A Review on Characterization Techniques for Carbon Quantum Dots and Their Applications in Agrochemical Residue Detection

Carbon quantum dots in spectrofluorimetric analysis: A comprehensive review of synthesis, mechanisms and multifunctional applications

Carbon quantum dots (CQDs), as a representative nanomaterial, have demonstrated promising applications in fluorescence analysis owing to their unique optical properties, low cytotoxicity and exceptional biocompatibility. This review systematically summarizes recent advances in synthesis strategies, detection mechanisms and applications of CQDs for sensing metal ions (e.g., Hg2+, Fe3+, Cu2+), small molecules (e.g., biomolecules, pharmaceuticals, azo dyes) and proteins. Hybridization of CQDs with functional materials has been shown to significantly enhance their photoluminescence properties while optimizing detection sensitivity and selectivity. The article critically examines fundamental detection mechanisms, especially fluorescence quenching and further outlines design strategies for fluorescence probes based on "on-off" switching or ratio signaling. Moreover, current challenges are analyzed, such as the need for synthetic protocol standardization, in-depth exploration of heteroatom-doped CQDs, expansion of detectable analytes and rational design of fluorescence turn-on probes. Future prospects in environmental monitoring, biomedical diagnostics and pharmaceutical analysis are also highlighted. This comprehensive review offers critical insights to guide the rational design and application of advanced CQD-based hybrid systems.

Polystyrene foam-based pipette-tip Micro-solid phase extraction (PFPT-μSPE) using Ni-MOF@S-CQDs nanocomposite: A novel method for efficient extraction of Lead from water and food samples

A novel Ni-MOF@S-CQDs nanocomposite was synthesized directly into the pores of a polystyrene foam. It was characterized using FTIR, XRD, SEM, and SEM-EDX techniques. The adsorbent was effectively applied for the extraction of Pb (II) from water, juice, and iced tea samples, followed by analysis using UV-VIS spectrometry. Various analytical factors, including pH, adsorbent amount, adsorption and desorption times, and sample volume, were studied. Under the optimum conditions, the analytical features were obtained; the LDR of 50-5000 μg L-1, the LOD of 15 μg L-1, and the RSDs% of 2.0 and 4.0 for intra-day and inter-day, respectively. The preconcentration (PF) and the enrichment (EF) factors of 30, the factor of 28.5, and the extraction efficiency (EE) of 95 % were obtained. Certified reference materials (CRMs) were used to validate the novel Polystyrene Foam-Pipette Tip Micro-Solid Phase Extraction (PFPT-μSPE) technique. This study is eco-friendly, accurate, and economical for the extraction of Pb (II) from water and beverage samples.

Application Progress of Carbon Quantum Dot Composites in Fluorescent Detection of Food Safety

Carbon quantum dots (CQDs) have emerged as promising nanomaterials due to their unique optical properties, excellent biocompatibility, and cost-effectiveness. This review highlights recent advances in CQD-based composite materials and their applications in fluorescence detection, particularly in food safety. Combining CQDs with diverse materials enhances their fluorescence performance, stability, and selectivity, enabling the sensitive detection of various food contaminants. CQD composites offer significant improvements over conventional methods, including lower detection limits, faster response times, and broader applicability. Key areas of focus include the detection of pesticide residues, veterinary drug residues, heavy metal ions, and pathogenic bacteria in complex food matrices. Advanced doping and hybridization strategies, such as heteroatom incorporation, further optimize their optical and chemical properties. These innovations address critical challenges in food safety monitoring, paving the way for more effective and accessible detection technologies. Future developments in CQD composites are expected to expand their applications, ensuring enhanced food quality and public health protection.

Synthesis, Characterization, and Applications of Carbon Dots for Determination of Pharmacological and Biological Samples: A Review

Carbon dots (CDs) are a novel category of carbon-based nanomaterials characterized by their small size, often less than 10 nm. CDs physical, chemical, and optical properties can be tuned using one-pot assembly. Because of their non-toxicity, biocompatibility, chemical and physical responsiveness, photo- and chemical-bleaching resistance, and low cost, nanoparticles have become incredibly versatile. They find various applications in detecting inorganic substances, bio sensing, visualizing cells, studying biological processes in live cells, and aiding in medication delivery. Additionally, CDs exhibit versatility in electronics and energy storage, making them promising candidates for applications in solar cells, light-emitting diodes, and supercapacitors. CDs are more photo stable for hours than typical fluorescent semiconductor quantum dots. Before applying CDs, they must be characterized. Techniques such as UV-VIS spectroscopy, fluorescence spectrophotometry, FT-IR, TEM, XRD, Raman spectroscopy, and NMR are commonly used to assess their photophysical and structural properties. This article review explores the synthesis, characterization applications of CDs in analytical techniques for the determination of various analytes. The article provides a detailed analysis of the different methodologies used to make nanomaterials and devices for the characterization of CDs. It also discusses the challenges that arise when using CDs in analytical techniques for detecting different analytes. The focus of this review is on accurately determining pharmaceutical and biological samples using CDs as sensing probes.

An immunosensor for the detection of N-(carboxymethyl)lysine - a diabetic biomarker

Carboxymethyl-lysine (CML) is a well-known lysine product that strongly correlates with type 2 diabetes mellitus (T2DM), and its elevated levels are significantly associated with renal impairment and T2DM-related complications. Thus, it is imperative to quantify CML levels and recognize the onset of hyperglycemia and its consequences. In this context, the development of an electrochemical immunosensor for the rapid and ultralow-level detection of CML was attempted. The fabrication of the working electrode involves the covalent immobilization of anti-CML/EDC-NHS on the surface of a carbon quantum dot (CQD)-modified glassy carbon electrode (GCE). The immunosensor exhibited two discrete linear concentration ranges of 0.5-5.0 ng mL-1 and 5.5-10.0 ng mL-1, with limits of detection and quantification of 0.027 and 0.087 ng mL-1 and 0.16 and 0.51 ng mL-1, respectively. The observed specificity and other merits of the sensor make it suitable for testing human plasma samples.

Synthesis, Characterization, Magnetic Properties, and Applications of Carbon Dots as Diamagnetic Chemical Exchange Saturation Transfer Magnetic Resonance Imaging Contrast Agents: A Review

Carbon dots (CDs) are metal-free carbon-based nanoparticles. They possess excellent photoluminescent properties, various physical properties, good chemical stability, high water solubility, high biocompatibility, and tunable surface functionalities, suitable for biomedical applications. Their properties are subject to synthetic conditions such as pH, reaction time, temperature, precursor, and solvent. Until now, a large number of articles on the synthesis and biomedical applications of CDs using their photoluminescent properties have been reported. However, their research on magnetic properties and especially, diamagnetic chemical exchange saturation transfer (diaCEST) in magnetic resonance imaging (MRI) is very poor. The diaCEST MRI contrast agents are based on exchangeable protons of materials with bulk water protons and thus, different from conventional MRI contrast agents, which are based on enhancements of proton spin relaxations of bulk water and tissue. In this review, various syntheses, characterizations, magnetic properties, and potential applications of CDs as diaCEST MRI contrast agents are reviewed. Finally, future perspectives of CDs as the next-generation diaCEST MRI contrast agents are discussed.

Advancing analytical chemistry with carbon quantum dots: a comprehensive review

Carbon Quantum Dots (CQDs) have gained significant attention as versatile nanomaterials in analytical chemistry due to their strong fluorescence, high sensitivity, and biocompatibility features. This review explores the synthesis, functionalization, and broad applications of CQDs in various analytical domains, including bioimaging, diagnostics, and environmental monitoring. CQDs' unique properties, such as tunable emission and ease of surface modification, enhance their performance in fluorescence and electrochemical sensing. CQDs present emerging applications in single-cell analysis, point-of-care diagnostics, and food safety. Technological advancements in green synthesis and hybrid nanomaterial integration are paving the way for more sustainable, efficient, and scalable analytical tools. However, challenges related to reproducibility, stability, and large-scale production persist, highlighting the need for continued research. The present review provides a comprehensive overview of CQDs' impact, emphasizing their potential to transform analytical chemistry through innovative applications and future breakthroughs.

Evolution of large stokes shift and non-radiative energy transfer phenomenon in sustainable blue-fluorescent CQDs upon subnanomolar detection of Acebrophylline

Carbon quantum dots (CQDs) have emerged as powerful fluorescent sensors for identifying harmful compounds in environmental and biological samples, due to their robust and adjustable emission characteristics. In this study, we explore CQDs (size ∼ 3 nm), as a probe, derived from Walnut Shell (WS) biomass waste for detecting Acebrophylline (AB), a respiratory disease medicine. From the selectivity studies, the calculated energy transfer between the CQDs (10 mM; donor) and AB (10 mM; acceptor) was found to be 64 %, attributed to the formation of a ground state complex, CQDs + AB. The CQDs demonstrated high selectivity and sensitivity to AB in concentrations between 1-100 μM with a detection limit of 0.142 nM (R2 = 0.991, Ka = 1.39194 × 10-3 M-1). Time-correlated single-photon counting (TCSPC) experiments validated the static quenching of CQDs (3.46 → 3.71 ns) when exposed to AB. The proposed detection method was successfully applied for detecting AB in human urine samples with a good recovery percentage (81 to 123 %; RSD ca. 1 %). After AB sensing, changes in the CQDs' crystalline nature, elemental composition, and chemical state were examined using XRD, XPS, and FTIR spectroscopy. Microscopy imaging techniques (FESEM, HRTEM, and AFM) confirmed morphological changes of CQDs from spherical to agglomerated with an average diameter of approximately 14 nm. Additionally, the impact of time, pH, and interferons on AB sensing was investigated. In vitro anti-inflammatory activity and in vivo bioimaging studies on zebrafish were also performed. This study highlights several advantages, including a cost-effective and eco-friendly approach for healthcare applications.

Aliphatic substrates-mediated unique rapid room temperature synthesis of carbon quantum dots for fenofibrate versatile analysis

BACKGROUND

The current synthetic strategies for carbon dots (CDs) are usually time-consuming, rely on complicated processes, and need high temperatures and energy. Recent studies have successfully synthesized CDs at room temperature. Unfortunately, most CDs synthesized at room temperature are obtained under harsh reaction conditions, prepared using aromatic precursors, or need a long time to generate. Therefore, an energy-free room-temperature rapid synthesis of CDs under mild conditions using aliphatic substrates is important. We aim to provide an innovative approach to synthesizing CDs to be used to develop the first fluorescence-based assay of the non-fluorescent anti-hyperlipidemic drug, fenofibrate.

RESULTS

We report an innovative, energy-free, and room-temperature preparation of fluorescent N-doped CDs utilizing aliphatic substrates in only 20 min. The synthesis was based on a self-exothermic Schiff base condensation reaction between methylglyoxal and ethylenediamine. The prepared CDs' antibacterial properties, biocompatibility, and cell-imaging ability were investigated. The fluorescence signal of the CDs was quantitively quenched upon adding increasing concentrations of fenofibrate in the range of 0.50-15.0 μg/mL. Therefore, the prepared CDs were applied as a nanosensor to develop the first fluorescence-based assay of fenofibrate. The reliability of the synthesized nanosensor was confirmed by the successful quantification of fenofibrate in pharmaceutical dosage forms, environmental water, weight loss herbal products, and dietary supplements. The obtained recovery ranged from 95.33 to 104.58 %. In addition, the minimal environmental impact of the developed fenofibrate sensing strategy was confirmed using the recently reported metrics.

SIGNIFICANCE AND NOVELTY

The key advantage of this work is the use of an energy-free approach to synthesize CDs rapidly under mild conditions without aromatic substrates. This opens a new window for the eco-friendly synthesis of CDs that avoids the drawbacks of the traditional methods. Additionally, it is the first fluorescence nanosensor for sensing fenofibrate in various matrices, avoiding the limitations of the previous methods, such as high cost, poor selectivity, and low sensitivity.

Development of a Facile and Green Synthesis Strategy for Brightly Fluorescent Carbon Dots from Various Waste Materials

Carbon dots (CDs) are fluorescent carbon-based nanomaterials with remarkable properties, making them more attractive than traditional fluorophores. Consequently, researchers focused on their development and application in fields such as sensing and bioimaging. One potential advantage of employing CDs is using organic waste as carbon precursors in their synthesis, providing a pathway for waste upcycling for a circular economy. However, waste-based CDs often have low fluorescence quantum yields (QYFL), limiting their practical applications. So, there is a need for a well-defined strategy to consistently produce waste-based CDs with appreciable QYFL, irrespective of the starting waste material. Herein, we developed a fabrication strategy based on the hydrothermal treatment of waste materials, using citric acid as a co-carbon precursor and ethylenediamine as N-dopant. This strategy was tested with various materials, including corn stover, spent coffee grounds, cork powder, and sawdust. The results showed consistently appreciable QYFL, reaching up to ~40 %. A Life Cycle Assessment (LCA) study demonstrated that producing these waste-based CDs has lower environmental impacts compared to CDs made solely from commercial reagents. Thus, we have established a framework for the environmentally friendly production of CDs by upcycling different waste materials without significant sacrifices in performance (QYFL).

Deep eutectic solvent-based magnetic molecular nanomaterials coupled with fluorescent carbon dots as a new strategy to highly enrich and sensitively detect doxycycline in food matrices

The highly selective enrichment and sensitive detection of antibiotics in food are crucial for human health, environmental monitoring, and management. In this study, deep eutectic solvents (DESs) were used as eco-friendly functional monomers, a magnetic molecular nanomaterial (DES-MMIP) coupled with carbon dots (CDs) was developed as a sensitive fluorescent probe for the selective enrichment and detection of trace amounts of doxycycline (DOX). Under optimal conditions, the method exhibited good linearity within 0.5-50 μg·L-1, a low detection limit of 0.34 nM for DOX detection. Furthermore, the DES-MMIP displayed excellent reusability and storage stability. With responsive, excellent selectivity and an eco-friendly nature, the established method is successful in detecting DOX in food matrices, with an average spiked recovery of 87.5 %-97.8 %. This strategy of integrating CDs and DES-MMIP for DOX detection conforms to the green concept of environmental protection and provides a new material and research approach for efficient analysis of DOX in complex matrices.

Turn-off fluorescent nanoprobe based on carbon dots synthesised by UV/H2O2 advanced oxidation for the detection of bisphenol A in canned foods

A novel assay was developed based on a turn-off fluorescent probe using the in situ generation of carbon dots (CDs) by means of UV/H2O2 advanced oxidation of carbohydrates for the detection of bisphenol A (BPA) in food. Different parameters involved in the synthesis of CDs for the direct recognition of BPA have been optimised and a sensing mechanism is outlined. The presence of H2O2 during CD synthesis causes a fluorescence enhancement due to the action of highly oxidant HO· radicals formed throughout the photochemical reaction. Phenolic compounds such as BPA can be easily degraded by the UV/H2O2 oxidation process, acting as a HO· free radical scavengers. This results in a decrease in the fluorescence that can be related to the BPA concentration. Under optimal conditions, a detection limit of 15 µg/kg of BPA and a quantification limit of 46 µg/kg of BPA in food samples were obtained. The repeatability and reproducibility, expressed as relative standard deviation and obtained for two concentration levels (30 µg/kg and 200 µg/kg, n = 5), were less than 2.0% and 6.4%, respectively. The proposed procedure was applied to the analysis of five samples of canned foods (sweet corn, peas, mushrooms, cockles and natural tuna), obtaining concentrations in the range 29.8-49.9 µg/kg of sample. Recovery studies were conducted at two concentration levels (100 and 400 µg BPA/kg of sample), resulting in recoveries in the range 99-101%. Method validation against two certified reference materials was also successfully performed. The experimental results demonstrate that the novel approach is suitable for the detection and quantification of BPA in canned foods.

Safety Evaluation of Carbon Dots in UM-UC-5 and A549 Cells for Biomedical Applications

BACKGROUNG

The rising complexity and associated side effects of cancer treatments highlight the need for safer and more effective therapeutic agents. Carbon-based nanomaterials such as CDs have been gaining prominence for their unique characteristics, opening avenues for diverse applications such as fluorescence imaging, drug and gene transport, controlled drug delivery, medical diagnosis, and biosensing. Despite promising advancements in research, it remains imperative to scrutinize the properties and potential cytotoxicity of newly developed CDs, ensuring their viability for these applications.

METHODS

We synthesized four N-doped CDs through a hydrothermal method. Cell viability assays were conducted on A549 and UM-UC-5 cancer cells at a range of concentrations and incubation times, both individually and with the chemotherapeutic agent 5-fluorouracil (5-FU).

RESULTS

The obtained results suggest that the newly developed CDs exhibit suitability for applications such as bioimaging, as no significant impact on cell viability was observed for CDs alone.

Fluorescent chemosensors facilitate the visualization of plant health and their living environment in sustainable agriculture

Globally, 91% of plant production encounters diverse environmental stresses that adversely affect their growth, leading to severe yield losses of 50-60%. In this case, monitoring the connection between the environment and plant health can balance population demands with environmental protection and resource distribution. Fluorescent chemosensors have shown great progress in monitoring the health and environment of plants due to their high sensitivity and biocompatibility. However, to date, no comprehensive analysis and systematic summary of fluorescent chemosensors used in monitoring the correlation between plant health and their environment have been reported. Thus, herein, we summarize the current fluorescent chemosensors ranging from their design strategies to applications in monitoring plant-environment interaction processes. First, we highlight the types of fluorescent chemosensors with design strategies to resolve the bottlenecks encountered in monitoring the health and living environment of plants. In addition, the applications of fluorescent small-molecule, nano and supramolecular chemosensors in the visualization of the health and living environment of plants are discussed. Finally, the major challenges and perspectives in this field are presented. This work will provide guidance for the design of efficient fluorescent chemosensors to monitor plant health, and then promote sustainable agricultural development.

Polyvinyl alcohol-derived-carbon quantum dots based fluorometric "On-Off" probe for moxifloxacin detection in milk and egg samples

Unconditional use of antibiotics triggered the process of bacterial resistance and causes major health problems. Nowadays, antibiotics majorly used in animals not only for infection treatment but also as mass promotor. The excess amount of antibiotics residue in animal derived foods which accelerate antibiotic resistance (ABR). So, here, a simple and quick carbon quantum dots(CQDs) based fluorometric "On-Off" probe was developed for detection of moxifloxacin (MOXI) in milk and egg samples. The CQDs emits blue emission and are uniformly distributed with average particle size 5.9 ± 0.22 nm. With MOXI, fluorescence intensity of CQDs at 372 nm decreased due to inner filter effect (IFE) and a new peak appeared at 508 nm correspondence to MOXI. The probe shows linear response with MOXI concentration varies as 0.025 µM - 15.0 µM with lower detection limit (LOD) of 6.34 nM. The real sample applicability test proved that the sensors have excellent efficacy for food applications.

Carbon Quantum Dots: Properties, Preparation, and Applications

Carbon quantum dots are a novel form of carbon material. They offer numerous benefits including particle size adjustability, light resistance, ease of functionalization, low toxicity, excellent biocompatibility, and high-water solubility, as well as their easy accessibility of raw materials. Carbon quantum dots have been widely used in various fields. The preparation methods employed are predominantly top-down methods such as arc discharge, laser ablation, electrochemical and chemical oxidation, as well as bottom-up methods such as templates, microwave, and hydrothermal techniques. This article provides an overview of the properties, preparation methods, raw materials for preparation, and the heteroatom doping of carbon quantum dots, and it summarizes the applications in related fields, such as optoelectronics, bioimaging, drug delivery, cancer therapy, sensors, and environmental remediation. Finally, currently encountered issues of carbon quantum dots are presented. The latest research progress in synthesis and application, as well as the challenges outlined in this review, can help and encourage future research on carbon quantum dots.

Novel Carbon Dots Derived from Moutan Cortex Significantly Improve the Solubility and Bioavailability of Mangiferin

Background

Mangiferin (MA), a bioactive C-glucosyl xanthone with a wide range of interesting therapeutic properties, has recently attracted considerable attention. However, its application in biomedicine is limited by poor solubility and bioavailability. Carbon dots (CDs), novel nanomaterials, have immense promise as carriers for improving the biopharmaceutical properties of active components because of their outstanding characteristics.

Methods

In this study, a novel water-soluble carbon dot (MC-CDs) was prepared for the first time from an aqueous extract of Moutan Cortex Carbonisata, and characterized by various spectroscopies, zeta potential and high-resolution transmission electron microscopy (HRTEM). The toxicity effect was investigated using the CCK-8 assay in vitro. In addition, the potential of MC-CDs as carriers for improving the pharmacokinetic parameters was evaluated in vivo.

Results

The results indicated that MC-CDs with a uniform spherical particle size of 1-5 nm were successfully prepared, which significantly increased the solubility of MA in water. The MC-CDs exhibited low toxicity in HT-22 cells. Most importantly, the MC-CDs effectively affected the pharmacokinetic parameters of MA in normal rats. UPLC-MS analysis indicated that the area under the maximum blood concentration of MA from mangiferin-MC-CDs (MA-MC-CDs) was 1.6-fold higher than that from the MA suspension liquid (MA control) after oral administration at a dose of 20 mg/kg.

Conclusion

Moutan Cortex-derived novel CDs exhibited superior performance in improving the solubility and bioavailability of MA. This study not only opens new possibilities for the future clinical application of MA but also provides evidence for the development of green biological carbon dots as a drug delivery system to improve the biopharmaceutical properties of insoluble drugs.

Rapid Quantitative Detection for Nitrofurantoin Based on Nitrogen-Doped Highly Photoluminescent Carbon Dots

Nitrogen-doped carbon dots (NCD) with high fluorescence retention and good stability were successfully fabricated using citric acid and urea via a facile and eco-friendly one-step microwave method, which exhibited superior specificity for detection of nitrofurantoin (NFT). Upon the addition of NFT, the fluorescence intensity of NCD at 450 nm was significantly decreased. Besides, a satisfactory linear relationship between the fluorescence quenching efficiency and concentrations of NFT was obtained. Especially, NCD was qualitatively and quantitatively applied for detection NFT in milk and meat extract samples with a high recovery rate. Consequently, it was suggested that the detection method had potential application in the specific detection of NFT, offering a novel approach for veterinary drug residue detection.

Targeted Delivery of Sucrose-Coated Nanocarriers with Chemical Cargoes to the Plant Vasculature Enhances Long-Distance Translocation

Current practices for delivering agrochemicals are inefficient, with only a fraction reaching the intended targets in plants. The surfaces of nanocarriers are functionalized with sucrose, enabling rapid and efficient foliar delivery into the plant phloem, a vascular tissue that transports sugars, signaling molecules, and agrochemicals through the whole plant. The chemical affinity of sucrose molecules to sugar membrane transporters on the phloem cells enhances the uptake of sucrose-coated quantum dots (sucQD) and biocompatible carbon dots with β-cyclodextrin molecular baskets (suc-β-CD) that can carry a wide range of agrochemicals. The QD and CD fluorescence emission properties allowed detection and monitoring of rapid translocation (<40 min) in the vasculature of wheat leaves by confocal and epifluorescence microscopy. The suc-β-CDs more than doubled the delivery of chemical cargoes into the leaf vascular tissue. Inductively coupled plasma mass spectrometry (ICP-MS) analysis showed that the fraction of sucQDs loaded into the phloem and transported to roots is over 6.8 times higher than unmodified QDs. The sucrose coating of nanoparticles approach enables unprecedented targeted delivery to roots with ≈70% of phloem-loaded nanoparticles delivered to roots. The use of plant biorecognition molecules mediated delivery provides an efficient approach for guiding nanocarriers containing agrochemicals to the plant vasculature and whole plants.

Sulfuric acid induced-synthesis coupled with ethanol extraction-water precipitation purification method for orange fluorescent carbon dots with dual-emission: Application for methyl blue detection and cell imaging

In this work, by adjusting the sulfuric acid content in reaction solvent of ethanol, orange fluorescent carbon dots (O-FCDs) with dual-emission wavelength and blue fluorescent carbon dots (B-FCDs) with single-emission wavelength were successfully prepared using 1,3-dihydroxynaphthalene as precursor. Coupling with ethanol extraction-water precipitation purification method, pure O-FCDs and B-FCDs with yields of 9.0 % and 21.3 %, quantum yields (QYs) of 43.0 % and 13.7 % were obtained, respectively. The structures and optical properties of O-FCDs and B-FCDs were investigated by TEM, AFM, Raman, FT-IR, XPS, UV-vis, fluorescence analysis etc. The results revealed that sulfuric acid promoted the carbonization and the oxidation of precursor in the reaction process. In comparison with the B-FCDs, O-FCDs showed narrower lattice spacing and band gap, demonstrating the important role of sulfur-doping in fluorescence tuning. Additionally, O-FCDs showed good sensitivity for methyl blue with a linear response range of 0.05-100 μM (LOD was 20 nM) and the satisfactory results were obtained when O-FCDs were applied to the detection of methyl blue in real fish sample. Moreover, two FCDs showed good biocompatibility and negligible cytotoxicity proved by MTT experiment, while, O-FCDs showed better cell imaging effects than that of B-FCDs. Therefore, the O-FCDs had a broad application prospect as sensing platform in detection of methyl blue and for imaging in biological field.

A Review on Low-Dimensional Nanomaterials: Nanofabrication, Characterization and Applications

The development of modern cutting-edge technology relies heavily on the huge success and advancement of nanotechnology, in which nanomaterials and nanostructures provide the indispensable material cornerstone. Owing to their nanoscale dimensions with possible quantum limit, nanomaterials and nanostructures possess a high surface-to-volume ratio, rich surface/interface effects, and distinct physical and chemical properties compared with their bulk counterparts, leading to the remarkably expanded horizons of their applications. Depending on their degree of spatial quantization, low-dimensional nanomaterials are generally categorized into nanoparticles (0D); nanorods, nanowires, and nanobelts (1D); and atomically thin layered materials (2D). This review article provides a comprehensive guide to low-dimensional nanomaterials and nanostructures. It begins with the classification of nanomaterials, followed by an inclusive account of nanofabrication and characterization. Both top-down and bottom-up fabrication approaches are discussed in detail. Next, various significant applications of low-dimensional nanomaterials are discussed, such as photonics, sensors, catalysis, energy storage, diverse coatings, and various bioapplications. This article would serve as a quick and facile guide for scientists and engineers working in the field of nanotechnology and nanomaterials.