Fabrication of carbon quantum dots/1D MoO3-x hybrid junction with enhanced LED light efficiency in photocatalytic inactivation of E. coli and S. aureus

2020 ◽  
Vol 836 ◽  
pp. 155410 ◽  
Author(s):  
Yeping Li ◽  
Chaobao Wang ◽  
Liying Huang ◽  
Fei Zhang ◽  
Hao Wang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Carbon Quantum Dots ◽  
Led Light ◽  
E Coli ◽  
Photocatalytic Inactivation ◽  
Hybrid Junction ◽  
Light Efficiency

scholarly journals P-Doped Carbon Quantum Dots with Antibacterial Activity

Micromachines ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1116
Author(s):  
Shuiqin Chai ◽  
Lijia Zhou ◽  
Shuchen Pei ◽  
Zhiyuan Zhu ◽  
Bin Chen
Keyword(s):  
Quantum Dots ◽  
Antibacterial Activity ◽  
Bacterial Infections ◽  
Fluorescence Emission ◽  
Carbon Quantum Dots ◽  
Microbial Pathogens ◽  
Electronic Interaction ◽  
Minimal Inhibitory Concentrations ◽  
E Coli ◽  
Zeta Potential Analysis

It is a major challenge to effectively inhibit microbial pathogens in the treatment of infectious diseases. Research on the application of nanomaterials as antibacterial agents has evidenced their great potential for the remedy of infectious disease. Among these nanomaterials, carbon quantum dots (CQDs) have attracted much attention owing to their unique optical properties and high biosafety. In this work, P-doped CQDs were prepared by simple hydrothermal treatment of m-aminophenol and phosphoric acid with fluorescence emission at 501 nm when excited at 429 nm. The P-doped CQDs showed effective antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The minimal inhibitory concentrations (MICs) of P-doped CQD were 1.23 mg/mL for E. coli and 1.44 mg/mL for S. aureus. Furthermore, the morphologies of E. coli cells were damaged and S. aureus became irregular when treated with the P-doped CQDs. The results of zeta potential analysis demonstrated that the P-doped CQDs inhibit antibacterial activity and destroy the structure of bacteria by electronic interaction. In combination, the results of this study indicate that the as-prepared P-doped CQDs can be a promising candidate for the treatment of bacterial infections.

scholarly journals Synergy between “Probiotic” Carbon Quantum Dots and Ciprofloxacin in Eradicating Infectious Biofilms and Their Biosafety in Mice

Pharmaceutics ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1809
Author(s):  
Yanyan Wu ◽  
Guang Yang ◽  
Henny C. van der Mei ◽  
Linqi Shi ◽  
Henk J. Busscher ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Open Space ◽  
Carbon Quantum Dots ◽  
Probiotic Bacteria ◽  
Ros Generation ◽  
E Coli ◽  
Protein Levels ◽  
Reactive Protein ◽  
Physico Chemical ◽  
Intestinal Infections

Orally administrated probiotic bacteria can aid antibiotic treatment of intestinal infections, but their arrival at their intestinal target site is hampered by killing in the gastrointestinal tract and by antibiotics solely intended for pathogen killing. Carbon-quantum-dots are extremely small nanoparticles and can be derived from different sources, including bacteria. Here, we hypothesize that carbon-quantum-dots inherit antibacterial activity from probiotic source bacteria to fulfill a similar role as live probiotics in intestinal infection therapy. Physico-chemical analyses indicated that carbon-quantum-dots, hydrothermally derived from Bifidobacterium breve (B-C-dots), inherited proteins and polysaccharides from their source-bacteria. B-C-dots disrupted biofilm matrices of Escherichia coli and Salmonella typhimurium biofilms through extensive reactive-oxygen-species (ROS)-generation, causing a decrease in volumetric bacterial-density in biofilms. Decreased bacterial densities leave more open space in biofilms and have enhanced ciprofloxacin penetration and killing potential in an E. coli biofilm pre-exposed to probiotic B-C-dots. Pathogenic carbon-quantum-dots hydrothermally derived from E. coli (E-C-dots) did not disrupt pathogenic biofilms nor enhance E. coli killing potential by ciprofloxacin. B-C-dots were biosafe in mice upon daily administration, while E-C-dots demonstrated a decrease in white blood cell and platelet counts and an increase in C-reactive protein levels. Therefore, the way is paved for employing probiotic carbon-quantum-dots instead of viable, probiotic bacteria for synergistic use with existing antibiotics in treating intestinal infections.

scholarly journals Photocatalytic inactivation of Escherichia coli under UV light irradiation using large surface area anatase TiO 2 quantum dots

2019 ◽  
Vol 6 (12) ◽  
pp. 191444
Author(s):  
Faheem Ahmed ◽  
Chawki Awada ◽  
Sajid Ali Ansari ◽  
Abdullah Aljaafari ◽  
Adil Alshoaibi
Keyword(s):  
Escherichia Coli ◽  
Quantum Dots ◽  
Specific Surface ◽  
Band Gap ◽  
Surface Area ◽  
Ultraviolet Light ◽  
Light Irradiation ◽  
Rapid Synthesis ◽  
E Coli ◽  
Photocatalytic Inactivation

In this study, high specific surface areas (SSAs) of anatase titanium dioxide (TiO 2 ) quantum dots (QDs) were successfully synthesized through a novel one-step microwave–hydrothermal method in rapid synthesis time (20 min) without further heat treatment. XRD analysis and HR-TEM images showed that the as-prepared TiO 2 QDs of approximately 2 nm size have high crystallinity with anatase phase. Optical properties showed that the energy band gap ( E g ) of as-prepared TiO 2 QDs was 3.60 eV, which is higher than the standard TiO 2 band gap, which might be due to the quantum size effect. Raman studies showed shifting and broadening of the peaks of TiO 2 QDs due to the reduction of the crystallite size. The obtained Brunauer–Emmett–Teller specific surface area (381 m 2 g −1 ) of TiO 2 QDs is greater than the surface area (181 m 2 g −1 ) of commercial TiO 2 nanoparticles. The photocatalytic activities of TiO 2 QDs were conducted by the inactivation of Escherichia coli under ultraviolet light irradiation and compared with commercially available anatase TiO 2 nanoparticles. The photocatalytic inactivation ability of E. coli was estimated to be 91% at 60 µg ml −1 for TiO 2 QDs, which is superior to the commercial TiO 2 nanoparticles. Hence, the present study provides new insight into the rapid synthesis of TiO 2 QDs without any annealing treatment to increase the absorbance of ultraviolet light for superior photocatalytic inactivation ability of E. coli .

Efficient photocatalytic inactivation of E. coli by Mn-CdS/ZnCuInSe/CuInS2 quantum dots-sensitized TiO2 nanowires

2020 ◽  
Vol 31 (39) ◽  
pp. 395602
Author(s):  
Hongchao Geng ◽  
Ning Jiang ◽  
Chenyi Li ◽  
Xingqi Zhu ◽  
Yan Qiao ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Tio2 Nanowires ◽  
E Coli ◽  
Photocatalytic Inactivation ◽  
Cuins2 Quantum Dots

A simple one-step hydrothermal route towards water solubilization of carbon quantum dots from soya-nuggets for imaging applications

RSC Advances ◽  
2015 ◽  
Vol 5 (106) ◽  
pp. 87528-87534 ◽  
Author(s):  
Prashant Dubey ◽  
Kumud Malika Tripathi ◽  
Ragini Mishra ◽  
Anshu Bhati ◽  
Anupriya Singh ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Hydrothermal Process ◽  
Carbon Quantum Dots ◽  
Single Step ◽  
Water Soluble ◽  
High Yield ◽  
Synthetic Approach ◽  
Hydrothermal Route ◽  
E Coli ◽  
One Step

A high yield simple synthetic approach for water soluble photoluminescent carbon quantum dots via a single step, hydrothermal process, was described. Photoluminescent multi-colored emissions were used to label E. coli cells.

scholarly journals Potential Military Cotton Textiles by Carbon Quantum Dots

2021 ◽  
Author(s):  
Hossam E. Emam ◽  
Mahmoud El-Shahat ◽  
Mohamed S. Hasanin ◽  
Hanan B. Ahmed
Keyword(s):  
Staphylococcus Aureus ◽  
Quantum Dots ◽  
Carbon Quantum Dots ◽  
Cotton Fabrics ◽  
Protection Factor ◽  
Yellowness Index ◽  
E Coli ◽  
Microbial Inhibition ◽  
Blocking Activity ◽  
Fluorescence Peak

Abstract Owing to the sensitivity for color vicissitude by exposing to UV irradiation, manufacturing of fluorescent fabrics is widely demanded to be exploited in camping, sensing and military purposes. Pyrimidine based heterocycles were investigated with excellent pharmacological activity, however, their photoluminescence activity was never been investigated till now. The presented approach demonstrate a quite novel route for manufacturing of potential military textiles (fluorescent/UV-protective cotton fabrics with micobicide activity) via exploitation of carbon quantum dots (CQDs) nucleated from pyrimidine based heterocycle (4-(2,4-dichlorophenyl)-6-oxo-2-thioxohexahydropyrimidine-5-carbonitrile, Target Molecule, TM). The synthesized TM & CQDs were separately immobilized within both of native and cationized cotton fabrics to obtain TM@cotton, CQDs@cotton, TM@Q-cotton and CQDs@Q-cotton fabrics. The estimated yellowness index, intensity of the fluorescence peak, UV-blocking activity and microbicide action, were all followed the order of CQDs@Q-cotton > TM@Q-cotton > CQDs@cotton > TM @cotton. CQDs@Q-cotton showed quite good durability, as after 5 washings, yellowness index was diminished from 26.5 to only 20.3, florescence intensity for CQDs@Q-cotton was decreased from 540 nm to 340 nm and transmission percent was increased from 7 % to 10 %. Moreover, even after 10 washings, microbial inhibition (as a percent) against E. coli, Staphylococcus aureus and Candida albicans was estimated to 63 %, 68 % and 67 %, respectively, while, UV protection factor (UPF) was diminished from 38.2 (very good) to 21.5 (good). The presented unique route was succeeded for manufacturing of durable fluorescent textiles that could be superiorly applied as potential military textiles.

LUMINESCENT DETERMINATION OF SUGAR IN NATURAL HONEY

2020 ◽  
Vol 0 (4) ◽  
pp. 29-32
Author(s):  
B.M. GAREEV ◽  
◽  
A.M. ABDRAKHMANOV ◽  
G.L. SHARIPOV ◽  
◽  
...  
Keyword(s):  
Quantum Dots ◽  
Laboratory Test ◽  
Aqueous Solutions ◽  
Analytical Method ◽  
Sugar Content ◽  
Carbon Quantum Dots ◽  
Photoluminescence Intensity ◽  
Sucrose Content ◽  
Natural Honey

The photoluminescence of carbon quantum dots synthesized from natural honey and mixtures of honey and sugar has been studied. An increase in the sugar content leads to a decrease in the photoluminescence intensity without changing the shape of the luminescence spectrum of these quantum dots aqueous solutions, which is associated with a decrease in the yield of their synthesis in the sugar presence. The discovered effect can be used to detect sugar in honey. When examining five different market samples of flower honey using this method, two of them showed a significant decrease in the photoluminescence intensity. A laboratory test for compliance with GOST 19792-2017 Standard requirements established an excess of the sucrose content in these samples. Luminescent determination of sugar in honey does not require complicated equipment and can be used to develop a new analytical method for determining the sugar content in counterfeit natural honey.

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