Carbon Dots Research Articles

Self-adaptive carbon nanozyme regulation of ROS balance for bacteria-infected wound therapy

Nanozymes sterilizing drug-resistant (DR) bacteria by generating reactive oxygen species (ROS) have emerged as a promising approach for treating infected wounds. However, designing biocompatible adaptive ROS balance therapeutic platform for DR bacteria-infected wounds remains a great challenge. Herein, biocompatible lignin-based carbon dot nanomaterials (LCDs-OA) with more CO and COOH functional groups on the surface were prepared by hydrothermal organic acid co-processing and used as a dual enzyme-like active nanozyme for the therapy of wounds infected by DR bacteria. Experimental and theoretical calculations demonstrated that the CO and COOH functional groups in LCDs-OA have site-switching roles in the dual enzyme-like activity, which can balance reactive oxygen species (ROS) according to the changes in microenvironmental pH at the wound site, and realize the adaptive regulation of ROS generation for bactericidal and ROS scavenging for healing. Furthermore, the performance differences between different organic acid treatments were investigated and an adaptive ROS balance therapeutic platform (LCDs-OA@CaO2) was constructed to overcome the major limitation in treating DR bacterial infected wounds. The system achieved >99.6 % in vitro antimicrobial efficiency against DR bacteria and was highly biocompatible while effectively reducing oxidative damage to normal tissues, resulting in satisfactory therapeutic results in repairing wounds infected with DR bacteria.

A novel ratiometric fluorescent nanosensor based-on UiO-66-NH2 capped carbon dots for nitrite determination

Nitrite is a commonly used food preservative and a water contaminant that has garnered significant attention due to its harmful effects on human health. Developing a simple and sensitive method for determining nitrite levels is crucial for safeguarding public health. In this paper, we present a novel ratiometric fluorescent nanosensor (CDs@UiO-66-NH2), created by combining orange-red-emitting CDs with blue-emitting UiO-66-NH2. This ratiometric probe detects nitrite ions (NO2−) based on the diazotization reaction between the amino group in UiO-66-NH2 and the target NO2−, where the blue emission of UiO-66-NH2 is quenched but the orange-red emission of CDs remains stable. The probe demonstrated a detection range of 0.5–20 μM with a limit of detection (LOD) of 0.157 μM for NO2−. Due to the probe’s distinct color changes in response to NO2−, RGB values can be easily read using a smartphone, enabling ultrasensitive visual detection of NO2− with an LOD of 0.76 μM. This sensor was successfully applied to detect NO2− in environmental water samples. Finally, a smartphone-based RGB reading method using CDs@UiO-66-NH2 for visual quantitative detection of NO2− was proposed, broadening the application of CDs@UiO-66-NH2 in environmental protection.

Multifunctional fish gelatin film incorporated with chitosan carbon dots and butterfly pea flower anthocyanins for active/smart packaging of Pacific white shrimp

Multifunctional fish gelatin film incorporated with chitosan carbon dots and butterfly pea flower anthocyanins for active/smart packaging of Pacific white shrimp

Opal‐Inspired SiO2‐Mediated Carbon Dot Doping Enables the Synthesis of Monodisperse Multifunctional Afterglow Nanocomposites for Advanced Information Encryption

AbstractDespite recent advancements in inorganic and organic phosphors, creating monodisperse afterglow nanocomposites (NCs) remains challenging due to the complexities of wet chemistry synthesis. Inspired by nanoinclusions in opal, we introduce a novel SiO2‐mediated carbon dot (CD) doping method for fabricating monodisperse, multifunctional afterglow NCs. This method involves growing a SiO2 shell matrix on monodisperse nanoparticles (NPs) and doping CDs into the SiO2 shell under hydrothermal conditions. Our approach preserves the monodispersity of the parent NP@SiO2 NCs while activating a green afterglow in the doped CDs with an impressive lifetime of 1.26 s. Additionally, this method is highly versatile, allowing for various core and dopant combinations to finely tune the afterglow through core‐to‐CD or CD‐to‐dye energy transfer. Our findings significantly enhance the potential of SiO2 coatings, transforming them from merely enhancing the biocompatibility of NCs to serving as a versatile matrix for emitters, facilitating afterglow generation and paving the way for new applications.

Calcination-Controlled Synthesis of Carbon Dots@MgF2 Composites with Yellow, White, and Ultraviolet-Blue Thermally Activated Delayed Fluorescence for Multilevel Information Encryption.

It is attractive but challenging to develop carbon dot (CD) based materials with tunable thermally activated delayed fluorescence (TADF), especially in the long wavelength region. Here, by simply calcinating the mixture of m-phenylenediamine and MgF2 at 300-500 °C, a series of CDs@MgF2 composites exhibiting yellow, white, and ultraviolet-blue TADF with high photoluminescence quantum yields of up to 37.6% are prepared. Photophysical studies reveal that the yellow TADF with long lifetimes of 810-1106ms originates from the surface emission centers of CDs, while the ultraviolet-blue TADF with short lifetimes of 266-379ms is related to the carbon core emission centers. The combination of yellow and ultraviolet-blue TADF in a single material triggers dynamic afterglow with time-dependent colors from white to yellow. The MgF2 matrix offers multiple confinement of CDs through a rigid network, strong space constraint, and robust covalent/hydrogen bonding, thus preventing the triplet excitations from non-radiative transitions. The electron-withdrawing fluorine atoms induce substantial spin-orbit coupling and reduce the singlet-triplet energy gap, consequently facilitating the reverse intersystem crossing to enhance TADF efficiency. Importantly, the CDs@MgF2 composites possess outstanding optical stability against water, organic solvents, strong acids, bases, and oxidants. The fascinating TADF features enable the successful demonstration of multilevel information encryption using CDs@MgF2.

Early Diagnosis of Triple-Negative Breast Cancer Based on Dual microRNA Detection Using a Well-Defined DNA Crown-Carbon Dots Structure as an Electrochemiluminescence Sensing Platform.

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer (BC). Thus, early detection and accurate diagnosis of this cancer are crucial for improving the survival rate of patients. Specific microRNAs (miRNAs) have been implicated in the occurrence, proliferation, and metastasis of TNBC. Addressing this need, our study developed a biosensor platform for early and accurate TNBC diagnosis by integrating electrochemiluminescence (ECL) technology with a DNA sensing strategy. Specifically, synthesized positively charged carbon dots (CDs) were used to neutralize the electrostatic repulsion between DNA strands and facilitate the assembly of DNA triangular prisms (DNA TP-CDs). Hairpins were then incorporated into the DNA TP-CDs to form the final DNA crown structure. The early TNBC biomarker, microRNA-93-3p (miR-93-3p), allowed for the binding between the DNA Crown and the DNA track on the electrode and initiated the ECL signal. Subsequently, microRNA-210 (miR-210) unlocked the DNA tripedal walker, and its movement on the DNA Crown eventually quenched the ECL signal, enabling accurate TNBC diagnosis and tumor stage assessment. Our proposed biosensor had satisfactory sensing efficiency due to the ordered DNA track and rapid-moving DNA walker. The data revealed a good linear relationship between the ECL signals and the logarithm of miRNA concentrations, with miR-93-3p having a detection limit of 31.04 aM and miR-210 having a detection limit of 7.69 aM. The biosensor also showed satisfactory performance in serum samples and cells. Taken together, this study hopes to provide ideas and applications for clinical diagnosis as well as the personalized treatment of TNBC.

Synthesis of nanohybrid consisting of taurine derived carbon dots and nanoceria for anticancer applications

Here, we first synthesized carbon dots (CDs) from taurine and then a nanohybrid with ceria (CeO2) nanoparticles using thermal decomposition method for checking their antineoplastic efficacy against human triple negative mammary carcinoma cells, MDA-MB-231. The in vitro study demonstrated significant dose-dependent antineoplastic activity of the nanohybrids within a range of concentration from 10 to 50 μg/mL after 48 h of treatment. The cellular morphology analysis clearly depicted substantial amount of cell death which seems to stem from increased intracellular reactive oxygen species (ROS) production. However, the maximum anticancer activity of the nanohybrid as compared to bare CDs and CeO2 is supposed to be due to the combined anticancer effect of both CDs and CeO2 (a well-established antitumor agent). Further we have performed molecular docking study to reveal the anticancer mechanism of CDs which exhibited high binding capacity towards several proapoptotic and antiapoptotic protein molecules. The binding affinity values were found to be – 8.7 kcal/mol, – 7.9 kcal/mol, – 9.6 kcal/mol, – 9.5 kcal/mol, – 12 kcal/mol and – 11.1 kcal/mol for BAD, BCl-2, p53, Caspase-8, Caspase-9 and Caspase-3 respectively. Taken together, our synthesized CDs-CeO2 nanohybrid could be thought as a potential anticarcinogenic option in the field of breast cancer therapeutics.

Fluorescent Carbon Dots with Red Emission: A Selective Sensor for Fe(III) Ion Detection

We present a procedure for the synthesis and purification of p-phenylenediamine-based carbon dots that can be used for the recognition of Fe(III) ions. Carbon dots have an approximately spherical shape with an average size of 10 nm and are composed of a carbonaceous core surrounded by functional groups attached to it, both of which are responsible for their dual fluorescence properties. The emission bands have a different behavior, with a blue band dependent and a red emission independent of the excitation wavelength, respectively. Red emission is appropriate for the detection of ions and other molecules in biological environments because this high wavelength prevents the occurrence of processes such as resonance energy transfer and internal filter effects. In particular, the presence of Fe(III) ions produces an important quenching phenomenon that can be applied to the fabrication of a sensor. The platform is very sensitive, with a detection limit of 0.85 µM, which is within the lowest values reported for this ion, and a high selectivity that is believed to be due to the formation of a specific complex in the ground state through specific interactions of Fe (III) ions with pyridinic and amino groups on the surface of the nanomaterials.

A cotton swab platform for fluorescent detection of aluminum ion in food samples based on aggregation-induced emission of carbon dots.

A novel portable cotton swab based on nitrogen-doped carbon dots (NCDs) for Al3+ detection was constructed for the first time. NCDs with bright green fluorescence were prepared by hydrothermal method with phenylhydrazine hydrochloride and 3-hydroxy-2-naphthoic acid hydrazide as precursors. The surface of NCDs was exposed to abundant functional groups (such as amino, carboxyl, hydroxyl, etc.), which was helpful for the formation of complexes between NCDs and Al3+. In the presence of Al3+, the aggregation of NCDs obviously induced their fluorescence enhancement due to the aggregation-induced emission (AIE) of NCDs. Furthermore, the quantum yield (QY) of NCDs was enhanced by 12 times with Al3+, and the fluorescence lifetime was increased by 7.54ns. The fluorescence intensity was linearly correlated with the concentration of Al3+ (2.5-300μM), and the limit of detection was 0.76μM. Moreover, for the portable way, cotton swabs were successfully employed to construct the sensors for the detection of Al3+ in food samples. This proposal haspotential for the application in food analysis.

Carbon quantum dots in breast cancer modulate cellular migration via cytoskeletal and nuclear structure

Carbon nanomaterials have been widely applied for cutting edge therapeutic applications as they offer tunable physio-chemical properties with economic scale-up options. Nuclear delivery of cancer drugs has been of prime focus since it controls important cellular signaling functions leading to greater anti-cancer drug efficacies. Better cellular drug uptake per unit drug injection drastically reduces severe side-effects of cancer therapies. Similarly, carbon dots (CDs) uptaken by the nucleus can also be used to set-up cutting edge nano delivery systems. In an earlier paper, we showed the cellular uptake and plasma membrane impact of combustion generated yellow luminescing CDs produced by our group from fuel rich combustion reactors in a one-step tunable production. In this paper, we aim to specifically study the nucleus by establishing the uptake kinetics of these combustion-generated yellow luminescing CDs. At sub-lethal doses, after crossing the plasma membrane, they impact the actin and microtubule mesh, affecting cell adhesion and migration; enter nucleus by diffusion processes; modify the overall appearance of the nucleus in terms of morphology; and alter chromatin condensation. We thus establish how this one-step produced, cost and bulk production friendly carbon dots from fuel rich combustion flames can be innovatively repurposed as potential nano delivery agents in cancer cells.

Novel fluorescent carbon dots derived from shikimic acid for ultra-high sensitive detection and efficient removal of sulfasalazine

The extensive use of sulfasalazine (SSZ) poses potential threats to human health and ecosystems. Therefore, sensitive detection and simultaneous efficient removal of sulfasalazine is greatly desirable. Meanwhile, shikimic acid, a natural product obtained from Chinese star anise is a promising precursor for carbon dots construction due to its unique structure. Taking the above into account, in this work, novel fluorescent carbon dots (SA-CDs) for sensitive detection and highly efficient removal of sulfasalazine have been developed. SA-CDs were facilely obtained from shikimic acid by using one-pot hydrothermal synthesis. The structure and composition of SA-CDs were fully characterized with TEM, PXRD, FT-IR, DLS and XPS tests. Strong fluorescent emission centered at 428 nm was recorded for SA-CDs, enabling the detection of SSZ. Quantitatively speaking, SA-CDs can selectively detection SSZ amount 17 antibiotics with an experimental limit of detection (LOD) of 100 nM and a calculated LOD of 60 pM. Adsorption experiments suggested that chemical monolayer adsorption predominates in the adsorption process, with a maximum adsorption capacity of 22.67 mg/g. Aggregations formed during detection enable the simultaneous removal of SSZ upon centrifugation. Moreover, SA-CDs have been successfully applied to the detection of SSZ in real samples, including river water, soil, tea and eggs.

Elucidating carbon dot research coupled with bibliometric analysis

Over the past two decades, carbon dots (CDs) have been a subject of extensive research. Despite this progress, a holistic view of the research trajectory and future directions remains elusive. In an effort of shedding light on the evolution of CD research, herein an objective and comprehensive analysis was conducted using bibliometric techniques. By examining the relationships among different research components such as publications, citations, authors, institutions, and keywords, research questions related to identifying trends, key themes, prominent journals, influential authors and the overall intellectual structure of CD research has been addressed. This involved examining 24,599 publications from the Web of Science Core Collection spanning from 2004 to 2024. These publications represent the collective work of approximately 66,000 authors from around 8,000 institutions across 115 countries. China accounted for nearly 50 % of these publications, with the Chinese Academy of Sciences standing out as the most prolific institution. Authors with nine or more publications emerged as the core authors. Publications were categorized in accordance with the United Nations Sustainable Development Goals. The primary areas of CD research have been identified as synthesis (emphasizing green, simple, and hydrothermal methods), sensing capabilities, photoluminescence properties, photocatalytic activity, composite materials, drug delivery systems, and bioimaging techniques. Lastly, the factual state of CD research has been subjectively stated quite briefly.

Molecular Targets and Nano-Technological Approaches in the Treatment of Hepatic Carcinoma.

Liver cancer is a leading cause of cancer-related mortality, with about one million people losing their lives each year. The disease becomes even more dangerous when tumors cannot be removed through surgery. Globally, hepatocellular carcinoma (HCC) ranks third in terms of fatality rates among liver cancers. It is also the most frequent type of liver cancer. Due to the high mortality rate associated with this malignancy, it is a hotspot for researchers looking to improve treatment methods. Nanotechnology plays an important part in these at-tempts. Various types of nanoparticles (NPs) have been investigated for their ability to fight liver cancer. NPs are a vast class of materials. The article details the efforts made to include inorganic NPs, such as silver, gold, metal oxide, platinum, calcium, selenium, and other un-common materials into drug delivery systems (DDS) for therapeutic, carrier, or imaging pur-poses. This review discusses the function of carbon-based NPs in DDS for the treatment of liver cancer, including polymeric, polysaccharide, lipid, and carbon dot NPs, all of which have been extensively researched for this purpose. The purpose of this review is to provide a con-cise overview of recent developments in the field of HCC based on current research and clini-cal diagnosis and treatment guidelines. Further goals include elucidating the current state of nanomaterials research, its limitations, and the potential for future advancements in the field, as well as the use of nanotechnology in the detection and treatment of HCC.

Carbon dots induced homeotropic alignment in a negative dielectric nematic liquid crystal material

Abstract Recently, doping guest materials such as quantum dots (QDs) into liquid crystals (LCs) has been of great interest since their addition substantially enhances the properties of LC and opens new avenues for scientific advancement. Here, we report the induction of homeotropic alignment in cells without alignment layers of the negative dielectric nematic liquid crystal, N-(4-Methoxybenzylidene)-4-butylaniline (MBBA) by doping with carbon dots (CDs ~2.8±0.72 nm). The CDs-MBBA composites (CDs concentration: 0.002, 0.01, 0.03, 0.1 and 0.3 wt%) were investigated using optical polarising microscopy, electro-optical and dielectric techniques. Polarizing optical micrographs and voltage dependent optical transmission revealed the induced homeotropic alignment for all the composites under investigation. Interestingly, the least concentrated sample, 0.002 wt% exhibited partial homeotropic alignment. However, due to light leakage, the optical transmission value below threshold voltage was relatively higher than the rest of the composites. MBBA is a negative dielectric material, hence the application of a voltage across the cell was able to switch the alignment from a dark to a bright state for all composites. However, above a certain voltage (> threshold voltage), the bright state produced some instabilities. The value of dielectric permittivity was observed to decrease with increasing concentration, confirming the effect of CDs in producing homeotropic alignment in MBBA. Measurements as a function of temperature were conducted to examine the thermal stability of the induced alignment. The alignment was found to be stable throughout the nematic phase of MBBA. The induction of such alignment without conventional alignment (i.e., rubbing of polyimides) technique can be helpful in addressing the evolving display demands by making liquid crystal displays (LCDs) and other display devices cost effective.

Fluorescent and colorimetric dual-mode recognition of Al3+ in tablets based on chrome azurol S and pH-switchable boron, nitrogen co-doped carbon dots.

The synthesis and characterization ofpH-sensitive boron and nitrogen co-doped CDs (B, N-CDs) is reported. The fluorescence of B, N-CDs exhibited pH-responsive behavior within the range pH3.0-6.0, attributed to their controlled aggregation and disaggregation. Interestingly, the fluorescence of B, N-CDs was quenched by the inner filter effect from chrome azurol S (CAS). With the subsequent addition of Al3+, the fluorescence of B, N-CDs was restored due to the formation of blue Al3+-CAS and B, N-CDs-Al3+ complexes. Consequently, a fluorescent and colorimetric dual-mode sensor for Al3+ detection was developed. The proposed sensor enabled Al3+ detection in the ranges and limits of detection of 3.75-22.5μM and 2.67μM for the fluorescent mode and 5-20μM and 4.8μM for the colorimetric mode, respectively. Furthermore, the efficacy of the sensor was validated through successful detection of Al3+ in tablet samples. The obtained B, N-CDs promised the application in acid condition and the proposed sensor isexpected tobe applied toin situ on-line detection of Al3+.

Femtosecond Laser Synthesis of Carbon Dots from Amino Acids for Fluorescent Bioimaging and Sensing

Femtosecond Laser Synthesis of Carbon Dots from Amino Acids for Fluorescent Bioimaging and Sensing

Spectrofluorometric Turn-Off Sensing Probe for Tolmetin Determination Using Cerium and Nitrogen Codoped Carbon Dots.

A facile, low-cost, and rapid method was developed for spectrofluorometric determination of tolmetin (TOL) using highly fluorescent (QY = 35%) cerium and nitrogen codoped carbon dots (Ce-NCDs) sensing platform prepared by one-step hydrothermal method. Owing to the severe overlap between TOL absorption and Ce-NCDs excitation spectra around 320 nm, TOL could attenuate the emission of Ce-NCDs at 407 nm through primary inner filter effect (IFE). This concentration dependent attenuation was linear between 2 and 10 μg/mL (r = 0.9993) with a limit of detection of 0.5 μg/mL. The sensor showed very good accuracy (% recovery = 98%-100%) and precision (%RSD < 2). The developed sensing strategy was successfully applied for TOL detection as an active pharmaceutical ingredient in pharmaceutical formulation and as a potential pollutant in environmental water samples, such as tap and river water, with acceptable recovery and considerable selectivity. Thus, the direct single-step spectrofluorometric determination of TOL was enabled without extensive processing or chemical derivatization.

Carbon Dots Enabling High-Performances Sodium-Ion Batteries.

Carbon dots (CDs), known for their quantum size, abundant surface functional groups, excellent biocompatibility, and non-toxicity, have emerged as promising candidates for enhancing various advanced rechargeable batteries. Recent research indicates that electrodes based on or modified with CDs in sodium-ion batteries (SIBs) have shown significant improvements in key performance metrics such as Coulombic efficiency, cycle life, and capacity compared to traditional electrodes. Several key impacts of CDs contribute to these enhancements, including increased conductivity due to their conductive graphitized core, rich absorption sites, and excellent dispersity facilitated by abundant surface functional groups. These features accelerate ion transport through interface edges and ion diffusion paths, inhibit electrode material dissolution, buffer electrode material volume expansion, ensure electrode uniformity and stability, and promote the electrochemical reaction process between the electrode and electrolyte. This review summarizes recent developments, challenges, and opportunities in leveraging CDs as additives in SIBs, focusing on their impact on electrolyte properties, electrode materials, and overall battery performance. It provides a comprehensive understanding of the potential of CDs to significantly advance SIB technology.

A Novel Carbon Dot-Bromothymol Blue System for Ratiometric Colorimetric-Fluorometric Sensing of Glutathione in Urine: A Smartphone-Compatible Approach.

This study presents a novel dual-modal approach for glutathione (GSH) detection using blue and yellow dual-emission carbon dots (BY-CDs) and bromothymol blue (BTB) at pH 8.0. The method employs both colorimetric and fluorometric detection modes, offering a new perspective on GSH quantification. BTB's blue coloration induces selective fluorescence quenching of the CDs' 610nm emission peak, with minimal effect on the 445nm peak. Upon GSH addition, the quinonoid structure (blue color) of BTB transforms to its benzenoid form (yellow color). This transformation triggers fluorescence restoration at 610nm and significant quenching at 445nm, enabling ratiometric fluorescence analysis (F610/F445). Concurrently, colorimetric detection is also ratiometric, based on measuring the ratio between the emerging yellow color peak (435nm) and the decreasing blue color peak (618nm) (A435/A618). The state-of-the-art aspect of this detection method lies in the strategic choice of dual-emission CDs and a dye with distinct absorption spectra that closely match the emission spectra of the CDs. This unique combination allows for dual detection with opposite responses in the two detection modes, enhancing selectivity and reliability. The probe was thoroughly characterized, and its detection mechanism was elucidated using various spectroscopic techniques. The method shows excellent linearity, a broad detection range, and low detection limits for both fluorometry (0.02 - 10.0μM, 5.88nM) and colorimetry (1.0 - 35.0μM, 301.25nM). Additionally, a smartphone-based platform was developed for colorimetric GSH determination, enhancing the method's potential for on-site analysis. The assay's practicality was validated through successful application to human urine samples, yielding excellent recovery values (97.33% to 99.13%).

Preparation of D-NCCDs and its application in fluorescent/colorimetric dual-mode discrimination of glutamine enantiomers.

Anew type of carbon dots (D-NCCDs) was synthesized by 3, 5-diaminobenzoic acid, N,N-dimethyl-o-phenylenediamine, and D-cysteine. The morphology and structure of D-NCCDs were investigated by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and FT-IR spectra, and the chirality was characterized by circular dichroism. In the presence of hydrogen peroxide, the fluorescence of D-NCCDs at 487nm (λex = 410nm) showed great discrimination ability towards glutamine enantiomers. The ratio of fluorescence intensity (F/F0) to the concentration of D-Gln showed good linearity in the range 0.5-10mM, with a detection limits of 0.11mM. Meanwhile, the color of the solution gradually changed from light yellow to yellow-brown. The UV-Vis absorption ratio (A/A0) at 410nm showed good linearity with the concentration of D-Gln in the range 0.5 to 20mM; the detection limit is 7.7μM. But the fluorescence and absorbance of D-NCCDs showed no significant change after the addition of L-glutamine. Thus, fluorescence and colorimetry dual-mode discrimination of glutamine enantiomers was achieved. The fluorescence enantioselectivity of Gln (FL-Gln/FD-Gln) is 1.62, and the colorimetric enantioselectivity of Gln (AD-Gln/AL-Gln) is 2.14. The chiral discrimination mechanism of D-NCCDs to Gln enantiomers was also investigated systematically. This work not only can discriminate glutamine enantiomers with high sensitivity and convenience, but also offers a new strategy for preparing new dual mode chiral nanoprobes.