Search query: Carbon quantum dots

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abstract: Fluorescent carbon nanoparticles or carbon quantum dots (CQDs) are a new class of carbon nanomaterials that have emerged recently and have garnered much interest as potential competitors to conventional semiconductor quantum dots. In addition to their comparable optical properties, CQDs have the desired advantages of low toxicity, environmental friendliness low cost and simple synthetic routes. Moreover, surface passivation and functionalization of CQDs allow for the control of their physicochemical properties. Since their discovery, CQDs have found many applications in the fields of chemical sensing, biosensing, bioimaging, nanomedicine, photocatalysis and electrocatalysis. This article reviews the progress in the research and development of CQDs with an emphasis on their synthesis, functionalization and technical applications along with some discussion on challenges and perspectives in this exciting and promising field.
author_names: Shi Ying Lim

Wei Shen

Zhiqiang Gao
title: Carbon quantum dots and their applications.
venue: Chemical Society reviews
year: 2015

abstract: Strategies for selectively imaging and delivering drugs to tumours typically leverage differentially upregulated surface molecules on cancer cells. Here, we show that intravenously injected carbon quantum dots, functionalized with multiple paired a carboxyl and amino groups that bind to the large neutral amino acid transporter 1 (which is expressed in most tumours) selectively accumulate in human tumour xenografts in mice and in an orthotopic mouse model of human glioma. The functionalized quantum dots, which structurally mimic large amino acids and can be loaded with aromatic drugs through p p stacking interactions, enabled in the absence of detectable toxicity near infrared fluorescence and photoacoustic imaging of the tumours and a reduction in tumour burden after the targeted delivery of chemotherapeutics to the tumours. The versatility of functionalization and high tumour selectivity of the quantum dots make them broadly suitable for tumour specific imaging and drug delivery. Intravenously injected functionalized carbon quantum dots that bind to the large neutral amino acid transporter 1 and that structurally mimic large amino acids selectively accumulate in human tumours in mice, facilitating targeted theranostics.
author_names: Shuhua Li

Wen Su

Hao Wu

Ting Yuan

Chang Yuan

Jun Liu

Gang Deng

Xingchun Gao

Zeming Chen

Youmei Bao

Fanglong Yuan

Shixin Zhou

Hongwei Tan

Yunchao Li

Xiaohong Li

Louzhen Fan

Jia Zhu

Ann Tai Chen

Fuyao Liu

Yu Zhou

Miao Li

Xingchen Zhai

Jiangbing Zhou
title: Targeted tumour theranostics in mice via carbon quantum dots structurally mimicking large amino acids
venue: Nature Biomedical Engineering
year: 2020

abstract: Carbon quantum dots (CQDs) as an emerging class of quantum dots (QDs) with advantages such as good photoluminescence (PL) properties, easy synthesis routes, economical synthesis, cheap starting materials, water solubility, low levels of toxicity, chemical stability, and easy functionalization have received great attention during recent years. CQDs have been used in versatile sensor applications. CQD sensors could be ultimately sensitive, and the limit of detection (LOD) for these sensors can reach the nanomolar, picomolar or even femtomolar ranges. CQD based sensors and biosensors work with different mechanisms including fluorescence quenching, static quenching, dynamic quenching, energy transfer, inner filter effect (IFE) photo induced electron transfer (PET) and fluorescence resonance energy transfer (FRET) CQD based sensors and biosensors have been applied for the detection of different species such as metal ions, acids, proteins, biothiols, polypeptides, DNA and miRNA, water pollutants, hematin, drugs, vitamins, and other chemicals. It seems that CQD based sensors and biosensors are promising candidates for high performance and yet accurate sensors in different areas. In this review, CQDs are introduced, and the synthesis methods and optical properties of CQDs are discussed. Different types of CQD based sensors and biosensors and their working mechanisms are clarified.
author_names: Mohammad Jafar Molaei
title: Principles, mechanisms, and application of carbon quantum dots in sensors: a review
year: 2020

abstract: Efficient full color fluorescent carbon quantum dots are synthesized by acid reagent engineering for white light emitting devices. Quantum dots have innate advantages as the key component of optoelectronic devices. For white light emitting diodes (WLEDs) the modulation of the spectrum and color of the device often involves various quantum dots of different emission wavelengths. Here, we fabricate a series of carbon quantum dots (CQDs) through a scalable acid reagent engineering strategy. The growing electron withdrawing groups on the surface of CQDs that originated from acid reagents boost their photoluminescence wavelength red shift and raise their particle sizes, elucidating the quantum size effect. These CQDs emit bright and remarkably stable full color fluorescence ranging from blue to red light and even white light. Full color emissive polymer films and all types of high color rendering index WLEDs are synthesized by mixing multiple kinds of CQDs in appropriate ratios. The universal electron donating/withdrawing group engineering approach for synthesizing tunable emissive CQDs will facilitate the progress of carbon based luminescent materials for manufacturing forward looking films and devices.
author_names: Liang Wang

Weitao Li

Luqiao Yin

Yijiang Liu

Huazhang Guo

Jiawei Lai

Yu Han

Gao Li

Ming Li

Jianhua Zhang

Robert Vajtai

Pulickel M Ajayan

Minghong Wu
title: Full color fluorescent carbon quantum dots
venue: Science Advances
year: 2020

abstract: Abstract Currently, the disposal of municipal wastes (paper, plastic, and coffee residue) is a problem due to increasing the amount of municipal wastes, global environmental problems, and high disposal cost. Here, we report the synthesis of carbon quantum dots from waste paper by different solvents by a conventional hydro /solvothermal method for solving the environmental and disposal problems. The carbon quantum dots synthesized with waste papers have several advantages such as low toxicity, low cost, and eco friendly. The prepared carbon quantum dots have main emission peak from 440 to 540 nm under 340 480 nm excitation. The prepared carbon quantum dots can be applied to easily prepare anti counterfeiting ink and fluorescent flexible film because of their unique optical property and excellent chemical and photostability.
author_names: Sung Jun Park

Jin Young Park

Jong Won Chung

Hyun Kyoung Yang

Byung Kee Moon

Soung Soo Yi
title: Color tunable carbon quantum dots from wasted paper by different solvents for anti counterfeiting and fluorescent flexible film
year: 2020

abstract: Large doses of anticancer drugs entering cancer cell nuclei are found to be effective at killing cancer cells and increasing chemotherapeutic effectiveness. Here we report red emissive carbon quantum dots, which can enter into the nuclei of not only cancer cells but also cancer stem cells. After doxorubicin was loaded at the concentration of 30 mg/mL on the surfaces of carbon quantum dots, the average cell viability of HeLa cells was decreased to only 21% while it was decreased to 50% for free doxorubicin. The doxorubicin loaded carbon quantum dots also exhibited a good therapeutic effect by eliminating cancer stem cells. This work provides a potential strategy for developing carbon quantum dot based anticancer drug carriers for effective eradication of cancers.
author_names: Wen Su

Ruihua Guo

Fanglong Yuan

Yunchao Li

Xiaohong Li

Yang Zhang

Shixin Zhou

Louzhen Fan
title: Red Emissive Carbon Quantum Dots for Nuclear Drug Delivery in Cancer Stem Cells.
venue: The journal of physical chemistry letters
year: 2020

abstract: Carbon and graphene quantum dots are prepared using top down and bottom up methods. Sustainable synthesis of quantum dots has several advantages such as the use of low cost and non toxic raw materials, simple operations, expeditious reactions, renewable resources and straightforward post processing steps. These nanomaterials are promising for clinical and biomedical sciences, especially in bioimaging, diagnosis, bioanalytical assays and biosensors. Here we review green methods for the fabrication of quantum dots, and biomedical and biotechnological applications.
author_names: Siavash Iravani

Rajender S Varma
title: Green synthesis, biomedical and biotechnological applications of carbon and graphene quantum dots. A review
venue: Environmental Chemistry Letters
year: 2020

abstract: Nitrogen doped carbon quantum dots (N CQDs) were successfully synthesized using rice residue and glycine as carbon and nitrogen sources by one step hydrothermal method. High quantum yield (23.48% originated from the effective combination of nitrogen with various functional groups (CO, NH, CN, COOH and COC) The N CQDs showed a fluorescence with the wavelength varied from 420 to 500 nm and the maximum emission wavelength being at 440 nm. N CQDs have been importantly applied as probe to detect Fe3+ and tetracycline (TCs) antibiotics with remarkable performance. Using the linear relationship between fluorescence intensity and Fe3+ concentration, the N CQDs could be employed as a simple, efficient sensor for ultrasensitive Fe3+ detection ranging from 3.32 to 32.26 uM, with a limit of detection (LOD) of 0.7462 uM. The N CQDs showed the applicability to detect TCs. The detection limits of tetracycline, terramycin and chlortetracycline were 0.2367, 0.3739 and 0.2791 uM, respectively. The results of TC by fluorescence method in real water samples were in good agreement with standard Ultraviolet visible (UV vis) method. The N CQDs have various potential applications including sensitive and selective detection of Fe3+ and TCs, and cellular imaging with low cytotoxicity, good biocompatibility and high permeability.
author_names: Houjuan Qi

Min Teng

Miao Liu

Shouxin Liu

Jian Li

Haipeng Yu

Chunbo Teng

Zhanhua Huang

Hu Liu

Qian Shao

Ahmad Umar

Tao Ding

Qiang Gao

Zhanhu Guo
title: Biomass derived nitrogen doped carbon quantum dots: highly selective fluorescent probe for detecting Fe3+ ions and tetracyclines.
venue: Journal of colloid and interface science
year: 2019

abstract: Therapeutic options for the highly pathogenic human coronavirus (HCoV) infections are urgently needed. Anticoronavirus therapy is however challenging, as coronaviruses are biologically diverse and rapidly mutating. In this work, the antiviral activity of seven different carbon quantum dots (CQDs) for the treatment of human coronavirus HCoV 229E infections was investigated. The first generation of antiviral CQDs was derived from hydrothermal carbonization of ethylenediamine/citric acid as carbon precursors and postmodified with boronic acid ligands. These nanostructures showed a concentration dependent virus inactivation with an estimated EC50 of 52 8 mg mL 1. CQDs derived from 4 aminophenylboronic acid without any further modification resulted in the second generation of anti HCoV nanomaterials with an EC50 lowered to 5.2 0.7 mg mL 1. The underlying mechanism of action of these CQDs was revealed to be inhibition of HCoV 229E entry that could be due to interaction of the functional groups of the CQDs with HCoV 229E entry receptors; surprisingly, an equally large inhibition activity was observed at the viral replication step.
author_names: Aleksandra Loczechin

Karin Seron

Alexandre Barras

Emerson Giovanelli

Sandrine Belouzard

Yen-Ting Chen

Nils Metzler-Nolte

Rabah Boukherroub

Jean Dubuisson

Sabine Szunerits
title: Functional Carbon Quantum Dots as Medical Countermeasures to Human Coronavirus
venue: ACS applied materials interfaces
year: 2019

abstract: Abstract Microbial contamination and antibiotic pollutions diffusely exist in wastewater system, and contaminated water poses a threat to public health. Therefore, there is a need to effectively remove biohazard and antibiotic contamination from wastewater systems. In this paper, sulfur doped carbon quantum dots (S CQDs)/hollow tubular g C3N4 photocatalyst (HTCN C) prepared via ultrasonic assisted synthesis strategy, was regarded as an efficient catalyst for the degradation of antibiotic (tetracycline) and destruction of a typical Gram negative bacterium (Escherichia coli) in imitated wastewater system. The unique structures of hollow tubular g C3N4 and loading of modified carbon quantum dots enhanced electron transfer and charge separation, leading to a significant improvement in photocatalytic efficiency. Benefiting from these merits, the optimized catalysts (HTCN C(2) exhibited superior performance with a reaction rate of 0.0293 min 1 for tetracycline (TC) degradation and 99.99% destruction of Escherichia coli under visible light irradiation. Moreover, the characterization of UV Vis diffuse reflectance spectra, photoluminescence technique, transient photocurrent responses and electrochemical impedance spectroscopy also verified the good optical and electrochemical properties of resultant samples. Our current work indicates that HTCN C has great potential in degradation of antibiotic and destruction of bacterium for practical wastewater treatment.
author_names: Wenjun Wang

Zhuotong Zeng

Guangming Zeng

Chen Zhang

Rong Xiao

Chengyun Zhou

Weiping Xiong

Yongxiang Yang

Lei Lei

Yang Liu

Danlian Huang

Min Cheng

Ya-Ya Yang

Yukui Fu

Hanzhuo Luo

Yin Zhou
title: Sulfur doped carbon quantum dots loaded hollow tubular g C3N4 as novel photocatalyst for destruction of Escherichia coli and tetracycline degradation under visible light
year: 2019