Nitrogen-doped Carbon Quantum Dots Research Articles

Green synthesis of multifunctional nitrogen-doped carbon quantum dots (N-CQDs) derived from citrus lemon juice: applications on antioxidant and antimicrobial activities and highly selective detection for Fe3+ ion sensing

Green synthesis of multifunctional nitrogen-doped carbon quantum dots (N-CQDs) derived from citrus lemon juice: applications on antioxidant and antimicrobial activities and highly selective detection for Fe3+ ion sensing

Antifungal Performance and Mechanisms of Carbon Quantum Dots in Cellulosic Materials.

Cellulosic materials, which are widely utilized in daily life, are highly susceptible to fungal degradation. However, commercial fungicides are usually toxic, posing severe threats to human health and the environment, highlighting the necessity of developing eco-friendly antifungal agents for cellulosic materials. In this work, we synthesized nitrogen-doped carbon quantum dots (CQDs) via a microwave-assisted method. CQDs with proper structure demonstrated significant antifungal effects against both brown-rot (Postia placenta, Pp) and white-decay fungi (Trametes versicolor, Tv) on various cellulosic materials. The underlying antifungal mechanisms of CQDs on cellulosic materials were further elucidated. We found that positively charged nanosized CQDs primarily adhered to and penetrated into fungal cell membranes. This led to fungal metabolism disorder, a significant reduction in enzymatic activities, and ultimately cell death, as confirmed by transcriptome analysis. Additionally, CQDs generated reactive oxygen species (ROS) under light, causing oxidation and dysfunction of the fungal cell wall. Furthermore, CQDs have the ability to chelate Fe3+, which results in the inhibition of the Fenton reaction and the hindering of the nonenzymatic cellulose degradation. These findings suggest that CQDs inhibit fungal degradation of cellulosic materials through integrated mechanisms, with potential implications for sustainable cellulose applications.

Nitrogen-doped carbon quantum dots from pumpkin for the sensing of nifuratel and temperature.

Nitrogen-doped carbon quantum dots from pumpkin for the sensing of nifuratel and temperature.

Nitrogen‐Doped Carbon Quantum Dot as Novel Nano Additive to Improve Performance and Fouling Resistance of Forward Osmosis Thin Film Nanocomposite Membranes

ABSTRACTForward osmosis (FO) is considered a strong and energy‐efficient desalination method. The thin film composite (TFC) membranes are widely used in the FO process. In this study, nitrogen‐doped carbon quantum dot (NCQD) was synthesized from citric acid (CA) and m‐phenylene diamine (MPD) as carbon and amine precursors, respectively, by a one‐step hydrothermal method. It was characterized completely by FT‐IR, XRD, UV–visible spectroscopy, DLS, and TEM analysis. Then, NCQD was incorporated in the polyamide (PA) layer to synthesize novel thin film nanocomposite (TFN) membranes. All membranes were analyzed by FT‐IR, WCA, AFM, and FE‐SEM. The TFN‐NCQD membrane, optimized with a concentration of 2000 ppm NCQD, exhibited outstanding FO performance, achieving a 70% increase in water flux compared to the pristine TFC. This membrane attained a peak water flux of 20.4 LMH, a reverse salt flux of 2.1 gMH, and showcased the best selectivity, with values as low as 0.10 g/L among the others. The strong interaction between amine functional groups of NCQD with both MPD and TMC during interfacial polymerization resulted in excellent adhesion and compatibility between the nanofiller and PA, increasing the lifespan of TFN membranes. Moreover, the novel TFN‐NCQD2 membrane showed better fouling behavior than pristine TFC, a 22% improvement when sodium alginate solution (600 ppm) was used as a foulant model.

Rapid Microwave-Assisted Synthesis of Nitrogen-Doped Carbon Quantum Dots as Fluorescent Nanoprobe for Sensitive Estimation of Tizanidine in Human Urine and Dosage Forms: Application to Content Uniformity Testing.

This study introduces a novel sensitive and environment-friendly spectrofluorimetric method for determination of an important muscle relaxant drug, tizanidine, with no need for using organic solvents or any pre-derivatization steps. This strategy depends on tizanidine quenching effect on the native fluorescence of newly synthesized nitrogen-doped carbon quantum dots (N-CQDs) from Tetraclinis articulata extract, for the first time, using a microwave-assisted synthetic strategy in only 4 min. Full characterization of the synthesized N-CQDs was performed by different microscopic and spectroscopic techniques. The synthesized N-CQDs showed good fluorescence emission at 380 nm when excited at 312 nm. This method is the first one for tizanidine analysis spectrofluorimetrically using N-CQDs as nanosensors. The developed approach demonstrated good linearity within the range of 0.1-1.0 μg/mL with a correlation coefficient of 0.9997 and a detection limit of 0.024 μg/mL. The developed approach was successfully applied for tizanidine estimation in its tablets and human urine samples with high % recoveries (98.04-101.67) and low %RSD (< 1.5) values. Furthermore, the content uniformity testing of the tizanidine tablets was performed in accordance with the USP guidelines. The method's eco-friendliness was evaluated using AGREE and ComplexGAPI metrics. Validation of the method was performed according to ICHQ2 (R2) guidelines.

An efficient ECL aptasensor based on resonance energy transfer between NCDs@Ag3PO4 and Cu-doped Cu: Eu MOF for the detection of diethylstilbestrol.

An efficient ECL aptasensor based on resonance energy transfer between NCDs@Ag3PO4 and Cu-doped Cu: Eu MOF for the detection of diethylstilbestrol.

Enhanced charge separation and visible-light harvesting in Bi2MoO6 via nitrogen-doped carbon quantum dots for improved antibiotic degradation

Enhanced charge separation and visible-light harvesting in Bi2MoO6 via nitrogen-doped carbon quantum dots for improved antibiotic degradation

Fluorescent responsive film based on nitrogen-doped carbon quantum dots embedded in mesoporous silica for visual detection of Cr(VI)

Fluorescent responsive film based on nitrogen-doped carbon quantum dots embedded in mesoporous silica for visual detection of Cr(VI)

Anthraquinone-rich Rheum ribes L. as a source of nitrogen-doped carbon quantum dots for ZnO-based S-scheme heterojunction photocatalysts in tetracycline degradation

Anthraquinone-rich Rheum ribes L. as a source of nitrogen-doped carbon quantum dots for ZnO-based S-scheme heterojunction photocatalysts in tetracycline degradation

Highly Selective and Instant Ratio Fluorescence-Scattering Sensor for Phosphate Detection in a Water Environment by a Stable Eu3+/Y3+-Modified Nitrogen-Doped Carbon Quantum Dot.

Developing an accurate sensor for the detection of phosphate ions (Pi, a crucial indicator of water quality) in water environments is of great significance. Fluorescence-scattering ratiometric probes with great promise to achieve sensitive and selective detection are still hindered by the poor solubility and stability and complex construction of fluorescence composites. In this paper, a simple ratio fluorescence-scattering sensor based on Eu3+- and Y3+-modified nitrogen-doped carbon quantum dots (NCQDs) was developed for Pi rapid detection. It is found that Eu3+ can specifically recognize Pi and form ternary ion chelates with Pi and NCQDs, resulting in decreased fluorescence signals of NCQDs at 420 nm and increased second-order scattering (SOS) signals at 640 nm. Y3+ as the sensitizer of Eu3+ promotes the aggregation of NCQDs, thereby enhancing the sensitivity of the sensor. The ratio fluorescence-scattering probe based on NCQDs-Eu3+-Y3+ shows a high sensitivity, a low detection limit of 0.08 μM, a rapid response time of within 2 s, and a wide detection range from 1 to 150 μM. Moreover, the proposed probe showed excellent selectivity and stability, and the relative standard deviation (RSD) of seven cycles of Pi detection is only 0.559%. Furthermore, the accurate detection of Pi (RSD < 5%) in real environmental water samples confirmed the practicality of the proposed sensor. This ratio fluorescence-scattering sensor provides a novel method for the detection of Pi with a simple preparation process and excellent detection performance, having great application potential for the fast on-site detection of Pi.

Preparation of carbon quantum dots biofilm and adsorption of heavy metal Cu2+

Currently, seawater is seriously polluted by Cu2+, thus the development of safe and efficient Cu2+ removal materials is important for maintaining the safety of marine ecology. In this study, we utilized reed and urea as raw materials, synthesizing carbon quantum dots (CQDs) and nitrogen-doped carbon quantum dots (N-CQDs) through the hydrothermal method. Then, we analyzed their performance in Cu2+ detection and absorbance. Both the CQDs and N-CQDs exhibited excellent fluorescent properties, with maximum excitation wavelengths at 325 nm and corresponding emission wavelengths at 400 nm. Nitrogen doping enhanced the fluorescence intensity and stability of CQDs. Various metal ions were tested for their fluorescence-quenching effects on CQDs and N-CQDs. The results indicated that the N-CQDs exhibited strong adsorption capacity towards Cu2+, showing a good linear relationship at Cu2+ concentrations ranging from 0 to 50 μmol/L with a detection limit of 1.081 μmol/L. Additionally, we prepared a CQDs-biofilm using 3% chitosan as raw material and evaluated the adsorption of Cu2+ by the N-CQDs biofilm. The findings revealed that the Cu2+ adsorption rate of the N-CQD biofilm ranged from 28% to 67%. This CQD-biofilm is significant for trace detection and pollution control of Cu2+ in aqueous media.

Preparation of Nitrogen-Doped Carbon Quantum Dots and their Application in Detecting Heavy Metal Ions in Polymetallic Deposits

Preparation of Nitrogen-Doped Carbon Quantum Dots and their Application in Detecting Heavy Metal Ions in Polymetallic Deposits

Ultrasensitive and rapid detection of Hg2+ in milk based on β-galactosidase driven colloidal motors.

Ultrasensitive and rapid detection of Hg2+ in milk based on β-galactosidase driven colloidal motors.

Preparation of a biodegradable packaging film by konjac glucomannan/sodium alginate reinforced with nitrogen-doped carbon quantum dots from crayfish shell for crayfish meat preservation.

Preparation of a biodegradable packaging film by konjac glucomannan/sodium alginate reinforced with nitrogen-doped carbon quantum dots from crayfish shell for crayfish meat preservation.

Nitrogen doped carbon quantum dots (N-CQDs) synthesized by a microwave assisted hydrothermal method in combination with gold nanoparticles (AuNPs) as sensitive dual sensor for antibiotic meropenem detection

Nitrogen doped carbon quantum dots (N-CQDs) synthesized by a microwave assisted hydrothermal method in combination with gold nanoparticles (AuNPs) as sensitive dual sensor for antibiotic meropenem detection

Fluid-induced piezoelectric field enhanced photocatalytic antibiotic removal over nitrogen-doped carbon quantum dots/Bi2WO6@polyvinylidene fluoride-co-hexafluoropropylene membrane in aqueous environments.

Fluid-induced piezoelectric field enhanced photocatalytic antibiotic removal over nitrogen-doped carbon quantum dots/Bi2WO6@polyvinylidene fluoride-co-hexafluoropropylene membrane in aqueous environments.

Reactive deep eutectic solvents: Refining lignocellulosic biomass of wheat straw into nano building blocks for a more sustainable sensor fabrication.

Reactive deep eutectic solvents: Refining lignocellulosic biomass of wheat straw into nano building blocks for a more sustainable sensor fabrication.

Inactivation of antibiotic resistant bacteria by nitrogen-doped carbon quantum dots through spontaneous generation of intracellular and extracellular reactive oxygen species.

Inactivation of antibiotic resistant bacteria by nitrogen-doped carbon quantum dots through spontaneous generation of intracellular and extracellular reactive oxygen species.

Engineering nitrogen-doped carbon quantum dots: Nitrogen content-controlled dual-phase emission behavior.

Engineering nitrogen-doped carbon quantum dots: Nitrogen content-controlled dual-phase emission behavior.

Dual-functional ratiometric fluorescence sensor based on silica spheres for highly selective detection of Hg2+ and Fe3+

Dual-functional ratiometric fluorescence sensor based on silica spheres for highly selective detection of Hg2+ and Fe3+