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Dopamine (DA) is a potent neuromodulator in the brain that affects a wide range of motivated behaviors. Abnormal concentration of DA is related to a variety of diseases. Hence, it is imperative to establish a rapid and precise method for quantifying DA. In this work, we integrate orange-yellow emissive carbon dots (CDs) with target-induced silver deposition on gold nanoparticles (Au NPs), forming gold/silver core-shell nanoparticles (Au@Ag NPs), to construct a fluorometric and colorimetric dual-signal sensor for sensitive detection of DA. Au NPs and silver ions (Ag+) have minimal effect on the fluorescence of CDs. DA can reduce the silver ions to Ag(0) on the surface of the Au NPs to form a silver shell, resulting in the blue-shift of the absorbance peak from 520 to 416 nm, which overlaps with the excitation spectrum of CDs. As a result, the system color turns from pink to orange-yellow, and the fluorescence of CDs is quenched due to the strong inner filter effect. The linear range of the colorimetry is 0.5–18 μM with a limit of detection (LOD) of 0.41 μM, while the linear range for the fluorometry method is 0.5–14 μM with a LOD of 0.021 μM. This method demonstrates notable advantages including a low detection limit, rapid response time, and straightforward operation in practical samples, showing great potential in biomedical analysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Red emissive fluorescent amphiphilic carbon dots (CL-9) were designed. • The ternary carbon source was used. • CL-9 exerted turn-on red fluorescence towards α-synuclein fibrils. • CL-9 possessed good anti-photobleaching resistance, biocompatibility and high sensitivity. • CL-9 succeeded in imaging α-synuclein fibrils in vivo. The misfolding and aggregation of α -synuclein monomers usually cause the occurrence and development of Parkinson's disease (PD). It is important to develop effective methods for detection of α -synuclein aggregates. Carbon dots (CDs) could be the potential fluorescence probe for this purpose owing to their appreciated optical properties. However, undefined structure of CDs and complicated three-dimensional structure of protein severely hindered the design of fluorescence probe towards protein aggregates. Herein, a red emissive fluorescent amphiphilic CD, named as CL-9, was designed with a high sensitivity to α -synuclein fibrils by a one-step heating process, using the ternary carbon source, including Congo red, l -tryptophan and urea. The CL-9 exhibited turn-on red emissive fluorescence towards α -synuclein fibril, but remained no change towards its monomer. Compared with the original Congo red dye, CL-9 exhibited stronger turn-on red fluorescence towards α -synuclein fibrils with better anti-photobleaching resistance, biocompatibility and signal-to-noise ratio. The CL-9 was successful as a fluorescent probe to image α -synuclein fibrils in NL-5901 C. elegans. The present study provided a feasible approach using the multiple carbon sources to construct the CDs based fluorescence probe targeting amyloid proteins. [ABSTRACT FROM AUTHOR]

[Display omitted] Although photocatalytic H 2 production based on semiconductor materials has a wide potential application, it still facing challenges such as slow reaction kinetics or complex synthesis processes. To meet these challenges, the carbon dots loaded black g-C 3 N 4 (CN-B-CDs) was synthesized by simple calcination method to achieve efficient photothermal-assisted photocatalytic H 2 production. Photothermal imaging experiments confirmed the photothermal effect of CN-B and CDs as dual heat sources to increase the temperature of the composite system, thus improving the effective separation of photo-generated charges. In addition, multiple photocatalytic H 2 production tests exhibited that CN-B-CDs photocatalysts not only have strong stability but also can accommodate a variety of complex water bodies, which displayed the potential for industrial application. This study combined the photothermal effect and the mechanism by which the CDs promote the charge transfer to design a new photocatalytic H 2 production system and provided a new scheme for achieving efficient photothermal-assisted photocatalytic H 2 production using carbon-based materials. [ABSTRACT FROM AUTHOR]

Kojic acid (KA) has gained significant attention due to its widespread use in the food and cosmetics industries. However, concerns about its potential carcinogenic effects have heightened the need for sensitive detection methods. This study introduces a fluorescence-based optical sensor for the quantification of KA in food samples, utilizing fluorescent carbon dots (CDs) synthesized from pomegranate peel via a hydrothermal method. The Stern–Volmer plot demonstrated a linear response for KA in the range of 120 to 1200 µM, with a Pearson correlation coefficient (r) of 0.9999 and. The sensor exhibited a detection limit of 30 ± 0.04 µM and a limit of quantification (LOQ) of 90 ± 0.14 µM. Application of the developed method to soy sauce and vinegar samples yielded accurate KA determinations, with recoveries of 103.11 ± 0.96% and 104.45 ± 2.15%, respectively. These findings highlight the potential of the proposed sensor for practical applications in food quality and safety assessment, offering valuable insights into the presence of KA in food products. [ABSTRACT FROM AUTHOR]

At present, the regulation mechanism of the number and type of amino groups in the precursor and the number of alkyl chains in amine compounds on afterglow performance is not clear. To address this problem, a series of amine compounds as carbon sources is designed and utilized AlPO‐5 zeolite as the matrix to create a range of carbon dots@zeolite composite materials (CDs@AlPO‐5). N heteroatoms not only increase the potential for triplet emission but also introduce more N/O (C═O/C═N/N─H bonds) into the system as the number of amino groups increases. The introduction of abundant active groups and the strong interaction between carbon dots (CDs) and molecular sieve matrix induces a red shift in the afterglow emission wavelength and an increase in lifetime. The quantum yields (QYs) of CDs@AlPO‐5 are affected by the type of amino groups and the number of alkyl chains in the carbon source. The higher activity of the amino reaction site and the reduction in the number of alkyl chains help to regulate the afterglow emission behavior. Intelligent selection of the type and number of amino groups is an important step toward broadening the basis for controllable preparation of highly efficient afterglow materials based on CDs. [ABSTRACT FROM AUTHOR]

Zinc‐based batteries are emerging as the most promising candidates for large‐scale energy storage devices due to their low cost, high safety, and long‐term storage. However, zinc‐based batteries encounter challenges stemming from undesirable side reactions and zinc dendrites on the anode, as well as dissolution on the cathode. Owing to their extremely small size, substantial surface functional groups, and adjustable structure, carbon dots (CDs) present considerable benefits in augmenting coulombic efficiency, expanding cycle life, and enhancing the rate functionality of zinc‐based batteries. Herein, this review delves into the surface modification and morphological regulation of batteries elements by CDs, CDs composites, and CDs derivatives. Moreover, it systematically encapsulates the application of CDs in zinc‐based batteries, underscoring the pivotal role of CDs in the advancement of electrode technology. Finally, the review highlights the impediments and proposes potential avenues for utilizing CDs in zinc‐based batteries. This review aims to facilitate the development of superior solutions and provide scientific insights into energy storage technologies. [ABSTRACT FROM AUTHOR]

Förster resonant energy transfer (FRET) is a well-known and important phenomenon in physics, chemistry, and biology, which plays a crucial role in various photofunctional systems, including photovoltaics, and lighting, and sensing where molecular distances and interactions are probed. This paper presents a systematical investigation of the construction of interfacial FRET between carbon dots (CDs) and NaYF 4 :Eu3+ nanoparticles (NPs) via various synthesis routes. The interfacial FRET was found to take place from CDs to Eu3+ in the wet-mixed and the reacted nanocomposites owing to the presence of strong interfacial interactions, as evidenced by the results of Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). By employing CDs-sensitized NaYF 4 :Eu3+ NPs as a model system, we were able to elucidate the intricate FRET mechanism between CDs and NaYF 4 :Eu3+ NPs. Surprisingly, the reacted nanocomposite exhibits remarkable photo- and thermal-stability, as well as high resistance to thermal degradation, demonstrating the robustness of the interfacial FRET in enhancing Eu3+ emission intensity. The study presents a convenient and versatile approach to achieving interfacial FRET based on CDs nanocomposites, which have a promising potential application in solid-state lighting and biomedicine. [ABSTRACT FROM AUTHOR]

Introduction: The presence of excessive heavy metal content in food poses potential risks to human health. Methods: This paper presents the fabrication of a novel type of Carbon Dots (CDs) using green tea residue as a carbon source, which can be applied for simultaneous detection of Hg2+, Pb2+, Fe3+, and Cu22+ through particle swarm optimization (PSO) based optimized variable-weighted least-squares support vector machine (VWLS-SVM) model and the partial least squares discriminant analysis (PLSDA) method. Results and Discussion: The utilization of PSO-VWLS-SVM model discovered and verified two fluorescence enhancement markers of CDs, namely isoquercitrin and 5-methyl furfural in green tea residues. By employing PLSDA, simultaneous qualitative and quantitative determination of these four metal ions was achieved. These CDs are capable of detecting four types of metal ions at low concentrations even when there are high concentrations of other metal ions and amino acids. More importantly, the CDs were successfully applied for the detection of Hg2+, Pb2+, Fe3+, and Cu2+ in real food samples. The recovery rates of four metal ions spiked into five different matrices were found to be the range of 99.1-101.3%, while both intra-day and inter-day relative standard deviations remained below 0.5% for all samples. This study on chemometrics-assisted exploration into formation mechanisms of endogenous CDs provides theoretical guidance for enhancing their fluorescence properties and expanding their application in heavy metal detection in food. [ABSTRACT FROM AUTHOR]

Aggregation-induced emission (AIE) is a unique phenomenon observed in various materials such as organic luminophores, carbon dots (CDs), organic-inorganic nanocomposites, fluorescent dye molecules, and nanoparticles (NPs). These AIE-active materials, or AIEgens, are ideal for balancing multifunctional phototheranostics and energy dissipation. AIE properties can manifest in organic fluorescent probes, rendering them effective for cancer treatment due to their ability to penetrate deeply and provide high therapeutic efficacy. This efficacy is attributed to their high photobleaching thresholds, ability to induce Stokes shifts, and capacity to activate fluorophores. Therefore, the development of innovative AIE-based materials for disease diagnosis and treatment, particularly for cancer, is both important and promising. Recent years have seen successful demonstrations of nanoparticles with AIE properties being used for photodynamic therapy (PDT) and multimodal imaging of tumor cells. These fluorophores have been shown to impact mitochondria and lysosomes, generate reactive oxygen species (ROS), activate the immune system, load and release drugs, and ultimately induce apoptosis in tumor cells. In this review, we examine previous studies on the manufacturing methods and effects of AIEgens on cancer cells, with a theranostic strategy of simultaneous treatment and imaging. We also investigate the factors affecting drug delivery on different cancer cells, including internal stimuli such as pH, ROS, enzymes, and external stimuli like near-infrared (NIR) light and ultrasound waves. [Display omitted] [ABSTRACT FROM AUTHOR]

Biocompatible Carbon dots (CDs) were obtained by the laser irradiation of vegetable carbon placed in a Phosphate-Buffered Saline (PBS) solution. The carbon nanoparticles were generated by a visible and continuum wave (CW) He-Ne laser beam at a 632.8 nm wavelength with 1 mm2 spot, irradiating the carbon target for times of the order of some hours. The CDs generation might be due to thermal effects induced by the prolonged laser irradiation inducing carbon atoms ejection bounded by weak van de Walls forces. Ultraviolet-visible (UV-Vis) spectroscopy, Fourier-transform infrared spectroscopy (FTIR) transmittance and luminescence measurements were employed to study the CDs synthesize. The UV excitation at a 365 nm wavelength induces visible CDs luminescence mainly at about 474 nm wavelength, giving the emitted light a characteristic blue color. The CDs luminescence in biocompatible solutions is presented and discussed in anticipation of possible applications in various sectors, such as radiation detector and material physics, engineering, microelectronics, sensors and, above all, in relation to bio-images from cell cultures and biological tissue as possible applications to the bio-medical field. [ABSTRACT FROM AUTHOR]

Iodide has long been recognized as an effective shape-directing agent for facilitating the growth of anisotropic noble metal nanostructures. However, little attention has been paid to the specific interaction between iodide and metal nanoparticles. In this study, we demonstrate the selective recognition of iodide in solution by the carbon-dot-gold nanoparticles (Cdot-AuNPs) ensemble. Irregularly-shaped AuNPs were generated through the reduction of HAuCl4 by citrate ions and stabilized by Cdot at ambient temperature. Upon the addition of iodide, the color of the solution changed from blue to red with the growth of AuNPs to semi-spherical nanoparticles, as confirmed by transmission electron microscopy. The selectivity test validated that only iodide could induce this specific visual response, highlighting a novel interaction mechanism between iodide and AuNPs. The recognition of iodide by this Cdot-AuNPs ensemble showed good resistance toward many environmentally relevant metal ions, particularly Ca2+, providing potential for the identification of iodide ions in real samples. Mixing tetrachloroauric acid, sodium citrate, and bee pollen-derived carbon dots (Cdot) at ambient temperature leads to the preparation of Cdot-AuNPs ensemble for the specific colorimetric recognition of iodide by reshaping the dimensions of the AuNPs. [ABSTRACT FROM AUTHOR]

The enzyme-mimicking nature of versatile nanomaterials proposes a new class of materials categorized as nano-enzymes, ornanozymes. They are artificial enzymes fabricated by functionalizing nanomaterials to generate active sites that can mimic enzyme-like functions. Materials extend from metals and oxides to inorganic nanoparticles possessing intrinsic enzyme-like properties. High cost, low stability, difficulty in separation, reusability, and storage issues of natural enzymes can be well addressed by nanozymes. Since 2007, more than 100 nanozymes have been reported that mimic enzymes like peroxidase, oxidase, catalase, protease, nuclease, hydrolase, superoxide dismutase, etc. In addition, several nanozymes can also exhibit multi-enzyme properties. Vast applications have been reported by exploiting the chemical, optical, and physiochemical properties offered by nanozymes. This review focuses on the reported nanozymes fabricated from a variety of materials along with their enzyme-mimicking activity involving tuning of materials such as metal nanoparticles (NPs), metal-oxide NPs, metal–organic framework (MOF), covalent organic framework (COF), and carbon-based NPs. Furthermore, diverse applications of nanozymes in biomedical research are discussed in detail. [ABSTRACT FROM AUTHOR]

Background: Ulcerative colitis (UC) is a chronic intestinal inflammation, resulting in a global healthcare challenge with no real specific medicine. Natural medicines are recognized as a potential clinical alternative therapy, but their applications are limited by poor solubility and low bioavailability. Results: In this work, inspired by the natural medicines of ancient China, novel functional carbon dots derived from Magnetite and Medicated Leaven (MML-CDs) were synthesized by hydrothermal method, and confirmed their ultrasmall nano-size (3.2 ± 0.6 nm) and Fe doped surface structure, thereby with excellent gastrointestinal stability, remarkable capabilities in eliminating ROS, and highly biocompatibility. With no external stimuli, the oral administration of MML-CDs demonstrated obvious alleviation to UC. Further experiments pointed that MML-CDs could improve hemostasis capability, suppress inflammation reactions and oxidative stress, and up-regulate the expression of tight junction proteins. Furthermore, MML-CDs also showed well regulation in the dysbiosis of intestinal flora. Conclusion: Overall, above evidence reveals that green-synthesized MML-CDs can significantly alleviate intestinal bleeding, inhibit colon inflammation, and repair colonic barrier damage, further regulating intestinal flora and intestinal inflammation microenvironment. Our findings provide an efficient oral administration of MML-CDs as a novel therapy strategy for ulcerative colitis. [ABSTRACT FROM AUTHOR]

Photodynamic therapy (PDT) has long been considered an effective way to tackle antibiotic resistance. Here, Methylene blue (MB) as photosensitizer was combined with carbon quantum dots (CQDs) as drug carriers to make a compound antibacterial agent. The fluorescent CQDs were prepared by hydrothermal method with citric acid (CA) and neutral red (NR) as raw materials. The CQDs can emit 640nm red fluorescence under 520nm laser irradiation. In the antibacterial experiment, CQDs-MB was irradiated with 660nm light. The results showed that CQDs-MB had ideal antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) with 100% antibacterial concentration of 5μM and 10μM, respectively. The combination of CQDs and MB enhanced singlet oxygen (1O2) generation and the PDT activity of MB, which significantly increased the phototoxicity of MB to bacteria. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) have attracted much attention in the field of electrocatalysis due to their many advantages. These reactions are of great significance for energy conversion and storage, as well as environmental remediation. In this review, we summarize the latest achievements in the electrochemical applications of CDs and their composites, with a focus on environmentally relevant electrocatalysis. We present some representative examples of CDs‐based electrocatalysts for different reactions and analyze the catalytic mechanisms and the factors that affect the electrocatalytic performance. Furthermore, we conclude with some challenging issues and future perspectives of this emerging material. This review aims to help readers better understand the application of CDs in the field of electrocatalysis, reveal the reasons that affect electrocatalytic performance, and guide further constructing more efficient, stable, and green electrocatalysts. [ABSTRACT FROM AUTHOR]

Comprehensive Summary Chiral phosphorescent materials have received extensive research owing to the unique properties of optical activity in recent years. Many phosphorescent carbon dots (CDs) materials have been reported, but the research on chiral phosphorescence is still in the exploratory stage. This work designs multi‐color room temperature phosphorescent (RTP) CDs with chiral signals, which are fully mixed with aromatic aldehyde precursors and chiral amino compounds precursors in a boric acid (BA) matrix and can be easily prepared by solvent‐free thermal method. The prepared (R)‐GCDs, (R)‐YCDs and (R)‐RCDs achieved phosphorescence emission at 545 nm, 582 nm, and 654 nm, respectively, and exhibited corresponding circular dichroism (CD) signals at 341 nm, 394 nm, 384 nm, and 380 nm, 448 nm, and 435 nm, respectively. The longest phosphorescence lifetime is up to 946 ms. Specifically, YCDs exhibit time‐dependent phosphorescence under UV excitation, and the afterglow time under white light excitation can reach 40 s. This article provides a new approach to the study of chiral phosphorescence. [ABSTRACT FROM AUTHOR]

Room temperature phosphorescence carbon dots (RTP CDs) are one of the newly investigated nanomaterials because of their remarkable optical characteristics. They are widely utilized in many versatile optoelectronic and security applications. Apart from synthesis, one of its challenging attributes is its lifetime at room temperature. Here, a straightforward and quick heating approach is presented for synthesizing self‐matrix 1,10 phenanthroline and boron‐based RTP CDs. 1,10 phenanthroline is utilized as an aromatic and hetero atom containing carbon precursor and boric acid is used as a passivating to stabilize the triplet excitons and prevent nonradiative deactivation. Various characterization techniques like TEM, XRD, FTIR, UV–vis, PL, and elemental analysis (ICP and CHNS) have been used to study the properties of self‐matrix RTP CDs. The RTP CDs exhibited excellent blue‐green emission when excited at 302 nm. Compared to the available literature, the novelty of this work is observed from its high naked eye phosphorescence characteristic of ≈22 s with an average lifetime of ≈ 2.4 s at 302 nm, making them ultralong self‐matrix RTP CD material. Due to their exceptional qualities, the self‐matrix RTP CDs have been widely employed for various applications, including information encryption decryption, phosphor for LEDs, anticounterfeiting, and water sensitivity analysis. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) have garnered extensive attention owing to their excellent biocompatibility, elevated specific surface area, and facile functionalization, as well as their diverse methods of preparation. In recent times, CDs have been applied for anti‐corrosion and obtained some significant results. In this work, the preparation methods of CDs are first briefly introduced, and the relative merits of different approaches are highlighted. Subsequently, the application of CDs in the realm of corrosion inhibitors is discussed, and the corrosion inhibition effects and mechanism of nitrogen‐doped CDs, nitrogen and sulfur‐co‐doped CDs, as well as CDs functionalized with other elements and nitrogen‐co‐doped are summarized. Finally, the application of CDs and functionalized CD‐modified coatings for anti‐corrosion and their protective mechanism is analyzed in detail. This review summarizes recent progress in research related to CDs and heteroatom‐doped CDs in anti‐corrosion applications and anticipates the prospects and applications of CDs in corrosion protection. With their unique properties and versatile applications, CDs are expected to assume a progressively pivotal role in the advancement of cutting‐edge corrosion protection technologies. [ABSTRACT FROM AUTHOR]

Hydrothermal carbonization (HTC) stands out as an eco-friendly, cost-effective method for generating renewable carbon-based materials from biomass. The HTC process yields products such as hydrochars and carbon dots (CDs), possessed of notable photocatalytic capabilities due to their unique physicochemical features. Additionally, pairing traditional photocatalysts with hydrochar derivatives elevates their performance, rendering them more effective. Recent times have witnessed a surge in interest in these hydrochar based photocatalysts (HC-photocatalysts). Their appeal stems from multiple attributes: impeccable performance, adaptability to visible light, and adjustable physicochemical properties. This review delves deep into the evolving landscape of these HC-photocatalysts, segmenting them into three distinct categories: hydrochars, hydrochar-based CDs (HC-CDs), and hydrochar-based composites (HC-composites). For each category, we dissect their synthesis routes, unravel the photocatalytic mechanisms, and explore various enhancement strategies. We further traverse their versatile applications, spanning environmental treatment, disinfection, energy conversion, and organic synthesis. In the end, we spotlight the prevailing challenges and uncharted territories in the domain of HC-photocatalysts. In essence, this review serves as a guide, furnishing a theoretical foundation and steering directions for future explorations and tangible implementations of HC-photocatalysts. Highlights: Biomass can be converted into highly efficient photocatalysts by HTC. Photocatalytic mechanisms and modifications of hydrochars and HC-CDs are discussed. The roles of carbons in HC-composite photocatalysts are reviewed. HC-photocatalysts have shown various environmental, energy and other applications. Prospects and guidelines for theoretical and application research are listed. [ABSTRACT FROM AUTHOR]

Nanomedicines loaded in macrophages (MAs) can actively target tumors without dominantly relying on the enhanced permeability and retention (EPR) effect, making them effective for treating EPR‐deficient malignancies. Herein, copper‐crosslinked carbon dot clusters (CDCs) are synthesized with both photodynamic and chemodynamic functions to manipulate MAs, aiming to direct the MA‐mediated tumor targeting. First, green fluorescent CDs (g‐CDs) are prepared by a one‐step hydrothermal method. Subsequently, the g‐CDs are complexed with divalent copper ions to form copper‐crosslinked CDCs (g‐CDCs/Cu), which are incubated with MAs for their manipulation. Experimental results revealed that the prepared g‐CDCs/Cu displayed good aqueous dispersibility and fluorescent emission properties. The nanoassemblies can be activated to deplete the overexpressed glutathione (GSH) and generate reactive oxygen species (ROS) in the presence of laser irradiation through the combined Cu‐mediated chemodynamic therapy and CD‐mediated photodynamic therapy. Furthermore, the ROS produced in MAs enabled polarization of MAs to antitumor M1 phenotype, suggesting the future potential use to reverse the immunosuppressive tumor microenvironment. These results obtained from the current study suggest a significant potential to develop g‐CDCs/Cu for GSH depletion, ROS generation, and MA M1 polarization as a theransotic agent to tackle cancer. [ABSTRACT FROM AUTHOR]

Targeted fluorescence probes for imaging and differentiation of hepatocellular carcinoma (HCC) are highly desirable from its scientific research and clinical applications. However, most of the current targeted fluorescence probes focus on the variation of intracellular microenvironment caused by the cancerization of hepatocyte, which causes a fluorescence intensity alteration but fails to produce a spatial differentiation due to the lack of robust parameters for further improving accuracy. Herein, the study develops a new fluorescent carbon dot (CTF‐CDs) that can target the overexpressed GABAA receptor (GABAAR) on cell membrane for accurate and high‐contrast imaging of HCC and differentiation. The competition response between CTF‐CDs and typical receptor‐binding ligands reveals their affinity toward the picrotoxin‐binding site of GABAAR. Based on this GABAAR‐targeting ability, accurate imaging of HCC cells is realized by lighting their membranes, along with a big difference from the intracellular fluorescence of normal liver cells and other cancer cells. In addition, the CTF‐CDs have also been used to visualize the anticancer drug‐induced variations on HCC cell membrane and fluorescent imaging in HCC tissue. This work extends the targeting object of fluorescence probes from intracellular microenvironment to membrane protein, adding a new dimension to the imaging and differentiation of HCC. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide(MoS2) has a special structure and excellent mechanical properties, making it a promising reinforcing filler for polymers. Carbon dots (CDs) have good antioxidant properties, and the addition of CDs during the synthesis of MoS2 can affect its morphology and size. In this work, a new one-step hydrothermal synthesis process was employed to prepare CDs/MoS2 hybrid particles. Thiourea, sodium molybdate, and glucose were employed as sources of sulfur, molybdenum, and carbon, respectively. The structure and morphology of MoS2 and CDs/MoS2 were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), mapping surface scanning (SEM–EDS), and Fourier transform infrared spectroscopy (FTIR). The results show that the prepared 2H-MoS2 is stacked into flower-like spheres with size around 2–10 μm; with the formation of CDs, the size of MoS2 rapidly decreases to less than 1 μm and the CDs are evenly distributed on its surface with mass ratio of 40.2% (CDs in CDs/MoS2). Subsequently, the CDs/MoS2 were used as reinforcing fillers for natural rubber (NR) latex. The results of mechanical properties show that tear strength, tensile strength, modulus, and elongation at break are increased by the addition of CDs/MoS2 in a very lower loading, and the maximum increment ratio is 45.6% and 12.1% when compared to NR-0; the dynamic mechanical analysis and cross-link density results indicated that the CDs/MoS2 can simultaneously improve rigidity and elasticity of NR. The thermal stability results suggest that the CDs/MoS2 shows positive effects on thermal stability of NR. [ABSTRACT FROM AUTHOR]

[Display omitted] • 1. AFM-based biophysical measurements are performed on a neural cell. • 2. Exposure to high-dose carbon dots affects cellular mechanics and morphology. • 3. Actin filaments are disorganized in the cells after exposure to high-dose carbon dots. • 4. Biological studies validate the cytotoxic effects disclosed by AFM. • 5. AFM is a powerful biophysical tool for the study of cell-nanomaterials interactions. Understanding the cytotoxicity of fluorescent carbon dots (CDs) is crucial for their applications, and various biochemical assays have been used to study the effects of CDs on cells. Knowledge on the effects of CDs from a biophysical perspective is integral to the recognition of their cytotoxicity, however the related information is very limited. Here, we report that atomic force microscopy (AFM) can be used as an effective tool for studying the effects of CDs on cells from the biophysical perspective. We achieve this by integrating AFM-based nanomechanics with AFM-based imaging. We demonstrate the performance of this method by measuring the influence of CDs on living human neuroblastoma (SH-SY5Y) cells at the single-cell level. We find that high-dose CDs can mechanically induce elevated normalized hysteresis (energy dissipation during the cell deformation) and structurally impair actin skeleton. The nanomechanical change highly correlates with the alteration of actin filaments, indicating that CDs-induced changes in SH-SY5Y cells are revealed in-depth from the AFM-based biophysical aspect. We validate the reliability of the biophysical observations using conventional biological methods including cell viability test, fluorescent microscopy, and western blot assay. Our work contributes new and significant information on the cytotoxicity of CDs from the biophysical perspective. [ABSTRACT FROM AUTHOR]

[Display omitted] Tumor metastasis and recurrence are closely related to immune escape and hypoxia. Chemodynamic therapy (CDT), photodynamic therapy (PDT), and photothermal therapy (PTT) can induce immunogenic cell death (ICD), and their combination with immune checkpoint agents is a promising therapeutic strategy. Iron based nanomaterials have received more and more attention, but their low Fenton reaction efficiency has hindered their clinical application. In this study, Fe 3 O 4 -carbon dots complex (Fe 3 O 4 -CDs) was synthesized, which was modified with ferrocenedicarboxylic acid by amide bond, and crosslinked into Fe 3 O 4 -CDs@Fc nano complex. The CDs catalyzed the Fenton reaction activity of Fe 3 O 4 by helping to improve the electron transfer efficiency, extended the reaction pH condition to 7.4. The Fe 3 O 4 -CDs@Fc exhibit exceptional optical activity, achieving a thermal conversion efficiency of 56.43 % under 808 nm light and a photosensitive single-line state oxygen quantum yield of 33 % under 660 nm light. Fe 3 O 4 -CDs@Fc improved intracellular oxygen level and inhibited hypoxia-inducing factor (HIF-1 α) by in-situ oxygen production based on Fenton reaction. The multimodal combination of Fe 3 O 4 -CDs@Fc (CDT/PDT/PTT) strongly induced immune cell death (ICD). The expression of immune-related protein and HIF-1 α was investigated by immunofluorescence method. In vivo, Fe 3 O 4 -CDs@Fc combined with immune checkpoint blocker (antibody PD-L1, αPD-L1) effectively ablated primary tumors and inhibited distal tumor growth. Fe 3 O 4 -CDs@Fc is a promising immune-antitumor drug. [ABSTRACT FROM AUTHOR]

Polylysine-modified near-infrared (NIR)-emitting CDs assemblies (plys-CDs) were synthesized through post-solvothermal reaction of NIR-emitting CDs with polylysine. The obtained plys-CDs not only inherit the superior photothermal conversion efficiency of up to 54.9 %, but also exhibit significantly enhanced NIR fluorescence emission. Due to the increased particle size of about 40 ± 8 nm, plys-CDs exhibit enhanced the efficacy of tumor accumulation via intravenous injection, leading to improved performance in tumor photothermal therapy. [Display omitted] A key challenge to enhance the therapeutic outcome of photothermal therapy (PTT) is to improve the efficiency of passive targeted accumulation of photothermal agents at tumor sites. Carbon dots (CDs) are an ideal choice for application as photothermal agents because of their advantages such as adjustable fluorescence, high photothermal conversion efficiency, and excellent biocompatibility. Here, we synthesized polylysine-modified near-infrared (NIR)-emitting CDs assemblies (plys-CDs) through post-solvothermal reaction of NIR-emitting CDs with polylysine. The encapsulated structure of plys-CDs was confirmed by determining morphological, chemical, and luminescent properties. The particle size of CDs increased to approximately 40 ± 8 nm after polylysine modification and was within the size range appropriate for achieving superior enhanced permeability and retention effect. Plys-CDs maintained a high photothermal conversion efficiency of 54.9 %, coupled with increased tumor site accumulation, leading to a high efficacy in tumor PTT. Thus, plys-CDs have a great potential for application in photothermal ablation therapy of tumors. [ABSTRACT FROM AUTHOR]

Lanthanide ions-doped fluoride nanocrystals have excellent application prospect. However, low photoluminescence quantum yield (PLQY) is usually along with lanthanide ions-doped fluoride nanocrystals owing to their low molar absorptivity and narrow absorption band. In order to increase the absorption cross section of Ln3+ in fluoride nanocrystals, a facile synthesis strategy to enhance luminescence of AF 2 : Ln3+ (A = Ca, Sr; Ln = Eu, Tb) by the use of carbon dots (CDs) has been developed in this work. A series of characterizations including TEM, XRD, FTIR and XPS demonstrated that the CDs have been successfully combined with the surface of AF 2 : Ln3+ nanocrystals. The combination of CDs has little influence on the microstructure and phase structure of AF 2 : Ln3+, and CDs@AF 2 : Ln3+ nanocrystals have uniform and regular shape with cubic phase. CDs are used as a broadband sensitizer and lead to the broadband excitation of Ln3+, resulting in the enhancement around 10-fold of Ln3+ luminescence emission in AF 2 : Ln3+ nanocrystals after CDs combination. The corresponding PLQY increases almost three times, and the luminescence enhancement mechanism by combining CDs is proposed. In addition, the CDs@AF 2 : Ln3+ nanocrystals are used to prepare CDs@AF 2 : Ln3+/PVA films, which exhibits excellent luminescence properties under the excitation of UV light. This work provides a superior method for enhancing the luminescence properties of lanthanide ions-doped nanocomposites and demonstrates practical potential as promising candidates for light-converting thin films. [Display omitted] • CDs can be as a broadband sensitizer to increase the absorption cross section of Ln3+ in AF 2 : Ln3+ nanocrystals. • The fluorescence emission of AF 2 : Ln3+ (A = Ca, Sr; Ln = Eu, Tb) increases by about 10 times by combining CDs. • CDs are able to capture the electrons of Ln3+ and transfer energy to Ln3+ in AF 2 : Ln3+ nanocrystals. • CDs@AF 2 : Eu3+/PVA film can be fabricated and converts UV to red light. [ABSTRACT FROM AUTHOR]

Carbon Quantum Dots (CQDs) are nanoscale carbon‐based particles with unique quantum properties. Because of their customizable size, optical properties, and surface functions, CQDs are frequently used in a wide range of applications. The present thorough analysis delves into the crucial function of CQDs in the photocatalytic breakdown of Methylene Blue (MB), providing valuable perspectives on their production, attributes, and catalytic processes. The effects of pH, wavelength, intensity, and other variables on the effectiveness of MB degradation are covered in detail. An analytical review of the kinetic models used to estimate the deterioration process is given. For improved stability and recyclability, the synergistic effects of CQD‐based composites and developments in catalyst immobilization techniques are examined. Prospects for the future center on reactor designs, integration into large‐scale water treatment systems, and optimization of CQD features. The research highlights the revolutionary potential of CQDs in transforming wastewater treatment and advancing environmentally sound solutions. [ABSTRACT FROM AUTHOR]

This study vividly demonstrates the formation of a fluorescence-based temperature-sensing thermometer, obtained from a nanohybrid material, composed of self-assembled peptide-appended core-substituted naphthalenediimide and carbon nanodots. The nanohybrid system can exhibit variable fluorescence output depending on the changes in the temperature within a wide range of −25 to 90 °C. This two-component optically active hybrid material has been designed and constructed from cyan-emitting carbon dots (C-dots) and a red-emitting π-conjugated peptide-appended naphthalenediimide-based molecule (c-NDI-P) in ortho-xylene at room temperature (25 °C). At very low temperatures (−25 °C), the system emits a blue color, while at high temperatures (90 °C), the emission is reddish pink. If the temperature is around −3 °C, the system exhibits cyan emission, and at room temperature (25 °C), a white-colored emission is obtained. Förster resonance energy transfer (FRET) from the donor C-dots to the acceptor c-NDI-P is responsible for the white light emission. This is a unique example of a two-component fluorescent nanoscale thermometry system that exhibits a blue to cyan to reddish pink emissive color passing through a white light at room temperature (25 °C). [ABSTRACT FROM AUTHOR]

Although possessing well‐defined nanostructures and excellent multi‐electron redox properties, polyoxometalate clusters have poor intrinsic electrical conductivity and are prone to aggregation due to large surface energy, which makes them difficult to be fully utilized when applying as electrode materials for lithium‐ion batteries. In this paper, monodisperse K7MnV13O38 (MnV13) clusters are achieved by rationally utilizing nano‐sized high conductive carbon dots (CDs) as stabilizers. Benefiting from the fully exposed redox sites of MnV13 clusters (high utilization rate) and sufficient interfaces with carbon dots (extra interfacial energy storage), the optimized MnV13/10CDs anode delivers a high discharge capacity up to 1348 mAh g−1 at a current density of 0.1 A g−1 and exhibits superb rate/cycling capabilities. Density functional theory (DFT) calculations verify that ionic archway channels are formed between MnV13 and CDs, eliminating the bandgap and greatly improving the electron/ion conductivity of MnV13 and CDs. This paper paves a brand‐new way for synthesis of monodisperse clusters and maximization of extra interfacial energy storage. [ABSTRACT FROM AUTHOR]

Constrained by a limited understanding of the structure and luminescence mechanisms of carbon dots (CDs), achieving precise enhancement of their photoluminescence (PL) performance without altering the emission wavelength and color remains a challenge. In this work, a deuterated CD is first achieved by simply replacing the reaction solvent from H2O to D2O. The substitution of D atoms for H atoms is not limited on the surface but also within the internal structure of CDs. Deuteration affects the formation of the π‐conjugated network structure by altering the content of sp2 carbon and sp3 carbon, ultimately inducing a reconstruction for energy level structure of CDs. Both the intrinsic state and surface state emission, including quantum yield, emission intensity and lifetime, are significantly enhanced after deuteration. It benefits from the reduction in non‐radiative transitions, since the lowered vibrational frequencies of D atoms and optimized local energy level distribution in CDs structure. The deuterated CDs are applied in the fabrication of white‐light‐emitting diodes to show their application potential. This work provides a highly versatile route for improving and controlling photoluminescence performance of CDs and has opportunities to guide the development of CDs for practical applications. [ABSTRACT FROM AUTHOR]

Cuprous ions (Cu+) are essential for various biological activities. However, it is still a great challenge to detect Cu+ efficiently in cells in situ. As emerging 0‐D carbon photoluminescence nanomaterials, carbon dots (CDs) exhibit non‐toxicity and ultra stability, which shows great advantages in biosensing and bioimaging. In this work, CDs are prepared by a one‐step microwave‐assisted hydrothermal method. To enhance the selectivity and efficiency of the CDs‐based sensor, the NS4‐CDs are synthesized by surface modification of CDs using Cu+ chelating molecules. The NS4‐CDs, that carry specific detection molecules, exhibit remarkable selectivity and high sensitivity with an extraordinarily low detection limit (26 nmol L−1). It is noteworthy that the detection response is extremely fast, which only takes 20 s. The PL response mechanism of NS4‐CDs is also thoroughly investigated. In addition, the NS4‐CDs possess great biocompatibility and non‐cytotoxicity, which is vital for advanced cellular imaging applications. Finally, the NS4‐CDs are successfully applied to Cu+ detection in cells in situ. This work paves a new path for the design and efficient construction of CDs‐based biosensors for ion detection in cells, which expands the application area of carbon nanomaterials. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs) are in great demand in many fields because of their unique properties such as high conductivity, chemical stability, lightweight, and high strength. They also received much attention in optical‐related fields because of the super‐black characteristics under visible light and the photothermal effect of infrared light. Recently, the coloration of CNTs under visible light is realized by a simple liquid phase method with the help of silica photonic crystal (PC) coatings. However, the response modulation such as the photoluminescence (PL) property of CNTs to the infrared and ultraviolet (UV) bands is not yet studied. Herein, silane functionalized carbon dots (SiCDs) are introduced into silica PCs, and successfully realized the structural coloration and PL of CNT fibers (CNTFs). The optical and fluorescence visualization of single CNTs and suspended CNT networks (SCNTNs) is also realized with the assistance of SiCDs droplets. These SiCDs‐decorated SiPCs‐coated CNTFs (SiCDs@SiPCs‐CNTFs) exhibit an up/down‐conversion PL response, and the excitation light source can be UV light, visible light, and near‐infrared laser. The structural coloration and the development of new PL properties will promote the wide applications of PL carbon hybrid materials in many fields such as smart displays, intelligent textiles, anti‐counterfeiting, etc. [ABSTRACT FROM AUTHOR]

Carbon is one of the most abundant minerals in the universe. The world’s energy needs are being unmet due to the exponential rise in population. Since its inception 20 years ago, carbon and its allotropes, including fullerenes, carbon nanotubes, and graphene, have been marketed as potential energy storage and generation materials. By solving important issues like accumulation and inadequate thermodynamic compatibility, carbon fiber, expanded graphite, and carbon nanotubes are promising functional materials that can be used to improve the performance of bipolar plates further. There are several potential uses for carbon-based nanomaterials (CBNMs) in the energy area. This mini-review provides an overview of the synthetic routes employed for producing CBNMs, categorizing them based on their types, elucidating their diverse applications in fuel energy systems, and emphasising the uses of CBNMs in energy. The advantages and disadvantages of several synthetic processes have been examined and compared. The types of CBNMs, like carbon nanotubes, graphene, carbon dots, and fullerenes, are explored in terms of their unique structural properties and fabrication methods. Furthermore, the utilization of CBNMs in fuel energy systems, such as fuel cells, energy storage devices, and catalysis, is comprehensively reviewed. [ABSTRACT FROM AUTHOR]

Hydrogen, as a perfect energy carrier, has the characteristics of high energy density and harmless combustion products, and become a clean energy to answer the energy disaster and reduce carbon emissions. Among the current methods of hydrogen production, electrocatalytic technology combined with renewable energy is an important development direction of sustainable energy supply. However, it is limited by low energy conversion efficiency and the need for expensive electrocatalysts in the actual production process. In this background, carbon-based nanocomposites become a hot research direction, as a hopeful alternative to the noble metal catalysts currently used. As a member of the family of carbon-based nanomaterials, carbon dots (CDs) have attracted more and more attention owing to their advantages of large specific surface area, low in price, innocuity, high conductivity and abundant functional groups on the surface. CDs have been used in the field of electrocatalysis in hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) as functional materials. The review focuses on the latest research progress in the application of CDs-based composites in HER and OER. The preparation methods of CDs and CDs-based composites, the advantages of CDs in electrocatalytic applications, and the problems faced in the advance of CDs-based composites are discussed. The review hopes to offer some visions into the recent challenges and research directions in the future for this field based on the perspective of CDs. • The properties of CDs, especially their electrocatalytic behavior, are introduced. • The recent advances of CDs as electrocatalyst for HER and OER are discussed. • The current challenges and prospects for CDs in electrocatalytic are proposed. [ABSTRACT FROM AUTHOR]

The hybrid material was obtained from the synthesis of graphene oxide (GO) followed by GO chemical reduction with L‐ascorbic acid. Then hydrothermal synthesis was carried out to form and grow carbon dots (CDs) on the surface of reduced graphene oxide (rGO). The material obtained, CD@rGO, was characterized by transmission electron microscopy (TEM), the infrared (FTIR), Raman and UV‐visible (UV‐Vis) spectroscopy, in addition to X‐ray diffractometry (XRD), spectroscopy and electrochemical methods. The results indicated the formation of carbon dots on the surface of rGO. The study of the voltammetric determination of hydroxychloroquine (HCQ) was performed using adsorptive stripping voltammetry (AdSV) and employing a modified electrode with CD@rGO (ECR). Optimizations were kept in the electrolytic environment and AdSV technique parameters, making it possible to obtain a LOD and LOQ of 2.40 and 7.99 pmol L−1, respectively. The evaluation of the ECR electrochemical stability, repeatability and reproducibility tests were performed with maximum variations of up to 2.79 and 2.03 %, respectively. Determinations in commercial samples of HCQ (tablets) and synthetic urine, recovery in the range of 101.55–106.83 % were obtained. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) obtained from 5‐(hydroxymethyl)furfural (5‐HMF) were activated by a 365 nm‐UV irradiation source and employed in the Knoevenagel condensation to investigate their photocatalytic mechanism. To this end, electrospray ionization mass spectrometry (ESI‐MS) was used to monitor the time progress of the condensation and follow the formation of the final product in positive and negative ion modes at once. The intervention of the superoxide radical anion in the photocatalytic mechanism of CDs was highlighted. [ABSTRACT FROM AUTHOR]

We predicted the protein therapeutic targets specific to a Ru-based potential drug and its combination with pristine and N-doped carbon dot drug delivery systems, denoted as RuCN/CDs and RuCN/N-CDs. Synchrotron-based FTIR microspectroscopy (µFTIR) in addition to bioinformatics data on drug structures and protein sequences were applied to assess changes in the protein secondary structure of A2780 cancer cells. µFTIR revealed the moieties of the target proteins' secondary structure changes only after the treatment with RuCN and RuCN/N-CDs. A higher content of α-helices and a lower content of β-sheets appeared in A2780 cells after RuCN treatment. Treatment with RuCN/N-CDs caused a substantial increase in parallel β-sheet numbers, random coil content, and tyrosine residue numbers. The results obtained suggest that the mitochondrion-related proteins NDUFA1 and NDUFB5 are affected by RuCN either via overexpression or stabilisation of helical structures. RuCN/N-CDs either induce overexpression of the β-sheet-rich protein NDUFS1 and affect its random coil structure or interact and stabilise its structure via hydrogen bonding between -NH2 groups from N-CDs with protein C=O groups and –OH groups of serine, threonine, and tyrosine residues. The N-CD nanocarrier tunes this drug's action by directing it toward a specific protein target, changing this drug's coordination ability and inducing changes in the protein's secondary structures and function. [ABSTRACT FROM AUTHOR]

Heterogeneity in the fluorescence of carbon dots (CDs) has been hard to figure out so far. This could potentially be related to structural factors, size or intermediate fluorophores, especially when employing the bottom‐up synthesis. Herein, we unveil the origin of fluorescence and spectral heterogeneity of CDs using a simple dynamic method. This work reports the room light‐excited green fluorescence and dual‐emissive N‐doped CDs synthesized using a hydrothermal method. Studies were carried out considering the factors of fluorescence phenomena, such as excitation‐independent emission, fluorescent impurities, aggregation and solvation dynamics. The new steady‐state, Excitation‐resolved area‐normalized emission spectroscopy (ERANES) and ensemble measurements, including time‐resolved studies reveal that a heterogeneous environment exists in the ground state. Eventually, the results show the existence of core, edge and surface states in the CDs. Additionally, the fluorescence characteristics depend on the structural functionalization that occurs in both the intrinsic and extrinsic states of the CDs and it is proven that this does not violate the Kasha‐Vavilov rule. Although a highly purified material could still exhibit heterogeneity due to the ensemble emissive states and structural variations. Our results provide insights into the enduring debates about fluorescence and a deeper understanding of the structure‐ property relationship of CDs. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance (AMR) presents an escalating global challenge as conventional antibiotic treatments become less effective. In response, photodynamic therapy (PDT) and photothermal therapy (PTT) have emerged as promising alternatives. While rooted in ancient practices, these methods have evolved with modern innovations, particularly through the integration of lasers, refining their efficacy. PDT harnesses photosensitizers to generate reactive oxygen species (ROS), which are detrimental to microbial cells, whereas PTT relies on heat to induce cellular damage. The key to their effectiveness lies in the utilization of photosensitizers, especially when integrated into nano- or micron-scale supports, which amplify ROS production and enhance antimicrobial activity. Over the last decade, carbon dots (CDs) have emerged as a highly promising nanomaterial, attracting increasing attention owing to their distinctive properties and versatile applications, including PDT and PTT. They can not only function as photosensitizers, but also synergistically combine with other photosensitizers to enhance overall efficacy. This review explores the recent advancements in CDs, underscoring their significance and potential in reshaping advanced antimicrobial therapeutics. [ABSTRACT FROM AUTHOR]

The development of portable and efficient nanoprobes to realize the quantitative/qualitative onsite determination of food pollutants is of immense importance for safeguarding human health and food safety. With the advent of the smartphone, the digital imaging property causes it to be an ideal diagnostic substrate to point-of-care analysis probes. Besides, merging the versatility of carbon dots nanostructures and bioreceptor abilities has opened an innovative assortment of construction blocks to design advanced nanoprobes or improving those existing ones. On this ground, massive endeavors have been made to combine mobile phones with smart nanomaterials to produce portable (bio)sensors in a reliable, low cost, rapid, and even facile-to-implement area with inadequate resources. Herein, this work outlines the latest advancement of carbon dots nanostructures on smartphone for onsite detecting of agri-food pollutants. Particularly, we afford a summary of numerous approaches applied for target molecule diagnosis (pesticides, mycotoxins, pathogens, antibiotics, and metal ions), for instance microscopic imaging, fluorescence, colorimetric, and electrochemical techniques. Authors tried to list those scaffolds that are well-recognized in complex media or those using novel constructions/techniques. Lastly, we also point out some challenges and appealing prospects related to the enhancement of high-efficiency smartphone based carbon dots systems. [ABSTRACT FROM AUTHOR]

A novel and sensitive fluorescence ratiometric method is developed for urea detection based on the pH-sensitive response of two fluorescent carbon dot (CD) systems: R-CDs/methyl red (MR) and NIR-CDs/Cu2+. The sensing mechanism involves breaking down urea using the enzyme urease, releasing ammonia and increasing pH. At higher pH, the fluorescence of NIR-CDs is quenched due to the enhanced interaction with Cu2+, while the fluorescence of R-CDs is restored as the acidic MR converts to its basic form, removing the inner filter effect. The ratiometric signal (F608/F750) of the R-CDs/MR and NIR-CDs/Cu2+ intensities changed in response to the pH induced by urea hydrolysis, enabling selective and sensitive urea detection. Detailed spectroscopic and morphological investigations confirmed the fluorescence probe design and elucidated the sensing mechanism. The method exhibited excellent sensitivity (0.00028 mM LOD) and linearity range (0.001 – 8.0 mM) for urea detection, with successful application in milk samples for monitoring adulteration, demonstrating negligible interference and high recovery levels (96.5% to 101.0%). This ratiometric fluorescence approach offers a robust strategy for selective urea sensing in complicated matrices. [ABSTRACT FROM AUTHOR]

A novel and simple ratiometric fluorescent aptasensor was developed for the sensitive detection of aflatoxin B1 (AFB1). A hairpin DNA (h-DNA) was independently synthesized as the basic skeleton, and the bidirectional hybridization of h-DNA can increase the load of aptamer and signal probes, thereby realizing signal amplification. The high-efficiency fluorescence resonance energy transfer interaction between gold–palladium nanoparticles (Au–Pd NPs) and the self-synthesized fluorescent probe carbon dots (CDs) was utilized. Moreover, the label-free probe SYBR Green I (SG I) dye was introduced to form a double-signal probe with CDs, and a ratiometric sensor with FCDs/FSG I as a response signal was constructed. The ratio strategy can eliminate the fluctuation of external factors, thus improving the accuracy and reliability of the sensor. The quenching effect of Au–Pd NPs on CDs was 1.4 times that of AuNPs and 3.4 times that of Pd NPs, respectively. In the range 1–100 ng/mL, FCDs/FSG I showed a good linear relationship with the logarithm of the concentration of AFB1, and the limit of detection was as low as 0.07 ng/mL. The sensor was used to detect AFB1 in spiked peanuts and wine samples, and the recovery was between 91 and 115%, indicating that the sensor has high application potential in real sample analysis. [ABSTRACT FROM AUTHOR]

Aim: A multifunctional nanoplatform has been developed to enhance the targeting capability and biosafety of drug/siRNA for better diagnosis and treatment of myocardial infarction (MI). Materials & methods: The nanoplatform's chemical properties, biodistribution, cardiac magnetic resonance imaging (MRI) capabilities, therapeutic effects and biocompatibility were investigated. Results: The nanoplatform exhibited MI-targeting properties and pH-sensitivity, allowing for effective cardiac MRI and delivery of drugs to the infarcted myocardium. The GCD/Qt@ZIF-RGD demonstrated potential as a reliable MRI probe for MI diagnosis. Moreover, the GCD/si-SHP1/Qt@ZIF-RGD effectively suppressed SHP-1 expression, increased pro-angiogenesis gene expression and reduced cell apoptosis in HUVECs exposed to hypoxia/reoxygenation. Conclusion: Our newly developed multifunctional drug delivery system shows promise as a nanoplatform for both the diagnosis and treatment of MI. Graphical Abstract Article highlights The BSA-RGD-modified ZIF-8 nanoplatform is constructed. The nanoplatform encapsulates quercetin and SHP-1 siRNA as the therapeutic agents, and GCD as the MRI contrast agent. The nanoplatform is infarct-targeting and pH-sensitive, resulting in efficient drug/siRNA delivery. The GCD/si-SHP1/Qt@ZIF-RGD nanoparticles produce efficient gene silencing of SHP-1 in vitro and in vivo. The GCD/si-Con/Qt@ZIF-RGD promote angiogenesis and alleviate cell apoptosis on HUVECs under H/R. The GCD/si-SHP1/Qt@ZIF-RGD display better performance on promoting angiogenesis and alleviating cell apoptosis on HUVECs under H/R. The GCD/Qt@ZIF-RGD can serve as a promising MRI probe for MI imaging. The GCD/si-SHP1/Qt@ZIF-RGD nanoparticles show good biocompatibility. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) with an average diameter of 6.3 nm were synthesized from the medicinal seed extract of Syzygium cumini L. using one-pot hydrothermal synthesis. The prepared CDs exhibited excitation-dependent emission characteristics with photoluminescence (PL) emission maxima at an excitation of 340 nm. The CDs at 500 µg/mL displayed antimicrobial activities against four common pathogens. Both Staphylococcus aureus and S. epidermidis were completely eradicated by CDs within 12 h, compared to 24 h for Escherichia coli and Klebsiella pneumonia. The release of various oxygen species (ROS) was postulated to play a critical role in bacterial eradication. The CDs decorated on cotton fabric by ultrasonication also displayed good antibacterial activities against the above bacteria. The finding opens a plausible use of CDs in biomedical textiles with potent antimicrobial properties against both Gram-negative and Gram-positive bacteria. [ABSTRACT FROM AUTHOR]

This study presents a rapid and eco-friendly method for synthesizing carbon dots (CDs) using Cleome viscosa (CV) seeds powder via microwave carbonization. The synthesized CDs exhibit bright blue fluorescence under UV light, with a relative fluorescence quantum yield of 9.3%. Transmission electron microscopy (TEM) analysis revealed that the CDs possess an average diameter of 4.9 ± 1.2 nm and a spherical morphology and X-ray diffraction (XRD) patterns indicating their amorphous nature. Moreover, the CDs demonstrate robust fluorescence emission stability under diverse conditions including exposure to salt, continuous UV irradiation, pH variations, and prolonged storage. Furthermore, catalytic studies employing NaBH4-assisted reduction showcased the remarkable catalytic activity of the CDs towards the degradation of methylene blue (MB) and rhodamine B (RhB) dyes. The kinetics of the catalytic process followed pseudo first-order kinetics, yielding rate constants of 0.118 ± 0.002 min−1 and 0.161 ± 0.007 min−1 for MB and RhB, respectively. These findings underscore the potential of CV seed-derived CDs as efficient and versatile catalysts for wastewater treatment applications. [ABSTRACT FROM AUTHOR]

Since the beginning of nanoscience and nanotechnology, carbon dots (CDs) have been the foundational idea and have dominated the growth of the nano‐field. CDs are an intriguing platform for utilization in biology, technology, catalysis, and other fields thanks to their numerous distinctive structural, physicochemical, and photochemical characteristics. Since several carbon dots have already been created, they have been assessed based on their synthesis process, and luminescence characteristics. Due to their biocompatibility, less toxic effects, and most significantly their fluorescent features in contrast to other carbon nanostructures, CDs have several benefits. This review focuses on the most recent advancements in the characterization, applications, and synthesis techniques used for CDs made from natural sources. It will also direct scientists in the creation of a synthesis technique for adjustable carbon dots that is more practical, effective, and environmentally benign. With low toxicity and low cost, CDs are meeting the new era's requirements for more selectivity and sensitivity in the detection and sensing of various things, such as biomaterial sensing, enzymes, chemical contamination, and temperature sensing. Its variety of properties, such as optical properties, chemiluminescence, and morphological analysis, make it a good option to use in bioimaging, drug delivery, biosensors, and cancer diagnosis. [ABSTRACT FROM AUTHOR]

Heteroatom doping has become an important method to enhance the performance of traditional carbon dots in modern times. Selenium (Se) is a nonmetallic trace element with excellent redox properties and is therefore essential for health. Previous studies have mainly used pure chemicals as selenium sources to prepare selenium‐doped carbon dots (Se‐CDs), but the precursor pure chemicals have the disadvantages of being expensive, difficult to obtain, toxic, and having low fluorescence yields of the synthesised Se‐CDs. Fortunately, our team achieved successful synthesis of selenium carbon dots, exhibiting excellent luminescence and biocompatibility through a one‐step hydrothermal method using selenium‐enriched natural plant Cardamine, as an alternative to selenium chemicals. This approach aims to address the limitations and high costs associated with Se‐CDs precursors. Electron spin resonance spectroscopy (ESR) and cellular antioxidant tests have confirmed the protective ability of Se‐CDs against oxidative damage induced by excessive reactive oxygen species (ROS). A new concept and method for synthesizing selenium carbon dots on the basis of biomass, a rationale for the antioxidant effects on human health, and a wide range of development and application possibilities were offered in this work. [ABSTRACT FROM AUTHOR]

Herein, luminous blue carbon quantum dots (CDs) employing Anisomeles indica (Catmint) were reported with imaging, self‐targeting, and therapeutic effects on triple‐negative breast cancer (TNBC, MDA‐MB‐231) cells. The salient features of CDs generated from catmint are as follows: i) optical studies confirm CDs with excitation‐dependent emission; ii) high‐throughput characterization authenticates the formation of CDs with near‐spherical shape with diameter ranging between 5 and 15 nm; iii) CDs induce cytotoxicity (3.22 ± 0.64 μg/ml) in triple‐negative breast cancer (TNBC, MDA‐MB‐231) cells; iv) fluorescence microscopy demonstrates that CDs promote apoptosis by increasing reactive oxygen species (ROS) and decreasing mitochondrial membrane potential; v) CDs significantly up‐regulate pro‐apoptotic gene expression levels such as caspases‐8/9/3. Finally, our work demonstrates that catmint‐derived CDs are prospective nanotheranostics that augment cancer targeting and imaging. [ABSTRACT FROM AUTHOR]

A simple sensor for the quantitation of tryptophan (Trp) has been developed using a glassy carbon electrode (GCE) modified with electro-synthesized carbon dots functionalized with glycine (Gly@CDs). The surface functionalization with an amino acid led to the formation of large clusters of nanostructures. To our knowledge, this is the first study in which a Gly@CDs clusters modified GCE is used for the analysis of Trp. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) are the techniques used to study Trp electrochemical behavior in an alkaline solution using such an electrode. A linear concentration range was found for Trp from 5 × 10−6 to 5 × 10−3 mol L−1 with a detection limit (LOD) of 5 × 10−6 mol L−1. The reproducibility and repeatability data were satisfactory in terms of RSD%. Moreover, the stability during the time of the modified electrode was considered, evidencing interesting results. The described sensor was used for the determination of Trp in herbal tea and a dietary supplement, and the results were compared with those obtained with HPLC-ESI-MS in the Selected Ion Recording (SIR) mode as an independent method. The electrochemical sensor presents significant advantages in terms of low cost, portability, ease of handling and not requiring skilled personnel. [ABSTRACT FROM AUTHOR]

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