scholarly journals Recent Developments in Carbon Quantum Dots: Properties, Fabrication Techniques, and Bio-Applications

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 388
Author(s):  
Rehan M. El-Shabasy ◽  
Mohamed Farouk Elsadek ◽  
Badreldin Mohamed Ahmed ◽  
Mohamed Fawzy Farahat ◽  
Khaled N. Mosleh ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Green Synthesis ◽  
Graphene Quantum Dots ◽  
Carbon Sources ◽  
Carbon Quantum Dots ◽  
Synthesis Methods ◽  
Wide Range ◽  
Recent Developments ◽  
Potential Applications ◽  
Harsh Conditions

Carbon dots have gained tremendous interest attributable to their unique features. Two approaches are involved in the fabrication of quantum dots (Top-down and Bottom-up). Most of the synthesis methods are usually multistep, required harsh conditions, and costly carbon sources that may have a toxic effect, therefore green synthesis is more preferable. Herein, the current review presents the green synthesis of carbon quantum dots (CQDs) and graphene quantum dots (GQDs) that having a wide range of potential applications in bio-sensing, cellular imaging, and drug delivery. However, some drawbacks and limitations are still unclear. Other biomedical and biotechnological applications are also highlighted.

scholarly journals Carbon Based Nanodots in Early Diagnosis of Cancer

2021 ◽  
Vol 9 ◽  
Author(s):  
Gurpal Singh ◽  
Harinder Kaur ◽  
Akanksha Sharma ◽  
Joga Singh ◽  
Hema Kumari Alajangi ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Early Stage ◽  
Imaging Techniques ◽  
Graphene Quantum Dots ◽  
Carbon Quantum Dots ◽  
Diagnostic Methods ◽  
Early Diagnosis Of Cancer ◽  
Successful Treatment Outcome ◽  
Wide Range ◽  
Carbon Based

Detection of cancer at an early stage is one of the principal factors associated with successful treatment outcome. However, current diagnostic methods are not capable of making sensitive and robust cancer diagnosis. Nanotechnology based products exhibit unique physical, optical and electrical properties that can be useful in diagnosis. These nanotech-enabled diagnostic representatives have proved to be generally more capable and consistent; as they selectively accumulated in the tumor site due to their miniscule size. This article rotates around the conventional imaging techniques, the use of carbon based nanodots viz Carbon Quantum Dots (CQDs), Graphene Quantum Dots (GQDs), Nanodiamonds, Fullerene, and Carbon Nanotubes that have been synthesized in recent years, along with the discovery of a wide range of biomarkers to identify cancer at early stage. Early detection of cancer using nanoconstructs is anticipated to be a distinct reality in the coming years.

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 Synthesis of Nitrogen-Doped Lignin/DES Carbon Quantum Dots as a Fluorescent Probe for the Detection of Fe3+ Ions

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1282 ◽  
Author(s):  
Xueqin Jiang ◽  
Yixin Shi ◽  
Xin Liu ◽  
Meng Wang ◽  
Pingping Song ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Carbon Nanomaterials ◽  
Carbon Sources ◽  
Deep Eutectic Solvent ◽  
Carbon Quantum Dots ◽  
Iron Ions ◽  
Green Method ◽  
Nitrogen Doped ◽  
Potential Applications ◽  
Sensitivity And Selectivity

Carbon quantum dots (CQDs) as a rising star of carbon nanomaterials have extensive applications due to their excellent characteristics. In this work, we introduce a simple and green method to prepare nitrogen-doped lignin carbon quantum dots (N-L-CQDs) by using alkali lignin carbon sources and deep eutectic solvent (DES) as solution and nitrogen source. The physiochemical characterization results suggested that N-L-CQDs with diameters ranging from 4 to 12 nm were successfully synthesized. The optical properties data indicated that the as-prepared N-L-CQDs with a quantum yield of 7.95% exhibited excellent optoelectronic properties, excitation-dependent and pH stability. After that, we have investigated the N-L-CQDs used as fluorescent probes to detect iron ions, which suggested that the as-prepared N-L-CQDs exhibited excellent sensitivity and selectivity for Fe3+ with a detection limit of 0.44 μM. Besides, cytotoxicity of N-L-CQDs was also evaluated by MTT assay. These results demonstrated that the as-prepared N-L-CQDs with excellent properties have potential applications in environment and biomedicine.

scholarly journals TiO2–Graphene Quantum Dots Nanocomposites for Photocatalysis in Energy and Biomedical Applications

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 319
Author(s):  
Anuja Bokare ◽  
Sowbaranigha Chinnusamy ◽  
Folarin Erogbogbo
Keyword(s):  
Quantum Dots ◽  
Biomedical Applications ◽  
Wearable Sensors ◽  
Graphene Quantum Dots ◽  
Superior Performance ◽  
Synthesis Methods ◽  
Widespread Application ◽  
Wide Range ◽  
Multifunctional Nanocomposites ◽  
Energy Conversion Devices

The focus of current research in material science has shifted from “less efficient” single-component nanomaterials to the superior-performance, next-generation, multifunctional nanocomposites. TiO2 is a widely used benchmark photocatalyst with unique physicochemical properties. However, the large bandgap and massive recombination of photogenerated charge carriers limit its overall photocatalytic efficiency. When TiO2 nanoparticles are modified with graphene quantum dots (GQDs), some significant improvements can be achieved in terms of (i) broadening the light absorption wavelengths, (ii) design of active reaction sites, and (iii) control of the electron-hole (e−-h+) recombination. Accordingly, TiO2-GQDs nanocomposites exhibit promising multifunctionalities in a wide range of fields including, but not limited to, energy, biomedical aids, electronics, and flexible wearable sensors. This review presents some important aspects of TiO2-GQDs nanocomposites as photocatalysts in energy and biomedical applications. These include: (1) structural formulations and synthesis methods of TiO2-GQDs nanocomposites; (2) discourse about the mechanism behind the overall higher photoactivities of these nanocomposites; (3) various characterization techniques which can be used to judge the photocatalytic performance of these nanocomposites, and (4) the application of these nanocomposites in biomedical and energy conversion devices. Although some objectives have been achieved, new challenges still exist and hinder the widespread application of these nanocomposites. These challenges are briefly discussed in the Future Scope section of this review.

scholarly journals Synthesis and optical properties of AgInS2 nanoparticles

2019 ◽  
pp. 12-19
Author(s):  
Y. Gelchuk ◽  
O. Boreiko ◽  
G. Okrepka ◽  
Yu. Khalavka
Keyword(s):  
Quantum Dots ◽  
Colloidal Synthesis ◽  
Synthesis Methods ◽  
Bifunctional Molecules ◽  
Lead And Cadmium ◽  
Spectral Bands ◽  
Wide Range ◽  
Cadmium Chalcogenides ◽  
Potential Applications ◽  
High Boiling Solvent

Ternary chalcogenide Ag-In quantum dots (QDs) are more environmentally friendly than known Cd-, Pb- and P-containing nanoparticles. Here we review the literature on colloidal synthesis methods, properties, and promising fields for the application of AgInS2 quantum dots. Similar to the QDs of lead and cadmium chalcogenides, the most accurate control over the structure and morphology of AgInS2 QDs is achieved by using the method of introducing precursors into high-boiling organic solvents. However, to realize the potential applications of ternary quantum dots, in particular as luminescent biomarkers, the quantum dots must be soluble in polar solvents, especially water. The transfer of quantum dots into aqueous solutions is usually accomplished by exchanging primary lyophilic ligands with smaller bifunctional molecules, such as thioglycolic (or mercapto­propionic) acids, which can passivate the surface of the quantum dots while making them soluble in the polar environment. Methods of colloidal synthesis of AgInS2 / ZnS quantum dots can be classified into the following types: Injection of ions into a high-boiling solvent Synthesis in a mixture of solvents Synthesis in the aquatic environment Methods for the synthesis of AgInS2 QDs in both aqueous solution and organic solvent medium are described. Examples of application of quantum dots for biomedical purposes and in photovoltaic and sensory devices are given. Quantum dots have high photostability and brightness, are characterized by a wide range of absorption and narrow spectral bands of radiation, ie meet most of the criteria for fluorescent materials and biosensors for imaging cancer cells in antitumor therapy, immunofluorescent labeling of proteins, detection of toxins s, visualize intracellular structures, etc. Quantum dots of tertiary chalcogenides, in particular CuInS2 and AgInS2, may be an alternative to quantum dots of binary lead and cadmium chalcogenides for use in light-emitting and light-absorbing systems, such as LEDs, sensors and solar absorbers.

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.

A sustainable green synthesis of functionalized biocompatible carbon quantum dots from Aloe barbadensis miller and its multifunctional applications

2021 ◽  
pp. 111414
Author(s):  
Jalaja Prasad Malavika ◽  
Chellappan Shobana ◽  
Murugesan Ragupathi ◽  
Ponnuchamy Kumar ◽  
Yun Sung Lee ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Green Synthesis ◽  
Carbon Quantum Dots ◽  
Aloe Barbadensis

scholarly journals Sporulation in solventogenic and acetogenic clostridia

2021 ◽  
Author(s):  
Mamou Diallo ◽  
Servé W. M. Kengen ◽  
Ana M. López-Contreras
Keyword(s):  
Current Knowledge ◽  
Carbon Sources ◽  
Cost Effective ◽  
Biotechnological Production ◽  
Key Points ◽  
Wide Range ◽  
Potential Applications ◽  
A Cell ◽  
Sporulation Initiation ◽  
Solventogenic Clostridia

AbstractThe Clostridium genus harbors compelling organisms for biotechnological production processes; while acetogenic clostridia can fix C1-compounds to produce acetate and ethanol, solventogenic clostridia can utilize a wide range of carbon sources to produce commercially valuable carboxylic acids, alcohols, and ketones by fermentation. Despite their potential, the conversion by these bacteria of carbohydrates or C1 compounds to alcohols is not cost-effective enough to result in economically viable processes. Engineering solventogenic clostridia by impairing sporulation is one of the investigated approaches to improve solvent productivity. Sporulation is a cell differentiation process triggered in bacteria in response to exposure to environmental stressors. The generated spores are metabolically inactive but resistant to harsh conditions (UV, chemicals, heat, oxygen). In Firmicutes, sporulation has been mainly studied in bacilli and pathogenic clostridia, and our knowledge of sporulation in solvent-producing or acetogenic clostridia is limited. Still, sporulation is an integral part of the cellular physiology of clostridia; thus, understanding the regulation of sporulation and its connection to solvent production may give clues to improve the performance of solventogenic clostridia. This review aims to provide an overview of the triggers, characteristics, and regulatory mechanism of sporulation in solventogenic clostridia. Those are further compared to the current knowledge on sporulation in the industrially relevant acetogenic clostridia. Finally, the potential applications of spores for process improvement are discussed.Key Points• The regulatory network governing sporulation initiation varies in solventogenic clostridia.• Media composition and cell density are the main triggers of sporulation.• Spores can be used to improve the fermentation process.

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 Organic dots (O-dots) for theranostic applications: preparation and surface engineering

RSC Advances ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 2253-2291
Author(s):  
Amin Shiralizadeh Dezfuli ◽  
Elmira Kohan ◽  
Sepand Tehrani Fateh ◽  
Neda Alimirzaei ◽  
Hamidreza Arzaghi ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Photodynamic Therapy ◽  
Photothermal Therapy ◽  
Biomedical Applications ◽  
Surface Engineering ◽  
Graphene Quantum Dots ◽  
Carbon Quantum Dots ◽  
Cargo Delivery ◽  
Bio Imaging ◽  
Theranostic Applications

Organic dots is a term used to represent materials including graphene quantum dots and carbon quantum dots because they rely on the presence of other atoms (O, H, and N) for their photoluminescence or fluorescence properties. Cargo delivery, bio-imaging, photodynamic therapy and photothermal therapy are major biomedical applications of organic dots.

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