scholarly journals A Novel Fluorescent Test Papers Based on Carbon Dots for Selective and Sensitive Detection of Cr (VI)

2020 ◽  
Vol 8 ◽  
Author(s):  
Yizhou Yang ◽  
Xuemei Chen ◽  
Yangyang Wang ◽  
Miao Wu ◽  
Yinan Ma ◽  
...  
Keyword(s):  
Carbon Dots ◽  
Average Diameter ◽  
Hydrothermal Carbonization ◽  
Fluorescence Probes ◽  
Excitation Wavelength ◽  
Tetraacetic Acid ◽  
Yellow Fluorescence ◽  
Lower Detection Limit ◽  
Lower Detection ◽  
One Step

In recent years, carbon dots (CDs) are promising fluorescence probes for ions detection. In this paper, the CDs which are with an average diameter of 5.5 nm were synthesized through a simple one-step hydrothermal carbonization of ethylene diamine tetraacetic acid (EDTA) salt. The CDs have strong yellow photoluminescence (PL) with a maximum emission intensity at 550 nm under an excitation wavelength of 450 nm. As the electron transfer will occur between Cr (VI) and the CDs, yellow fluorescence was quenched after adding the Cr (VI) ions. The CDs probe allows the detection of Cr (VI) ions over a concentration range from 0 to 0.1 M (R2 = 0.987) and the lower detection limit is 10−5 M. Simultaneously, the CDs show highly selectivity and stability toward the detection of Cr (VI) ions.

scholarly journals The Preparation of Green Fluorescence-Emissioned Carbon Dots/Poly(N-Isopropylacrylamide) Temperature-Sensitive Hydrogels and Research on Their Properties

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1171 ◽  
Author(s):  
Dan Zhao ◽  
Wenting Ma ◽  
Rong Wang ◽  
Xinzhou Yang ◽  
Jun Li ◽  
...  
Keyword(s):  
Carbon Dots ◽  
Fluorescence Spectra ◽  
Cell Imaging ◽  
Fluorescence Probes ◽  
Excitation Wavelength ◽  
Temperature Sensitive ◽  
Green Fluorescence ◽  
Microscope Imaging ◽  
One Step ◽  
Good Biocompatibility

Fluorescence/temperature-sensitive hydrogels, thanks to their properties in fluorescence and temperature sensitivity, have shown a promising outlook in the fields of drug delivery, cell imaging, etc., and thus become the focus of present research. This paper reports the preparation of green-fluorescence/temperature-sensitive hydrogels through one-step radical polymerization with green fluorescence-emissioned carbon dots as fluorescence probes and N-isopropylacrylamide as a monomer. UV-vis spectra, fluorescence spectra, and fluorescence microscope imaging have been used to characterize the prepared hydrogel, and to study their optical and temperature-sensitive properties. It was discovered that the emission of prepared hydrogel is excitation wavelength-dependent, pH responding, and excellent temperature-sensitive, as well as having good biocompatibility. The prepared hydrogel can also be applied as fluorescence ink in the fields of anti-counterfeit identification and appraisal.

Nitrogen and sulfur co-doped carbon dots synthesis via one step hydrothermal carbonization of green alga and their multifunctional applications

2019 ◽  
Vol 147 ◽  
pp. 1038-1047 ◽  
Author(s):  
Yuehai Li ◽  
Fengjiao Liu ◽  
Jiabai Cai ◽  
Xuguang Huang ◽  
Luxiu Lin ◽  
...  
Keyword(s):  
Green Alga ◽  
Carbon Dots ◽  
Hydrothermal Carbonization ◽  
One Step ◽  
Doped Carbon Dots ◽  
Co Doped

scholarly journals Manganese-Doped Carbon Dots Via Inner Filter Effect for the Sensitive Detection of Tetracycline in Poultry Meat Samples

2021 ◽  
pp. 38-46
Author(s):  
Ke Su ◽  
Guoqiang Xiang ◽  
Yunlong Zhang ◽  
Xin Wang ◽  
Linhui Wang ◽  
...  
Keyword(s):  
Carbon Dots ◽  
Inner Filter Effect ◽  
Poultry Meat ◽  
Excitation Wavelength ◽  
Ultraviolet Emission ◽  
Characteristic Absorption Peak ◽  
Filter Effect ◽  
One Step ◽  
Meat Samples ◽  
Doped Carbon Dots

In this study, a rapid and sensitive analytical method has been developed to detect tetracycline hydrochloride (TC) using manganese-doped carbon dots (Mn-CDs) prepared by one-step hydrothermal procedure using 1-(2-pyridinylazo)-2-naohthalenol (PAN) and MnCl2 as precursor reagents. The obtained Mn-CDs showed an ultraviolet emission at 360 nm with an excitation wavelength of 300 nm. TC has a strong characteristic absorption peak at 356 nm, which has a large spectral overlap with the emission band of the Mn-CDs. The fluorescence intensity (FI) of Mn-CDs at 360 nm is linearly quenched within the TC concentration range of 0.1-200 µM. The developed assay for the detection of TC was based on an inner filter effect (IFE) mechanism and is rapid, sensitive, and was successfully applied for the determination of TC in different poultry meat samples with satisfactory results.

scholarly journals Hydrothermal Synthesis of Clove Buds-Derived Multifunctional Carbon Dots Passivated with PVP- Antioxidants, Catalysis, and Bioimaging Applications

2021 ◽  
Author(s):  
Anurag Kumar Pandey ◽  
Kamakshi Bankoti ◽  
Tapan Kumar Nath ◽  
Santanu Dhara
Keyword(s):  
Carbon Dots ◽  
Synergetic Effect ◽  
Cost Effective ◽  
Average Diameter ◽  
Fibroblast Cell ◽  
Interlayer Spacing ◽  
Mouse Fibroblast ◽  
Biological Studies ◽  
One Step ◽  
Environmentally Friendly Process

The present study reports a one-step clean synthesis of carbon dots (CDs) using clove buds and polyvinylpyrrolidone (PVP) as the starting precursor via hydrothermal routes. The adopted technique is facile, reproducible, and cost-effective for the production of externally passivated carbon dots owing to an environmentally friendly process utilizing natural precursors. The study evidenced the synergetic effect of passivation on light absorption and fluorescence properties in comparison to non-passivated carbon dots (CCDs). The structural and morphological study revealed that the PVP-passivated clove-derived carbon dots (PPCCDs) were spherical with an average diameter of ~ 2 nm and crystalline with an interlayer spacing of 0.33 nm. The PPCCDs showed excellent antioxidant activity against DPPH free radicals and also showed good catalytic activity for the degradation of Rhodamine-B (Rh-B) dye under studied conditions. Synthesized PPCCDs showed dose-dependent toxicity in L929 (mouse fibroblast) cell lines, while the appropriate concentration used in biological studies was found to be biocompatible as evidenced by MTT assays and also revealed in bioimaging potential. To conclude, synthesised PPCCDs is an economically potent candidate with multifunctional aspects, which can serve as an excellent antioxidant, catalyst, and efficient multicolor bioimaging tool.

scholarly journals Fluorescent N-doped carbon dots from bacterial cellulose for highly sensitive bacterial detection

BioResources ◽  
2019 ◽  
Vol 15 (1) ◽  
pp. 78-88
Author(s):  
Shunli Li ◽  
Xin Zhao ◽  
Yujie Zhang ◽  
Honglei Chen ◽  
Yu Liu
Keyword(s):  
Bacterial Cellulose ◽  
Carbon Dots ◽  
High Performance ◽  
Hydrothermal Carbonization ◽  
Excitation Wavelength ◽  
Particle Sizes ◽  
Bacterial Detection ◽  
Highly Sensitive ◽  
Wide Range ◽  
Doped Carbon Dots

Carbon dots have good dispersion capability, strong visible fluorescence, low toxicity, and photo-induced accepting and donating abilities. Carbon dots were obtained from biomass bacterial cellulose (BC) via one-step hydrothermal carbonization. Effects of hydrothermal time and temperature on the microstructure, fluorescence, and excitation wavelength dependent photoluminescence (PL) behavior were explored for the prepared carbon dots. The results showed that the carbon dots obtained directly from the BC (C dots) had small particle sizes (2.0 to 3.0 nm) and green luminescence behavior. Conversely, the N-doped carbon dots (N-C dots) exhibited more uniform and smaller particle sizes (approximately 1.0 nm), strong blue luminescence, acceptable fluorescence lifetime, and good stability in a wide range of pH values (2.0 to 10.0). Thus, carbon dots could serve as a fluorescent material used in high performance optical cellular imaging and highly sensitive bacterial detection.

scholarly journals A Review of Fluorescent Carbon Dots, Their Synthesis, Physical and Chemical Characteristics, and Applications

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1448
Author(s):  
Mychele Jorns ◽  
Dimitri Pappas
Keyword(s):  
Carbon Dots ◽  
Hydrothermal Carbonization ◽  
Quantitative Information ◽  
Fluorescent Imaging ◽  
Excitation Wavelength ◽  
Cell Type ◽  
Different Types ◽  
Biological Environment ◽  
Physical And Chemical ◽  
Fluorescent Carbon Dots

Carbon dots (CDs) are a particularly useful type of fluorescent nanoparticle that demonstrate biocompatibility, resistance to photobleaching, as well as diversity in composition and characteristics amongst the different types available. There are two main morphologies of CDs: Disk-shaped with 1–3 stacked sheets of aromatic carbon rings and quasi-spherical with a core-shell arrangement having crystalline and amorphous properties. They can be synthesized from various potentially environmentally friendly methods including hydrothermal carbonization, microwaving, pyrolysis or combustion, and are then purified via one or more methods. CDs can have either excitation wavelength-dependent or -independent emission with each having their own benefits in microscopic fluorescent imaging. Some CDs have an affinity for a particular cell type, organelle or chemical. This property allows the CDs to be used as sensors in a biological environment and can even provide quantitative information if the quenching or intensity of their fluorescence is dependent on the concentration of the analyte. In addition to fluorescent imaging, CDs can also be used for other applications including drug delivery, quality control, photodynamic therapy, and photocatalysis.

scholarly journals Highly Fluorescent Carbon Dots as a Potential Fluorescence Probe for Selective Sensing of Ferric Ions in Aqueous Solution

Chemosensors ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 301
Author(s):  
Raji Atchudan ◽  
Somasundaram Chandra Kishore ◽  
Thomas Nesakumar Jebakumar Immanuel Edison ◽  
Suguna Perumal ◽  
Rajangam Vinodh ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Carbon Dots ◽  
Fluorescence Probe ◽  
Synthesis Method ◽  
Blue Emission ◽  
Spherical Shape ◽  
Average Diameter ◽  
Excitation Wavelength ◽  
X Ray ◽  
Fluorescence Characteristics

This paper’s emphasis is on the development of a fluorescent chemosensor for Fe3+ ions in an aqueous solution, using hydrophilic carbon dots (O-CDs). A simple, cost-effective, and environmentally friendly one-step hydrothermal synthesis method was used to synthesize fluorescent hydrophilic O-CDs from Oxalis corniculata (Family; Oxalidaceae). The graphitic structure and size distribution of the O-CDs was verified by X-ray diffraction, Raman spectroscopy, and high-resolution transmission electron microscopy studies. The resulting O-CDs had a near-spherical shape and an adequate degree of graphitization at the core, with an average diameter of 4.5 nm. X-ray photoelectron and Fourier transform infrared spectroscopy methods revealed the presence of several hydrophilic groups (carbonyl, amine, carboxyl, and hydroxyl, along with nitrogen and oxygen-rich molecules) on the surface of O-CDs. The synthesized hydrophilic O-CDs with excitation wavelength-dependent emission fluorescence characteristics showed a high quantum yield of about 20%. Besides this, the hydrophilic O-CDs exhibited a bright and controllable fluorescence with prolonged stability and photo-stability. These fluorescent hydrophilic O-CDs were used as a nanoprobe for the fluorometric identification of Fe3+ ions in an aqueous solution, with high sensitivity and selectivity. By quenching the blue emission fluorescence of this nanosensor, a highly sensitive Fe3+ ion in the range of 10–50 µM with a minimum detection limit of 0.73 µM was achieved. In addition, the developed nanosensor can be used to sense intracellular Fe3+ ions with high biocompatibility and cellular imaging capacity, and it has a lot of potential in biomedical applications.

Controllable Electrochemical Synthesis of Ag Hierarchical Micro/Nanostructures with High SERS-Activity

NANO ◽  
2020 ◽  
Vol 15 (04) ◽  
pp. 2050043
Author(s):  
Huayu Zhou ◽  
Jingjing Wang ◽  
Qiong Yang ◽  
Menglei Chen ◽  
Changsheng Song ◽  
...  
Keyword(s):  
Indium Tin Oxide ◽  
Current System ◽  
Three Dimensional ◽  
Constant Current ◽  
Localized Surface Plasmon ◽  
Excitation Wavelength ◽  
Raman Signal ◽  
Mixed Solution ◽  
Raman Enhancement ◽  
One Step

We report a one-step electrochemical deposition technique to prepare three-dimensional (3D) Ag hierarchical micro/nanostructured film consisting of well-crystallized Ag nanosheets grown on an indium tin oxide (ITO) conductive substrate. The Ag hierarchical micro/nanostructures were fabricated in the mixed solution of AgNO3 and sodium citrate in a constant current system at room temperature. Through reduction of Ag[Formula: see text] electrodeposited on the surface of ITO substrate, nanoparticles were grown to form nanosheets which further combined into 3D sphere-like microstructures. The 3D Ag micro/nanostructures have many sharp edges and nanoscale gaps which can give rise to good Raman-enhanced effect. Due to localized surface plasmon resonance (LSPR) effects, these special Ag micro/nanostructures exhibited good Raman-enhanced performance. Using Rhodamine 6G (R6G) molecules as probe molecule, we studied the influence of excitation wavelength on Raman enhancement. The results showed that the 532[Formula: see text]nm excitation wavelength is the best to obtain the strongest Raman signal and to reduce the influence of other impurity peaks. Using the as-synthesized Ag hierarchical micro/nanostructures, we can detect the 10[Formula: see text][Formula: see text]mol/L R6G aqueous solution, exhibiting great Raman-enhanced effect.

scholarly journals Green Synthesis of Multifunctional Carbon Dots with Antibacterial Activities

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 369 ◽  
Author(s):  
Arumugam Saravanan ◽  
Moorthy Maruthapandi ◽  
Poushali Das ◽  
John H. T. Luong ◽  
Aharon Gedanken
Keyword(s):  
Carbon Dots ◽  
Fluorescence Spectra ◽  
Antibacterial Effect ◽  
Curcuma Longa ◽  
Antibacterial Activities ◽  
Blue Color ◽  
Mean Size ◽  
One Step ◽  
Bactericidal Activities ◽  
Bright Blue

Carbon dots (CDs) were obtained from medicinal turmeric leaves (Curcuma longa) by a facile one-step hydrothermal method and evaluated for their bactericidal activities against two gram-negative; Escherichia coli, Klebsiella pneumoniae, and two gram-positive counterparts; Staphylococcus aureus, S. epidermidis. The CDs exhibited spherical shapes with a mean size of 2.6 nm. The fluorescence spectra of CDs revealed intense fluorescence at λex/em = 362/429 nm with a bright blue color in an aqueous solution. The CDs showed strong photostability under various environmental conditions (pH, salt, and UV-radiation). The complete bactericidal potency of CDs was 0.25 mg/mL for E.coli and S. aureus after 8 h of exposure, while for K. pneumoniae, and S. epidermidis, the CDs at 0.5 mg/mL good antibacterial effect within 8 h and complete eradication after 24 h of exposure is observed. The release of reactive oxygen species played a crucial role in the death of the bacterial cell. The present study provides a strategy for the preparation of CDs from a medicinal plant and their potential antibacterial activities against four common contagious pathogens.

scholarly journals Electrochromic Performance and Capacitor Performance of α-MoO3 Nanorods Fabricated by a One-Step Procedure

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 783
Author(s):  
Ying Duan ◽  
Chen Wang ◽  
Jian Hao ◽  
Yang Jiao ◽  
Yanchao Xu ◽  
...  
Keyword(s):  
Growth Parameters ◽  
Average Diameter ◽  
Fast Response ◽  
Cycle Stability ◽  
Electrochromic Devices ◽  
Step Procedure ◽  
One Step ◽  
Supercapacitor Performance ◽  
First Time ◽  
Prepared Nanorods

In this paper, we propose for the first time the synthesis of α-MoO3 nanorods in a one-step procedure at mild temperatures. By changing the growth parameters, the microstructure and controllable morphology of the resulting products can be customized. The average diameter of the as-prepared nanorods is about 200 nm. The electrochromic and capacitance properties of the synthesized products were studied. The results show that the electrochromic properties of α-MoO3 nanorods at 550 nm have 67% high transmission contrast, good cycle stability and fast response time. The MoO3 nanorods also exhibit a stable supercapacitor performance with 98.5% capacitance retention after 10,000 cycles. Although current density varies sequentially, the nanostructure always exhibits a stable capacitor to maintain 100%. These results indicate the as-prepared MoO3 nanorods may be good candidates for applications in electrochromic devices and supercapacitors.

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