Graphene quantum dots for the inhibition of β amyloid aggregation

Nanoscale ◽  
2015 ◽  
Vol 7 (45) ◽  
pp. 19060-19065 ◽  
Author(s):  
Yibiao Liu ◽  
Li-Ping Xu ◽  
Wenhao Dai ◽  
Haifeng Dong ◽  
Yongqiang Wen ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Amyloid Aggregation ◽  
Aβ Peptides ◽  
Β Amyloid ◽  
Low Cytotoxicity

GQDs, efficient and low-cytotoxicity inhibitors, are reported for their application in inhibiting the aggregation of Aβ peptides.

scholarly journals Modulation of β-amyloid aggregation by graphene quantum dots

2019 ◽  
Vol 6 (6) ◽  
pp. 190271 ◽  
Author(s):  
Changliang Liu ◽  
Huan Huang ◽  
Lilusi Ma ◽  
Xiaocui Fang ◽  
Chen Wang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Structural Changes ◽  
Graphene Quantum Dots ◽  
Amyloid Peptide ◽  
Therapeutic Drug ◽  
Amyloid Aggregation ◽  
Β Amyloid ◽  
Regulatory Effects ◽  
Β Amyloid Peptide

Misfolding and abnormal aggregation of β-amyloid peptide is associated with the onset and progress of Alzheimer's disease (AD). Therefore, modulating β-amyloid aggregation is critical for the treatment of AD. Herein, we studied the regulatory effects and mechanism of graphene quantum dots (GQDs) on 1–42 β-amyloid (Aβ 1–42 ) aggregation. GQDs displayed significant regulatory effects on the aggregation of Aβ 1–42 peptide as detected by thioflavin T (ThT) assay. Then, the changes of confirmations and structures induced by GQDs on the Aβ 1–42 aggregation were monitored by circular dichroism (CD), dynamic light scattering (DLS) and transmission electron microscope (TEM). The in vitro cytotoxicity experiments further demonstrated the feasibility of GQDs on the regulation of Aβ 1–42 aggregation. Meanwhile, the structural changes of a Aβ 1–42 /GQDs mixture in different pH revealed that electrostatic interaction was the major driving force in the co-assembly process of Aβ 1–42 and GQDs. The proposed mechanism of the regulatory effects of GQDs on the Aβ 1–42 aggregation was also deduced reasonably. This work not only demonstrated the potential feasibility of GQDs as therapeutic drug for AD but also clarified the regulatory mechanism of GQDs on the Aβ 1–42 aggregation.

scholarly journals One-Step Synthesis of Diamine-Functionalized Graphene Quantum Dots from Graphene Oxide and Their Chelating and Antioxidant Activities

Nanomaterials ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 104 ◽  
Author(s):  
Rabeb El-Hnayn ◽  
Laetitia Canabady-Rochelle ◽  
Christophe Desmarets ◽  
Lavinia Balan ◽  
Hervé Rinnert ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Graphene Oxide ◽  
Colloidal Stability ◽  
Antioxidant Activities ◽  
Graphene Quantum Dots ◽  
Average Diameter ◽  
Functionalized Graphene ◽  
One Step ◽  
Low Cytotoxicity ◽  
Health Applications

2,2’-(Ethylenedioxy)bis(ethylamine)-functionalized graphene quantum dots (GQDs) were prepared under mild conditions from graphene oxide (GO) via oxidative fragmentation. The as-prepared GQDs have an average diameter of ca. 4 nm, possess good colloidal stability, and emit strong green-yellow light with a photoluminescence (PL) quantum yield of 22% upon excitation at 375 nm. We also demonstrated that the GQDs exhibit high photostability and the PL intensity is poorly affected while tuning the pH from 1 to 8. Finally, GQDs can be used to chelate Fe(II) and Cu(II) cations, scavenge radicals, and reduce Fe(III) into Fe(II). These chelating and reducing properties that associate to the low cytotoxicity of GQDs show that these nanoparticles are of high interest as antioxidants for health applications.

Recent Advances in the Cancer Bioimaging with Graphene Quantum Dots

2018 ◽  
Vol 25 (25) ◽  
pp. 2876-2893 ◽  
Author(s):  
Keheng Li ◽  
Xinna Zhao ◽  
Gang Wei ◽  
Zhiqiang Su
Keyword(s):  
Quantum Dots ◽  
Biomedical Applications ◽  
Cell Imaging ◽  
Graphene Quantum Dots ◽  
Biological Properties ◽  
Live Cells ◽  
Physical Chemical ◽  
Specific Cancer ◽  
Good Biocompatibility ◽  
Low Cytotoxicity

Fluorescent graphene quantum dots (GQDs) have attracted increasing interest in cancer bioimaging due to their stable photoluminescence (PL), high stability, low cytotoxicity, and good biocompatibility. In this review, we present the synthesis and chemical modification of GQDs firstly, and then introduce their unique physical, chemical, and biological properties like the absorption, PL, and cytotoxicity of GQDs. Finally and most importantly, the recent applications of GQDs in cancer bioimaging are demonstrated in detail, in which we focus on the biofunctionalization of GQDs for specific cancer cell imaging and real-time molecular imaging in live cells. We expect this work would provide valuable guides on the synthesis and modification of GQDs with adjustable properties for various biomedical applications in the future.

Multifunctional carbon dots as a therapeutic nanoagent for modulating Cu(ii)-mediated β-amyloid aggregation

Nanoscale ◽  
2019 ◽  
Vol 11 (13) ◽  
pp. 6297-6306 ◽  
Author(s):  
You Jung Chung ◽  
Byung Il Lee ◽  
Chan Beum Park
Keyword(s):  
Carbon Dots ◽  
Amyloid Aggregation ◽  
Aβ Peptides ◽  
Aβ Aggregation ◽  
Amyloid Aβ ◽  
Β Amyloid

Multifunctional carbon dots are synthesized to chelate Cu(ii) ions, suppress Alzheimer's β-amyloid (Aβ) aggregation, and photooxygenate Aβ peptides.

scholarly journals Carbon-Based Quantum Dots for Electrochemical Detection of Monoamine Neurotransmitters—Review

Biosensors ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 162
Author(s):  
Saheed E. Elugoke ◽  
Abolanle S. Adekunle ◽  
Omolola E. Fayemi ◽  
Bhekie B. Mamba ◽  
El-Sayed M. Sherif ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Electrochemical Sensors ◽  
Graphene Quantum Dots ◽  
Good Sensitivity ◽  
Health Issues ◽  
Monoamine Neurotransmitters ◽  
Good Electrocatalytic Activity ◽  
Low Cytotoxicity ◽  
Made In ◽  
Carbon Based

Imbalance in the levels of monoamine neurotransmitters have manifested in severe health issues. Electrochemical sensors have been designed for their determination, with good sensitivity recorded. Carbon-based quantum dots have proven to be an important component of electrochemical sensors due to their high conductivity, low cytotoxicity and opto-electronic properties. The quest for more sensitive electrodes with cheaper materials led to the development of electrochemical sensors based on carbon-based quantum dots for the detection of neurotransmitters. The importance of monoamine neurotransmitters (NTs) and the good electrocatalytic activity of carbon and graphene quantum dots (CQDs and GQDs) make the review of the efforts made in the design of such sensors for monoamine NTs of huge necessity. The differences and the similarities between these two quantum dots are highlighted prior to a discussion of their application in electrochemical sensors over the last ten years. Compared to other monoamine NTs, dopamine (DA) was the most studied with GQDs and CQD-based electrochemical sensors.

High-Purity Amino-Functionalized Graphene Quantum Dots Derived from Graphene Hydrogel

NANO ◽  
2016 ◽  
Vol 11 (12) ◽  
pp. 1650138 ◽  
Author(s):  
Yinhua Jin ◽  
Hongyi Qin ◽  
Jang Ah Kim ◽  
Sun-Young Kim ◽  
Hyeong-U Kim ◽  
...  
Keyword(s):  
Quantum Dots ◽  
High Purity ◽  
Hydrothermal Reaction ◽  
Graphene Quantum Dots ◽  
Synthesis Method ◽  
Water Soluble ◽  
Synthesis Process ◽  
Functionalized Graphene ◽  
Ultrasonic Probe ◽  
Low Cytotoxicity

The unique properties of graphene quantum dots (GQDs) make them interesting candidate materials for innovative applications. Herein, we report a facile method to synthesize amino-functionalized graphene quantum dots (AF-GQDs) by a hydrothermal reaction. Graphene oxide (GO) was synthesized by Hummer’s method where ultra-small GO sheets were obtained by a prolonged oxidation process followed by sonication using an ultrasonic probe. Subsequently, graphene hydrogel (GH) was also obtained by a hydrothermal synthesis method. Proper care was taken during synthesis to avoid contamination from water soluble impurities, which are present in the precursor, GO solution. Following the treatment of GH in ammonia, ultra-small amino-functionalized graphene fragments (AF-GQDs) were formed, which detached from the GH to eventually disperse evenly in the water without agglomerating. This modified synthesis process enables the formation of high-purity AF-GQDs (99.14%) while avoiding time-consuming synthesis procedures. Our finding shows that AF-GQDs with sizes less than 5[Formula: see text]nm were well dispersed. A strong photoluminescence (PL) emission at [Formula: see text]410[Formula: see text]nm with 10% PL quantum yield was also observed. These AF-GQDs can be used in many bio applications in view of their low cytotoxicity and strong fluorescence that can be applied to cell imaging.

scholarly journals Rapid synthesis of graphene quantum dots using a continuous hydrothermal flow synthesis approach

RSC Advances ◽  
2017 ◽  
Vol 7 (24) ◽  
pp. 14716-14720 ◽  
Author(s):  
Suela Kellici ◽  
John Acord ◽  
Nicholas P. Power ◽  
David J. Morgan ◽  
Paolo Coppo ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Environmentally Benign ◽  
Rapid Synthesis ◽  
Flow Synthesis ◽  
Benign Synthesis ◽  
Low Cytotoxicity ◽  
Green Fluorescent ◽  
Synthesis Approach ◽  
Hydrothermal Flow

A rapid and environmentally benign synthesis of green fluorescent graphene quantum dots (GQD) with low cytotoxicity via Continuous Hydrothermal Flow Synthesis (CHFS) aided by calix[4]arene tetrasulfonic acid (SCX4) as a particle size limiting agent.

scholarly journals Unravelling the Potential of Graphene Quantum Dots in Biomedicine and Neuroscience

2020 ◽  
Vol 21 (10) ◽  
pp. 3712 ◽  
Author(s):  
Giordano Perini ◽  
Valentina Palmieri ◽  
Gabriele Ciasca ◽  
Marco De Spirito ◽  
Massimiliano Papi
Keyword(s):  
Drug Delivery ◽  
Quantum Dots ◽  
Optical Properties ◽  
Graphene Quantum Dots ◽  
Chemotherapeutic Drugs ◽  
The Central Nervous System ◽  
Low Cytotoxicity ◽  
Theranostic Applications ◽  
The Brain ◽  
Neuroimaging Techniques

Quantum dots (QDs) are semiconducting nanoparticles that have been gaining ground in various applications, including the biomedical field, thanks to their unique optical properties. Recently, graphene quantum dots (GQDs) have earned attention in biomedicine and nanomedicine, thanks to their higher biocompatibility and low cytotoxicity compared to other QDs. GQDs share the optical properties of QD and have proven ability to cross the blood-brain barrier (BBB). For this reason, GQDs are now being employed to deepen our knowledge in neuroscience diagnostics and therapeutics. Their size and surface chemistry that ease the loading of chemotherapeutic drugs, makes them ideal drug delivery systems through the bloodstream, across the BBB, up to the brain. GQDs-based neuroimaging techniques and theranostic applications, such as photothermal and photodynamic therapy alone or in combination with chemotherapy, have been designed. In this review, optical properties and biocompatibility of GQDs will be described. Then, the ability of GQDs to overtake the BBB and reach the brain will be discussed. At last, applications of GQDs in bioimaging, photophysical therapies and drug delivery to the central nervous system will be considered, unraveling their potential in the neuroscientific field.

Fluorine Functionalized Graphene Quantum Dots as Inhibitor against hIAPP Amyloid Aggregation

2017 ◽  
Vol 8 (6) ◽  
pp. 1368-1377 ◽  
Author(s):  
Maryam Yousaf ◽  
Huan Huang ◽  
Ping Li ◽  
Chen Wang ◽  
Yanlian Yang
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Functionalized Graphene ◽  
Amyloid Aggregation

N,S Co-Doped Graphene Quantum Dots for Detection of Riboflavin and Cell Imaging

NANO ◽  
2021 ◽  
pp. 2150123
Author(s):  
Mengting Zhang ◽  
Xiaorong Li ◽  
Hong Xiao ◽  
Bin Zhao ◽  
Wei Bian
Keyword(s):  
Quantum Dots ◽  
Cell Imaging ◽  
Graphene Quantum Dots ◽  
Practical Application ◽  
X Ray ◽  
Pyrolysis Method ◽  
Doped Graphene ◽  
Low Cytotoxicity ◽  
Bright Blue Fluorescence ◽  
Bright Blue

Graphene quantum dots (GQDs) have been extensively used in biosensors and bioimaging. Heteroatom-doped GQDs can regulate material properties and endow them to improve structural and physicochemical properties. In this work, N,S-GQDs were prepared through a high-temperature pyrolysis method using L-cysteine and citric acid as the precursors. The morphology and structure of nanocomposites were identified by TEM, X-ray diffractometer (XRD), X-ray photoelectron spectrometer (XPS), and FTIR. The as-prepared N,S-GQDs show bright blue fluorescence with satisfactory fluorescence quantum yield. N,S-GQDs display significant response to riboflavin, achieving a low detection limit of 27[Formula: see text]nM. The reaction of N,S-GQDs to riboflavin is mainly governed by static quenching. The detection of riboflavin in real samples has been performed to demonstrate its practical application. The obtained N,S-GQDs have low cytotoxicity and have been applied successfully in cell imaging.

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