Fluorescent Carbon Quantum Dots Research Articles

Comprehensive Overview of Controlled Fabrication of Multifunctional Fluorescent Carbon Quantum Dots and Exploring Applications.

In recent years, carbon dots (CDs) have garnered increasing attention due to their simple preparation methods, versatile performances, and wide-ranging applications. CDs can manifest various optical, physical, and chemical properties including quantum yield (QY), emission wavelength (Em), solid-state fluorescence (SSF), room-temperature phosphorescence (RTP), material-specific responsivity, pH sensitivity, anti-oxidation and oxidation, and biocompatibility. These properties can be effectively regulated through precise control of the CD preparation process, rendering them suitable for diverse applications. However, the lack of consideration given to the precise control of each feature of CDs during the preparation process poses a challenge in obtaining the requisite features for various applications. This paper is to analyze existing research and present novel concepts and ideas for creating CDs with different distinct features and applications. The synthesis methods of CDs are discussed in the first section, followed by a comprehensive overview of the important properties of CDs and the modification strategy. Subsequently, the application of CDs and their requisite properties are reviewed. Finally, the paper outlines the current challenges in controlling CDs properties and their applications, discusses potential solutions, and offers suggestions for future research.

The Brown Sugar Mediated Carbon Quantum Dots as a Novel Fluorescence Sensor for Sensitive Detection of Gentamicin and Its Application in Foods.

In this work, a novel fluorescence sensing strategy was proposed for the detection of gentamicin based on fluorescent carbon quantum dots (CQDs) and gold nanoparticles (AuNPs). Herein, the CQDs were green-synthesized for the first time via a one-step hydrothermal method utilizing brown sugar as the precursor. In the presence of citrate-stabilized AuNPs, the fluorescence of CQDs was quenched efficiently. Gentamicin, on the other hand, had a higher affinity for AuNPs and was able to compete with CQDs for a preferential binding to AuNPs, which ultimately led to the aggregation of AuNPs and freeing of CQDs in solution, causing the fluorescence recovery of CQDs. Based on the above phenomenon, the concentrations of gentamicin could be ascertained by detecting the variations in fluorescence intensity of CQDs. This sensing strategy exhibited excellent selectivity in various antibiotics. At the same time, the method displayed outstanding sensitivity for gentamicin, which was successfully applied to real samples detection.

Synthesis of fluorescent carbon quantum dots from Manihot esculenta waste peels for nonlinear optical and biological applications

The synthesis of carbon quantum dots using cassava (Manihot esculenta) waste peels by simple hydrothermal method. Carbon quantum dots were studied using PXRD, and HRTEM analysis, signifying an amorphous graphite carbon structure. The carbon quantum dots have two absorption peaks in the UV–vis spectrum, around 272 and 304 nm which lead to the π–π* and n–π* transitions. The produced CQDs exhibit excitation dependent fluorescence characteristics, with a fluorescence quantum yield of 4.664% at an excitation wavelength of 330 nm. The CQDs revealed a white light emitting diode with the Commission Internationale d'Eclairage (CIE) coordinates (0.35, 0.35). The nonlinear optical absorption 0.294×10−4 (cm/W), nonlinear refractive index 1.8138×10−8 (cm2/W), and third-order NLO susceptibility 5.5 × 10−6 (esu) were calculated using Z-Scan analysis. The synthesized CQDs were utilized for their antibacterial activity used S. aureus (23 mm), B. cereus (33 mm), E. coli (43 mm), and P. aeruginosa (30 mm) as harmful microbes. Our results suggest that Manihot esculenta waste peels CQDs have potential for application in NLO devices, optical switching, and pharmaceuticals.

Development of a highly sensitive fluorescent probe using Delonix regia (Gulmohar) tree pod shell for precise sarcosine detection in human urine samples: advancing prostate cancer diagnosis

We designed a highly sensitive fluorescent sensor for the early detection of sarcosine, a potential biomarker for prostate cancer. This sensor was based on surface-cobalt-doped fluorescent carbon quantum dots (Co-CD) using a FRET-based photoluminescent sensing platform. Blue luminescent carbon quantum dots (CQD) were synthesised through a hydrothermal approach, utilizing Delonix regia tree pod shells. Cobalt was employed to functionalize the CQD, enhancing the quantum-entrapped effects and minimizing surface flaws. To optimize Co-CD preparation, we employed a Box-Behnken design (BBD), and response surface methodology (RSM) based on single-factor experiments. The Co-CD was then used as a fluorescent probe for selective Cu2+ detection, with Cu2+ quenching Co-CD fluorescence through an energy transfer process, referred to as ‘turn-off’. When sarcosine was introduced, the fluorescence intensity of Co-CD was restored, creating a ‘turn-on’ response. The sensor exhibited a Cu2+ detection limit (LOD) of 2.4 µM with a linear range of 0 μM to 10 µM. The sarcosine detection in phosphate buffer saline (PBS, pH 7.4) resulted in an LOD of 1.54 μM and a linear range of 0 to 10 µM. Importantly, the sensor demonstrated its suitability for clinical analysis by detecting sarcosine in human urine. In summary, our rapid and highly sensitive sensor offers a novel approach for the detection of sarcosine in real samples, facilitating early prostate cancer diagnosis. Communicated by Ramaswamy H. Sarma

Harnessing fluorescent carbon quantum dots from natural resource for advancing sweat latent fingerprint recognition with machine learning algorithms for enhanced human identification.

Nowadays, it is fascinating to engineer waste biomass into functional valuable nanomaterials. We investigate the production of hetero-atom doped carbon quantum dots (N-S@MCDs) to address the adaptability constraint in green precursors concerning the contents of the green precursors i.e., Tagetes erecta (marigold extract). The successful formation of N-S@MCDs as described has been validated by distinct analytical characterizations. As synthesized N-S@MCDs successfully incorporated on corn-starch powder, providing a nano-carbogenic fingerprint powder composition (N-S@MCDs/corn-starch phosphors). N-S@MCDs imparts astounding color-tunability which enables highly fluorescent fingerprint pattern developed on different non-porous surfaces along with immediate visual enhancement under UV-light, revealing a bright sharp fingerprint, along with long-time preservation of developed fingerprints. The creation and comparison of latent fingerprints (LFPs) are two key research in the recognition and detection of LFPs, respectively. In this work, developed fingerprints are regulated with an artificial intelligence program. The optimum sample has a very high degree of similarity with the standard control, as shown by the program's good matching score (86.94%) for the optimal sample. Hence, our results far outperform the benchmark attained using the conventional method, making the N-S@MCDs/corn-starch phosphors and the digital processing program suitable for use in real-world scenarios.

Lemon peel-based fluorescent carbon quantum dots as a functional filler in polyvinyl alcohol-based films for active packaging applications

Carbonation of agro-waste into high-value-added products is becoming a promising strategy for producing functional active materials and for reducing landfills. Carbon quantum dots (CQDs) are of great attention due to their non-toxic, antibacterial, antioxidant, fluorescent, and other functional properties. The current study demonstrated the hydrothermal synthesis of dried lemon peel-based carbon quantum dots (LCQDs) and their incorporation in polyvinyl alcohol for developing active films. The developed LCQDs exhibit excellent fluorescence, antioxidant, and antibacterial activities against S. aureus, B. cereus, S. enterica, L. monocytogenes, and E. coli. Interestingly, as confirmed by FE-SEM and FTIR, LCQDs showed excellent compatibility with PVA-based films. The mechanical and water vapor barrier properties were improved by adding 3% LCQDs to the PVA film, which also resulted in improved UVC (99.9%), UVB (99.9%) and UVA (99.1%) blocking effects. Additionally, PVA film containing 3% LCQDs showed 98.9% radical scavenging activity by ABTS method and was 100% effective against S. aureus and S. enterica. Therefore, 3% LCQDs-incorporated PVA films could have excellent potential as active food packaging materials.

Recent Advancements in Biomedical Research on Fluorescent Carbon Quantum Dots

Recent Advancements in Biomedical Research on Fluorescent Carbon Quantum Dots

A brief review on the nanomaterials-based detection of CKD biomarkers

Chronic kidney disease (CKD) imposes a significant worldwide medical burden, exacerbated by the often limited efficacy of current treatments. The future prevention and management of CKD critically rely on early detection and effective intervention. Nanomaterials (NMs), such as fluorescence carbon dots (CDs), quantum dots (QDs), and metal-based NMs, emerge as unique and highly sensitive probe materials expected to play a substantial role in the precise identification of CKD biomarkers. NMs’ design makes it possible to manage properties including size, shape, charge, and targeting ligands, which enhances the biological compatibility and availability of medicines. Consequently, the rise of NMs in medicine has brought about fresh approaches to CKD diagnosis. This review explores the utility of the NMs for the rapid identification of CKD biomarkers.

Green transformation of biomass-derived Indian gooseberry into fluorescent intrinsic nitrogen-functionalized carbon quantum dots for real-time detection of vitamin B2 in the nanomolar range

Selective and specific detection of vitamin B2 with a fluorescent nanoprobe synthesized using a green methodology.

Green synthesis of lactic acid and carbon dots using food waste and seashell waste

Novel utilisation of seashell waste in lactic acid fermentation, showcasing fluorescent carbon quantum dots synthesised from cell biomass.

Green synthesis of fluorescent carbon quantum dots from bagasse: inhibition of calcium sulphate scales

The conversion of biomass waste generated in large amounts to value-added materials and energy can reduce environmental pollution, atmospheric CO2 emissions and waste disposal costs in a circular economy.

Recent advancements towards the green synthesis of carbon quantum dots as an innovative and eco-friendly solution for metal ion sensing and monitoring

An overview of the importance of green chemistry in synthesizing fluorescent carbon quantum dots as an effective tool for metal ion sensing is discussed. Various synthesis methods and mechanisms involved in metal ion sensing using CQDs are presented.

A portable smartphone platform based on fluorescent carbon quantum dots derived from biowaste for on-site detection of permanganate

A schematic illustration of the synthesis pathway of CQDs and their application in MnO4− sensing based on a smartphone-assisted platform is shown.

A novel fluorescent traceable carbon quantum dots with selective antibacterial activity against Porphyromonas gingivalis.

Antibiotics can kill bacteria, but their continued use can easily lead to drug resistance, particularly the main pathogenic bacteria of periodontitis, Porphyromonas gingivalis. However, to avoid drug resistance, carbon quantum dots (CDs) have great potential as a bioactive material in antimicrobial therapy. Herein, we use ornidazole as raw material to prepare CDs of different sizes by microwave irradiation and screen CDs with fluorescence and bacteriostatic properties. The inhibition experiments and live/dead assays of P. gingivalis exhibited outstanding antibacterial effects. This research aimed to develop nano-level antibacterial active materials that also have fluorescence traceability. This study offers a different method for the development of multifunctional CDs, provides valuable strategies for the treatment of diseases associated with P. gingivalis, and predicts great application prospects in the field of biomedicine.

Green fabrication of fluorescent N-doped carbon quantum dots from Aegle marmelos leaves for highly selective detection of Fe3+ metal ions

This current study uses a simple, environmentally friendly, and economically advantageous Microwave method to create water-soluble carbon dots from Aegle marmelos leaves. Nitrogen-doped carbon dots (N-CQDs) that have been produced exhibit outstanding benefits such as water solubility, biocompatibility, and high stability. Essential characterization methods are used to examine it, including XRD, FTIR, HR-TEM, XPS, UV–vis, and fluorescence spectroscopy. It exhibits excitation-dependent emission behavior, blue emission under UV lamp illumination (wavelength 365 nm), and pH independence. Synthesized N-CQDs with a quantum yield of 14.21 % responded exceptionally well to Fe3+ ions, which causes fluorescence to quench. A single probe fluorescence-based system for detecting Fe3+ ions with high selectivity and sensitivity was designed. Under optimized fluorescence experimental conditions, the linear range of Fe3+ ions was 0–20 μM with a detection limit of 0.184 µM (R2 = 0.99363). The produced N-CQDs respond exceptionally well to Fe3+ ions, which causes fluorescence to quench. This study demonstrates a single probe FL-based device for detecting Fe3+ ions with high sensitivity and selectivity.

Preparation of a Novel Green Fluorescent Carbon Quantum Dots and Application in Fe3+-Specific Detection in Biological System

Preparation of a Novel Green Fluorescent Carbon Quantum Dots and Application in Fe3+-Specific Detection in Biological System

Construction of optical dual-mode sensing platform based on green emissive carbon quantum dots for effective detection of ClO- and cellular imaging

Hypochlorite (ClO-) is an important redox regulator in reactive oxygen species, which play a considerable role in oxidative stress and related diseases. Hence, accurate and sensitive monitoring of ClO- concentration was urgently needed in the fields of life sciences, food and environment. Bright green fluorescent carbon quantum dots (G-CQDs) were synthesized utilizing one-step hydrothermal method with citric acid and acriflavine precursors. Through TEM, FTIR, XPS and zeta potential characterization procedures, G-CQDs illustrated uniformly dispersed and significant number of –NH2 and –OH on the surface. Meanwhile, the fluorescence and colorimetric analysis exhibited wide linear range and low detection limit response to ClO-. The fluorescence changes of G-CQDs were identified via smartphone to realize mobile sensing of ClO-. Subsequently, G-CQDs was applied for visualization and quantitative detection of ClO- in drinking water samples with satisfactory recovery rate. More importantly, G-CQDs demonstrated good water solubility, optical stability and excellent biocompatibility, which offered a promising analysis approach in cell imaging and exogenous ClO- detection in living cells. G-CQDs illustrated bright prospect and great potential in practical application of ClO- associated disease prevention and early clinical diagnosis.

Withdrawn: 'Facile Synthesis of Nitrogen-Doped Fluorescent Carbon Quantum Dots and the Application in Buprofezin Detection' by Mingyue Xu, Qinghao Liu, Long Xie, Jinchun Guo, Luminescence (https://doi.org/10.1002/bio.4545).

The above article, published online on 24 June 2023 in Wiley Online Library (https://onlinelibrary.wiley.com/doi/10.1002/bio.4545) has been withdrawn by agreement between the journal's Editor in Chief, Dong Wang, and John Wiley & Sons Ltd. The withdrawal has been agreed following no response from the author to requests to sign the Journal's publishing license.

Facile synthesis of highly fluorescent nitrogen-doped carbon quantum dots and their role in bioimaging of some pathogenic microorganisms

Facile synthesis of highly fluorescent nitrogen-doped carbon quantum dots and their role in bioimaging of some pathogenic microorganisms

Synthesis of diethylenetriamine-modified carbon quantum dots for dual sensing Fe3+ and Co2+and its application

Surface modification is an important method for regulating the carbon quantum dots structure and enhancing the performance. Herein, green fluorescent carbon quantum dots (G-CQDs) were synthesized by the solvothermal method using p-phenylenediamine as carbon source, diethylenetriamine as modifier and anhydrous ethanol as solvent. G-CQDs were characterized by TEM, FTIR, XPS, UV–Vis absorption spectroscopy, fluorescence spectroscopy and Zeta potential. The particle size of G-CQDs was about 2.11 nm and the fluorescence quantum yield of G-CQDs was increased from 1.07 % to 28.90 % after diethylenetriamine modification. The increase of nitrogen and oxygen contents after modification enriches the oxygen-containing and nitrogen-containing groups on the surface, providing more reaction sites for metal ions. It was further found that G-CQDs can detect Fe3+ and Co2+ based on two different fluorescence “on-off” mechanisms with detection limits of 0.88 μM and 0.95 μM, respectively. In practical applications, the excellent fluorescence performance of G-CQDs for information anti-counterfeiting has a good effect. It was used for the detection of Fe3+ and Co2+ in tap water, the spike recovery were in the range of 98.11 % ∼ 106.80 % and 95.87 % ∼ 104.49 %, respectively, showing good accuracy and reproducibility.