scholarly journals Coumarin-Modified CQDs for Biomedical Applications—Two-Step Synthesis and Characterization

2020 ◽  
Vol 21 (21) ◽  
pp. 8073 ◽  
Author(s):  
Łukasz Janus ◽  
Julia Radwan-Pragłowska ◽  
Marek Piątkowski ◽  
Dariusz Bogdał
Keyword(s):  
Quantum Dots ◽  
Method Development ◽  
Water Solubility ◽  
Hydrothermal Carbonization ◽  
Carbon Quantum Dots ◽  
Raw Material ◽  
Carbon Nanodots ◽  
Waste Biomass ◽  
Xtt Assay ◽  
Fluorescence Characteristics

Waste biomass such as lignin constitutes a great raw material for eco-friendly carbon quantum dots (CQDs) synthesis, which find numerous applications in various fields of industry and medicine. Carbon nanodots, due to their unique luminescent properties as well as water-solubility and biocompatibility, are superior to traditional organic dyes. Thus, obtainment of CQDs with advanced properties can contribute to modern diagnosis and cell visualization method development. In this article, a new type of coumarin-modified CQD was obtained via a hybrid, two-step pathway consisting of hydrothermal carbonization and microwave-assisted surface modification with coumarin-3-carboxylic acid and 7-(Diethylamino) coumarin-3-carboxylate. The ready products were characterized over their chemical structure and morphology. The nanomaterials were confirmed to have superior fluorescence characteristics and quantum yield up to 18.40%. They also possessed the ability of biomolecules and ion detection due to the fluorescence quenching phenomena. Their lack of cytotoxicity to L929 mouse fibroblasts was confirmed by XTT assay. Moreover, the CQDs were proven over their applicability in real-time bioimaging. Obtained results clearly demonstrated that proposed surface-modified carbon quantum dots may become a powerful tool applicable in nanomedicine and pharmacy.

scholarly journals Facile Synthesis of Surface-Modified Carbon Quantum Dots (CQDs) for Biosensing and Bioimaging

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3313 ◽  
Author(s):  
Łukasz Janus ◽  
Julia Radwan-Pragłowska ◽  
Marek Piątkowski ◽  
Dariusz Bogdał
Keyword(s):  
Quantum Dots ◽  
Chemical Structure ◽  
Water Solubility ◽  
Organic Dyes ◽  
Carbon Quantum Dots ◽  
Raw Material ◽  
The Novel ◽  
Surface Modified ◽  
Synthesis Approach ◽  
Effective Analysis

Recently, fluorescent probes became one of the most efficient tools for biosensing and bioimaging. Special attention is focused on carbon quantum dots (CQDs), which are characterized by the water solubility and lack of cytotoxicity. Moreover, they exhibit higher photostability comparing to traditional organic dyes. Currently, there is a great need for the novel, luminescent nanomaterials with tunable properties enabling fast and effective analysis of the biological samples. In this article, we propose a new, ecofriendly bottom-up synthesis approach for intelligent, surface-modified nanodots preparation using bioproducts as a raw material. Obtained nanomaterials were characterized over their morphology, chemical structure and switchable luminescence. Their possible use as a nanodevice for medicine was investigated. Finally, the products were confirmed to be non-toxic to fibroblasts and capable of cell imaging.

scholarly journals N-Doped Carbon Quantum Dots as Fluorescent Bioimaging Agents

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 789
Author(s):  
Shih-Fu Ou ◽  
Ya-Yun Zheng ◽  
Sin-Jen Lee ◽  
Shyi-Tien Chen ◽  
Chien-Hui Wu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Carbon Nanomaterials ◽  
Graphene Quantum Dots ◽  
Carbon Quantum Dots ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Fluorescence Characteristics ◽  
And Staphylococcus Aureus

Graphene quantum dots, carbon nanomaterials with excellent fluorescence characteristics, are advantageous for use in biological systems owing to their small size, non-toxicity, and biocompatibility. We used the hydrothermal method to prepare functional N-doped carbon quantum dots (N-CQDs) from 1,3,6-trinitropyrene and analyzed their ability to fluorescently stain various bacteria. Our results showed that N-CQDs stain the cell septa and membrane of the Gram-negative bacteria Escherichia coli, Salmonellaenteritidis, and Vibrio parahaemolyticus and the Gram-positive bacteria Bacillus subtilis, Listeria monocytogenes, and Staphylococcus aureus. The optimal concentration of N-CQDs was approximately 500 ppm for Gram-negative bacteria and 1000 ppm for Gram-positive bacteria, and the exposure times varied with bacteria. N-Doped carbon quantum dots have better light stability and higher photobleaching resistance than the commercially available FM4-64. When excited at two different wavelengths, N-CQDs can emit light of both red and green wavelengths, making them ideal for bioimaging. They can also specifically stain Gram-positive and Gram-negative bacterial cell membranes. We developed an inexpensive, relatively easy, and bio-friendly method to synthesize an N-CQD composite. Additionally, they can serve as a universal bacterial membrane-staining dye, with better photobleaching resistance than commercial dyes.

scholarly journals Formation of Carbon Quantum Dots via Hydrothermal Carbonization: Investigate the Effect of Precursors

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 986
Author(s):  
Md Rifat Hasan ◽  
Nepu Saha ◽  
Thomas Quaid ◽  
M. Toufiq Reza
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Microcrystalline Cellulose ◽  
Uv Light ◽  
Synthesis Method ◽  
Hydrothermal Carbonization ◽  
Carbon Quantum Dots ◽  
Medical Diagnostics ◽  
Particle Size Range ◽  
Wide Range

Carbon quantum dots (CQDs) are nanomaterials with a particle size range of 2 to 10 nm. CQDs have a wide range of applications such as medical diagnostics, bio-imaging, biosensors, coatings, solar cells, and photocatalysis. Although the effect of various experimental parameters, such as the synthesis method, reaction time, etc., have been investigated, the effect of different feedstocks on CQDs has not been studied yet. In this study, CQDs were synthesized from hydroxymethylfurfural, furfural, and microcrystalline cellulose via hydrothermal carbonization at 220 °C for 30 min of residence time. The produced CQDs showed green luminescence behavior under the short-wavelength UV light. Furthermore, the optical properties of CQDs were investigated using ultraviolet-visible spectroscopy and emission spectrophotometer, while the morphology and chemical bonds of CQDs were investigated using transmission electron microscopy and Fourier-transform infrared spectroscopy, respectively. Results showed that all CQDs produced from various precursors have absorption and emission properties but these optical properties are highly dependent on the type of precursor. For instance, the mean particle sizes were 6.36 ± 0.54, 5.35 ± 0.56, and 3.94 ± 0.60 nm for the synthesized CQDs from microcrystalline cellulose, hydroxymethylfurfural, and furfural, respectively, which appeared to have similar trends in emission intensities. In addition, the synthesized CQDs experienced different functionality (e.g., C=O, O-H, C-O) resulting in different absorption behavior.

scholarly journals The Application of Green-Synthesis-Derived Carbon Quantum Dots to Bioimaging and the Analysis of Mercury(II)

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Qianchun Zhang ◽  
Xiaolan Zhang ◽  
Linchun Bao ◽  
Yun Wu ◽  
Li Jiang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Hela Cells ◽  
Photoelectron Spectroscopy ◽  
Water Solubility ◽  
Limit Of Detection ◽  
Carbon Quantum Dots ◽  
Coefficient Of Determination ◽  
Serum Samples ◽  
X Ray ◽  
Transmission Electron

Ginkgo leaves were used as precursors for the hydrothermal synthesis of carbon quantum dots (CQDs), which were subsequently characterized by transmission electron microscopy as well as Fourier-transform infrared, X-ray powder diffraction, and X-ray photoelectron spectroscopy. The prepared CQDs exhibited a fluorescence quantum yield of 11% and superior water solubility and fluorescence stability, as well as low cytotoxicities and excellent biocompatibilities with A549 and HeLa cells; these CQDs were also used to bioimage HeLa cells. Moreover, owing to the experimental observation that Hg2+ quenches the fluorescence of the CQDs in a specific and sensitive manner, we developed a method for the detection of Hg2+ using this fluorescence sensor. The sensor exhibited a linear range for Hg2+ of 0.50–20 μM, with an excellent coefficient of determination (R2 = 0.9966) and limit of detection (12.4 nM). In practice, the proposed method was shown to be highly selective and sensitive for the monitoring of Hg2+ in lake water and serum samples.

Design of carbon quantum dots via hydrothermal carbonization synthesis from renewable precursors

2019 ◽  
Vol 9 (4) ◽  
pp. 689-694 ◽  
Author(s):  
M. F. Gomes ◽  
Y. F. Gomes ◽  
A. Lopes-Moriyama ◽  
E. L. de Barros Neto ◽  
Carlson Pereira de Souza
Keyword(s):  
Quantum Dots ◽  
Hydrothermal Carbonization ◽  
Carbon Quantum Dots

scholarly journals Recent Advancements in Doped/Co-Doped Carbon Quantum Dots for Multi-Potential Applications

2019 ◽  
Vol 5 (2) ◽  
pp. 24 ◽  
Author(s):  
Ganeshlenin Kandasamy
Keyword(s):  
Quantum Dots ◽  
Optical Sensors ◽  
Carbon Nanomaterials ◽  
Synthesis Method ◽  
Carbon Quantum Dots ◽  
Carbon Nanodots ◽  
Synthesis Methods ◽  
Sensing Applications ◽  
Potential Applications ◽  
Co Doped

Carbon quantum dots (CQDs)/carbon nanodots are a new class of fluorescent carbon nanomaterials having an approximate size in the range of 2–10 nm. The majority of the reported review articles have discussed about the development of the CQDs (via simple and cost-effective synthesis methods) for use in bio-imaging and chemical-/biological-sensing applications. However, there is a severe lack of consolidated studies on the recently developed CQDs (especially doped/co-doped) that are utilized in different areas of application. Hence, in this review, we have extensively discussed about the recent development in doped and co-doped CQDs (using elements/heteroatoms—e.g., boron (B), fluorine (F), nitrogen (N), sulphur (S), and phosphorous (P)), along with their synthesis method, reaction conditions, and/or quantum yield (QY), and their emerging multi-potential applications including electrical/electronics (such as light emitting diode (LED) and solar cells), fluorescent ink for anti-counterfeiting, optical sensors (for detection of metal ions, drugs, and pesticides/fungicides), gene delivery, and temperature probing.

scholarly journals An Alternative Route to Obtain Carbon Quantum Dots from Photoluminescent Materials in Peat

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1492 ◽  
Author(s):  
Rafael Souza da Costa ◽  
Wiliam Ferreira da Cunha ◽  
Nizamara Simenremis Pereira ◽  
Artemis Marti Ceschin
Keyword(s):  
Quantum Dots ◽  
Aromatic Compounds ◽  
Elemental Carbon ◽  
Low Cost ◽  
Carbon Quantum Dots ◽  
Raw Material ◽  
Transmission Electron ◽  
Photoluminescent Materials ◽  
Average Size ◽  
Green Coloration

Peat, an organic compound easily found in the soil (easy to acquire), has more than 50% elemental carbon in its composition and can be used as raw material to produce carbon quantum dots (CQDs, C-dots, Carbon Dots). In this work we describe two simple and low-cost routes for the acquisition of these photoluminescent materials based on peat. The final products were characterized by Fourier transform infrared spectroscopy (FTIR), absorption (UV-Vis) and emission (PL) spectra and high-resolution transmission electron microscopy (HRTEM). The produced CQDs have an average size of 3.5 nm and exhibit coloration between blue and green. In addition, it is possible to produce photoluminescence by means of the aromatic compounds also present in the composition of the peat, in turn exhibiting an intense green coloration. The results indicate great versatility of peat for the production of photoluminescent materials.

scholarly journals Polyethylene Glycol6000/carbon Nanodots as Fluorescent Bioimaging Agents

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 677 ◽  
Author(s):  
Chun-Chieh Fu ◽  
Chun-Yung Wu ◽  
Chih-Ching Chien ◽  
Tai-Hao Hsu ◽  
Shih-Fu Ou ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Carbon Quantum Dots ◽  
Carbon Nanodots ◽  
Gram Negative Bacteria ◽  
Fluorescent Properties ◽  
Gram Positive ◽  
Gram Negative ◽  
Different Types ◽  
Living Organisms ◽  
Surface Modified

Photoluminescent nanomaterials have immense potential for use in biological systems due to their excellent fluorescent properties and small size. Traditional semiconductor quantum dots are heavy-metal-based and can be highly toxic to living organisms, besides their poor photostability and low biocompatibility. Nano-sized carbon quantum dots and their surface-modified counterparts have shown improved characteristics for imaging purposes. We used 1,3, 6-trinitropyrene (TNP) and polyethylene glycol6000 (PEG6000) in a hydrothermal method to prepare functional polyethylene glycol6000/carbon nanodots (PEG6000/CDs) and analyzed their potential in fluorescent staining of different types of bacteria. Our results demonstrated that PEG6000/CDs stained the cell pole and septa of gram-positive bacteria B. Subtilis and B. thuringiensis but not those of gram-negative bacteria. The optimal concentration of these composite nanodots was approximately 100 ppm and exposure times varied across different bacteria. The PEG6000/CD composite had better photostability and higher resistance to photobleaching than the commercially available FM4-64. They could emit two wavelengths (red and green) when exposed to two different wavelengths. Therefore, they may be applicable as bioimaging molecules. They can also be used for differentiating different types of bacteria owing to their ability to differentially stain gram-positive and gram-negative bacteria.

Green Synthetic Fluorescent Carbon Quantum Dot as pH Sensor Applied to Real Water Samples Determination

NANO ◽  
2021 ◽  
pp. 2150093
Author(s):  
Yong Zhang ◽  
Sijie Cheng ◽  
Yanteng Xiao ◽  
Yingte Wang
Keyword(s):  
Water Samples ◽  
Water Solubility ◽  
Ph Sensor ◽  
Blue Emission ◽  
Carbon Quantum Dots ◽  
Raw Material ◽  
Narrow Particle Size Distribution ◽  
Ph Response ◽  
Real Water Samples ◽  
One Step

Willow, a common tree species, is mainly distributed in temperate regions of the Northern Hemisphere. Catkins are the seeds of willow. In addition to propagating new willows, it is of great significance to study its application in other areas. Carbon quantum dots (CQDs) have attracted extensive attention owing to their excellent luminescence properties, low toxicity and water solubility. The use of CQDs for accurate measurement of pH is of great significance in environmental, medical and other fields. Based on this, blue-emission fluorescent CQDs with 4.93% quantum yield (Q.Y.) are prepared via natural product catkins as the only raw material by one-step hydrothermal method. The prepared CQDs exhibit excellent water solubility, narrow particle size distribution, excitation-dependent photoluminescence properties and sensitive pH response behavior. The fluorescence intensity of CQDs has a good linear relationship with pH in the range of 6–12, and the correlation coefficient is 0.994. In addition, the CQDs have good stability, and the response to pH displays excellent reversibility, which can be developed as a pH sensor to quantitatively monitor the pH values in real water samples. Thereby, the potential practical application is promising.

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