterials optical sensors for pesticides and insecticides, toxic metals, antibiotics, microorganisms, and mycotoxins detection are described in detail. Finally, the opportunities and future perspectives of nanomaterials-based optical analytical approaches for detecting various food contaminants are discussed.

Recent advances in fluorescent 0D carbon nanomaterials as artificial nanoenzymes for optical sensing applications

Recent advances in fluorescent 0D carbon nanomaterials as artificial nanoenzymes for optical sensing applications

The facile detection and micromechanism of ATMP and DTPMP by fluorescence sensor based on nitrogen-doped carbon nanomaterials

In the present work, the N-doped fluorescent carbon nanomaterials (NCMs) were prepared. Fe3+ quenched the fluorescence of NCMs effectively, while the addition of different concentrations of ATMP or DTPMP can restore the fluorescence intensity of NCMs to different degrees. Therefore, the Fe-NCMs fluorescent probe can quantitatively detect ATMP or DTPMP, and the detection limit (LOD) of ATMP and DTPMP was 0.479 μΜ and 0.254 μΜ, respectively. The fluorescence quenching mechanism of NCMs by Fe3+ was revealed by UV–vis absorption spectra and the fluorescence lifetime analysis, the results showed that the fluorescence quenching was a combination of static and dynamic quenching. Moreover, based on Density Function Theory (DFT) calculation, basin analysis, topology analysis of atoms in molecules (AIM), electron localization function (ELF) analysis, and bond order density (BOD) analysis were firstly combined to reveal the difference in fluorescence restoration degree between the two organic phosphonates on Fe-NCMs. The detection mechanism of ATMP and DTPMP by Fe-NCMs was explained from a microscopic point of view.

Preparation of carbon-based quantum dots and metal nanocomposites and their applications in sensors

Carbon-based quantum dots, zero-dimensional carbon nanomaterials that can be widely used with a particle size of 1-10nm, can be widely used in fluorescent carbon nanomaterials in thousands of households. This article will first elaborate on carbon-based quantum dots and metal nanomaterials and explain the related methods of making them. First, the top-down method is used to prepare carbon quantum dots, the fluorescence mechanism of carbon-based quantum dots is used, and the electrochemical method is used at high temperature. Carbonization burning method and laser ablation method, the mixture of graphite powder and polyethylene glycol ester is hot pressed, baked, and cut in an argon atmosphere to obtain strong fluorescent carbon-based quantum dots, and then explain the immune algorithm to prepare nanocomposites for cermet mold materials, use the diversity of antibodies to calculate the concentration and quantity, and calculate its viability. Through regression coefficients, it can be shown that the immune algorithm is used to optimize the component optimization design of Ti(C,N)-based nanocomposite cermet mold materials. The effect is better.

Recent Advances in Carbon Dots for In Vitro/Vivo Fluorescent Bioimaging: A Mini-Review.

As a new type of “zero-dimensional” fluorescent carbon nanomaterials, carbon dots (CDs) have some unique optical and chemical properties, they are being explored for a variety of applications in bio-related fields, such as bioimaging, biosensors, and therapy. This review mainly summarizes the recent progress of CDs in bioimaging. The overview of this review can be roughly divided into two categories: (1) In vitro bioimaging based on CDs in different cells and important organelles. (2) The distribution, imaging and application of CDs in mice and zebrafish. In addition, this review also points out the potential advantages and future development directions of CDs for bioimaging, which may promote the development of CDs in the field of bioimaging.

Template-Free Synthesis of Porous Fluorescent Carbon Nanomaterials with Gluten for Intracellular Imaging and Drug Delivery.

A series of carbon nanomaterials, including carbon dots, carbon nanorings (CNRs), and porous carbon nanoballs, were facilely prepared by a template-free hydrothermal treatment of gluten as the sole carbon source. Driven by the hydrophobicity interaction, a concentration-dependent self-assembly of gluten was observed in an aqueous solution, leading to the subsequent formation of different morphologies of carbon nanomaterials in a hydrothermal treatment. Among these carbon nanomaterials, the CNRs exhibit bright photoluminescence with a quantum yield of 47.0%. Furthermore, CNRs also have a large surface area and low toxicity, making them an excellent drug carrier for chemotherapeutics. A model drug molecule doxorubicin (DOX) was successfully loaded on the CNRs, and the CNRs-DOX complexes exhibit a pH-dependent DOX release behavior. Compared with free DOX, the CNRs-DOX complexes can induce a higher level of apoptosis and lower level of necrosis, showing promise as anticancer agents.

Evaluation of Thermal Behavior and Properties of Carbon Dots Prepared by Green Synthesis

Carbon quantum dots are highly fluorescent, non-toxic, thermally stable, and water-soluble novel carbon nanomaterials. The dominance of quantum behavior has drawn scientists’ interest due to their good biocompatibility, low toxicity, high physicochemical and photochemical stability, and ease of synthesis. Carbon dots have shown applications in optoelectronics, photovoltaics, photocatalyst, biomedical such as biosensing, bioimaging, drug delivery, and detection for heavy metal ions in food and water samples. In this paper, we reported the microwave-assisted green synthesis of carbon dots using sweet lime as a carbon source and ethyl diamine as the surface passivating agent. The change in the optical and thermal properties are studied and analyzed with a change in the concentration of EDA in carbon dots. Synthesized samples are characterized by Dynamic Light Scattering and Zeta potential particle sizer to analyze the effect of EDA concentration on the distribution of particle size in the samples and change in surface charge of as-prepared carbon dots. The optical parameters are studied with UV- Visible absorption spectroscopy. Composition and molecular bonding are confirmed by Fourier Transform Infrared Spectroscopy. Thermal behavior and kinematics are studied by simultaneous Thermogravimetric Analyzer and Differential Scanning Calorimetry.

Fluorescent carbon nano-materials from coal-based precursors: unveiling structure–function relationship between coal and nano-materials

Fluorescent carbon nano-materials from coal-based precursors: unveiling structure–function relationship between coal and nano-materials

Study on novel fluorescent carbon nanomaterials in food analysis

One of the most significant nanobiotechnology and nanomaterial science areas today is the production of novel sensors and biosensors with applications in the food industry. Carbon quantum dots (CQDs) are a new generation of carbon nanoparticles with a lot of potential for food analysis. CQDs with robust physicochemical properties are one of the most recently researched carbon nanomaterials. This material has outstanding optical properties such as light persistence, photobleaching tolerance, photoluminescence, and the advantages of fast functionalization and strong biocompatibility, rendering it an excellent raw material for sensing devices. Thanks to its considerable features such as fast result outputs, low expense, ease of service, and high sensitivity, fluorescence analysis has tremendous potential for food protection. The aim of this article is to familiarise yourself with carbon points, their synthesis methods, and their optical properties. Finally, fluorescence sensors can be used to detect food additives, heavy metals, bacteria, insecticide residues, antibiotics, and nutritional components in food samples. CQDs' problems and opportunities in the area of food safety were also addressed.

Carbon quantum dot preparation and application to detecting active ingredients in traditional Chinese medicine

Abstract Carbon quantum dots (CQDs) are fluorescent carbon nanomaterials that have been applied to biology, medicine, and optoelectronics, owing to their significant advantages such as simple synthesis methods, low cost, and widely available sources of raw synthesis materials. This review summarizes CQD preparation methods, which include hydrothermal and microwave-assisted synthesis methods, as well as separation methods such as centrifugation, dialysis, and filtration. Additionally, we review the application of CQDs in the detection of active ingredients, primarily phenolic compounds, in traditional Chinese medicine. We also discuss the quenching mechanism of CQD fluorescence using the active ingredients of traditional Chinese medicine. Limitations such as insufficient test selectivity, weak fluorescence intensity, and an unclear quantitative relationship between preparation methods and properties should be resolved for the efficient use of CQDs to detect active ingredients in Chinese medicine.

Precise Blood Glucose Sensing by Nitrogen-Doped Graphene Quantum Dots for Tight Control of Diabetes

Graphene quantum dots (GQD) are novel fluorescent carbon nanomaterials based on a graphite structure. Thanks to extraordinary properties such as high surface area and enhanced prevalent optical properties, they have received more interest for special applications. Glucose sensing is a critical factor for the diagnosis, and treatment of diabetes plays an important role and could contribute to the monitoring of diabetes and other related parameters, which has been effectively underscoring the health society. Detecting glucose has been cultivated through different systems, for example, electrochemical or optical techniques. Novel transducers made with GQD that fluorescent coordinate methods have considered the improvement of cutting-edge glucose sensors with prevalent affectability and accommodation. Currently, detection of glucose by nitrogen-doped GQD frameworks concerning the determined objectives has been considerably considered. Here, we explored the properties of fluorescent nitrogen-doped GQD as an excellent and effective index that significantly could promote nitrogen-doped GQDs and make them an appropriate candidate for detecting glucose.