1
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Villamayor N, Villaseñor MJ, Ríos Á. Selective dual sensing strategy for free and vitamin D 3 micelles in food samples based on S,N-GQDs photoinduced electron transfer. Anal Bioanal Chem 2024; 416:4173-4191. [PMID: 38795215 DOI: 10.1007/s00216-024-05344-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Revised: 05/13/2024] [Accepted: 05/16/2024] [Indexed: 05/27/2024]
Abstract
A reliable nanotechnological sensing strategy, based on an S,N-co-doped graphene quantum dot (GQD) platform, has been developed to distinctly detect two key variants of vitamin D3, specifically the free (VD3) and the nanoencapsulated form (VD3Ms). For this purpose, food-grade vitamin D3 micelles were self-assembled using a low-energy procedure (droplet size: 49.6 nm, polydispersity index: 0.34, ζ-potential: -33 mV, encapsulation efficiency: 90 %) with an innovative surfactant mixture (Tween 60 and quillaja saponin). Herein, four fluorescent nanoprobes were also synthesized and thoroughly characterized: S,N-co-doped GQDs, α-cyclodextrin-GQDs, β-cyclodextrin-GQDs, and γ-cyclodextrin-GQDs. The goal was to achieve a selective dual sensing strategy for free VD3 and VD3Ms by exploiting their distinctive quenching behaviors. Thus, the four nanosensors allowed the individual sensing of both targets to be performed (except α-CD-GQD for VD3Ms), but S,N-GQDs were finally selected due to selectivity and sensitivity (quantum yield, QY= 0.76) criteria. This choice led to a photoinduced electron transfer (PET) mechanism associated with static quenching, where differentiation was evidenced through a displayed 13-nm hypsochromic (blue) shift when interacting with VD3Ms. The reliability of this dual approach was demonstrated through an extensive evaluation of analytical performance characteristics. The feasibility and accuracy were proven in commercial food preparations and nutritional supplements containing declared nanoencapsulated and raw VD3, whose results were validated by a paired Student's t-test comparison with a UV-Vis method. To the best of our knowledge, this represents the first non-destructive analytical approach addressing the groundbreaking foodomic trend to distinctly detect different bioactive forms of vitamin D3, while also preserving their native nanostructures as a chemical challenge, thus providing reliable information about their final stability and bioavailability.
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Affiliation(s)
- Natalia Villamayor
- Department of Analytical Chemistry and Food Technology, Faculty of Chemical Science and Technology, University of Castilla-La Mancha, Ciudad Real, 13071, Spain
- Regional Institute for Applied Chemistry Research (IRICA), Ciudad Real, 13071, Spain
| | - M Jesús Villaseñor
- Department of Analytical Chemistry and Food Technology, Faculty of Chemical Science and Technology, University of Castilla-La Mancha, Ciudad Real, 13071, Spain
- Department of Analytical Chemistry, Industrial Engineering School, University of Castilla-La Mancha, Ciudad Real, 13071, Spain
| | - Ángel Ríos
- Department of Analytical Chemistry and Food Technology, Faculty of Chemical Science and Technology, University of Castilla-La Mancha, Ciudad Real, 13071, Spain.
- Regional Institute for Applied Chemistry Research (IRICA), Ciudad Real, 13071, Spain.
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2
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Lu Y, Jin B, Zheng R, Wu S, Zhao D, Qiu M. Production and Patterning of Fluorescent Quantum Dots by Cryogenic Electron-Beam Writing. ACS APPLIED MATERIALS & INTERFACES 2023; 15:12154-12160. [PMID: 36848286 DOI: 10.1021/acsami.2c21052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Graphene quantum dots (GQDs) have emerged as a promising type of functional material with distinguished properties. Although tremendous effort was devoted to the preparation of GQDs, their applications are still limited due to a lack of methods for processing GQDs from synthesis to patterning smoothly. Here, we demonstrate that aromatic molecules, e.g., anisole, can be directly converted into GQD-containing nanostructures by cryogenic electron-beam writing. Such an electron-beam irradiation product exhibits evenly red fluorescence emission under laser excitation at 473 nm, and its photoluminescence intensity can be easily tuned with the electron-beam exposure dose. Experimental characterizations on the chemical composition of the product reveal that anisole undergoes a carbonization and further graphitization process during e-beam irradiation. With conformal coating of anisole, our approach can create arbitrary fluorescent patterns on both planar and curved surfaces for concealing information or anticounterfeiting applications. This study provides a one-step method for production and patterning of GQDs, facilitating their applications in highly integrated and compact optoelectronic devices.
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Affiliation(s)
- Yihan Lu
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, China
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou 310024, China
- Institute of Advanced Technology, Westlake Institute for Advanced Study, Hangzhou 310024, China
| | - Binbin Jin
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou 310024, China
- Institute of Advanced Technology, Westlake Institute for Advanced Study, Hangzhou 310024, China
| | - Rui Zheng
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, China
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou 310024, China
- Institute of Advanced Technology, Westlake Institute for Advanced Study, Hangzhou 310024, China
| | - Shan Wu
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou 310024, China
- Institute of Advanced Technology, Westlake Institute for Advanced Study, Hangzhou 310024, China
| | - Ding Zhao
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou 310024, China
- Institute of Advanced Technology, Westlake Institute for Advanced Study, Hangzhou 310024, China
| | - Min Qiu
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou 310024, China
- Institute of Advanced Technology, Westlake Institute for Advanced Study, Hangzhou 310024, China
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3
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Centane S, Nyokong T. Co phthalocyanine mediated electrochemical detection of the HER2 in the presence of Au and CeO2 nanoparticles and graphene quantum dots. Bioelectrochemistry 2023; 149:108301. [DOI: 10.1016/j.bioelechem.2022.108301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 10/03/2022] [Accepted: 10/08/2022] [Indexed: 11/06/2022]
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4
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Fabrication of nitrogen-doped graphene quantum dots hybrid membranes and its sorption for Cu(II), Co(II) and Pb(II) in mixed polymetallic solution. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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5
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Jokazi M, Mpeta L, nyokong T. Electrocatalytic behavior of manganese and cobalt porphyrins attached to graphene quantum dots: Applied in the oxidation of hydrazine. ELECTROANAL 2022. [DOI: 10.1002/elan.202200222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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6
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Magaela NB, Matshitse R, Babu B, Managa M, Prinsloo E, Nyokong T. Sn(IV) porphyrin-biotin decorated nitrogen doped graphene quantum dots nanohybrids for photodynamic therapy. Polyhedron 2022. [DOI: 10.1016/j.poly.2021.115624] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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7
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Jokazi M, Mpeta LS, Nyokong T. Electrocatalytic activity of manganese tetra 4-aminophenyl porphyrin in the presence of graphene quantum dots. J Electroanal Chem (Lausanne) 2021. [DOI: 10.1016/j.jelechem.2021.115748] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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8
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Nene LC, Nyokong T. Photo-sonodynamic combination activity of cationic morpholino-phthalocyanines conjugated to nitrogen and nitrogen-sulfur doped graphene quantum dots against MCF-7 breast cancer cell line in vitro. Photodiagnosis Photodyn Ther 2021; 36:102573. [PMID: 34628070 DOI: 10.1016/j.pdpdt.2021.102573] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 09/23/2021] [Accepted: 10/04/2021] [Indexed: 01/19/2023]
Abstract
In this work, we explore the reactive oxygen species (ROS) generation abilities of cationic morpholino-substituted-phthalocyanine (Pc) conjugated to nitrogen (NGQDs) and nitrogen-sulfur (NSGQDs) doped-graphene quantum dots upon irradiation with light for photodynamic therapy (PDT), ultrasound for sonodynamic therapy (SDT) and the combination of both in photo-sonodynamic therapy (PSDT). The in vitro cytotoxicity studies were conducted using the Michigan Cancer Foundation-7 breast cancer cell lines (MCF-7 cells). For PDT treatments, only the 1O2 was detected for all the sensitizers, whereas both the 1O2 and •OH radicals were evident after SDT and PSDT treatments. An increase in the 1O2 generation was observed for the conjugates compared to the GQDs and the Pc alone. However, the •OH radicals were reduced in the conjugates compared to the GQDs and the Pc alone. The NGQDs generally showed better ROS generation efficacy compared to the NSGQDs, alone and in the conjugates. The combination therapy also shows improved efficacy compared to the monotherapies for the Pcs and Pc-GQDs conjugates.
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Affiliation(s)
- Lindokuhle Cindy Nene
- Institute of Nanotechnology Innovation, Rhodes University, P.O. 94, Makhanda, South Africa
| | - Tebello Nyokong
- Institute of Nanotechnology Innovation, Rhodes University, P.O. 94, Makhanda, South Africa.
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9
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Nxele SR, Nyokong T. The electrochemical detection of prostate specific antigen on glassy carbon electrode modified with combinations of graphene quantum dots, cobalt phthalocyanine and an aptamer. J Inorg Biochem 2021. [PMID: 33992966 DOI: 10.1016/j.dyepig.2021.109407] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Herein, a novel aptasensor is developed for the electrochemical detection of prostate specific antigen (PSA) on electrode surfaces modified using various combinations of a Cobalt phthalocyanine (CoPc), an aptamer and graphene quantum dots (GQDs). Electrochemical impedance spectroscopy (EIS) as well as differential pulse voltammetry (DPV) are employed for the detection of PSA. In both analytical techniques, linear calibration curves were observed at a concentration range of 1.2-2.0 pM. The glassy carbon electrode where CoPc and GQDs are placed on the electrode when non-covalently linked followed by addition of the aptamer (GQDs-CoPc(ππ)-aptamer (sequential)) showed the best performance with a limit of detection (LoD) as low as 0.66 pM when using DPV. The detection limits were much lower than the dangerous levels reported for PSA in males tested for prostate cancer. This electrode showed selectivity for PSA in the presence of bovine serum albumin, glucose and L-cysteine. The aptasensor showed good stability, reproducibility and repeatability, deeming it a promising early detection device for prostate cancer.
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Affiliation(s)
- Siphesihle Robin Nxele
- Institute for Nanotechnology Innovation, Chemistry Department, Rhodes University, Grahamstown 6140, South Africa
| | - Tebello Nyokong
- Institute for Nanotechnology Innovation, Chemistry Department, Rhodes University, Grahamstown 6140, South Africa.
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10
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Sen P, Nwahara N, Nyokong T. Photodynamic antimicrobial activity of benzimidazole substituted phthalocyanine when conjugated to Nitrogen Doped Graphene Quantum Dots against Staphylococcus aureus. MAIN GROUP CHEMISTRY 2021. [DOI: 10.3233/mgc-210030] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In this study, peripherally benzimidazole unit substituted ZnPc (1) and its conjugation to nitrogen doped graphene quantum dot (NGQD) as potential phthalocyanine support via π-π stacking have been presented and fully characterized. The bottom-up solution-based synthesized NGQDs was conjugated non-covalently to zinc phthalocyanine to form NGQDs-Pc nanoconjugates. The photophysical and photochemical properties of both such as absorption, fluorescence, fluorescence life time, singlet oxygen quantum yields, triplet state quantum yields and exited state lifetimes were investigated in solutions. We observed a decrease in the fluorescence quantum yields with a corresponding increase in the triplet quantum yield and singlet oxygen quantum yield of the nanoconjugates in comparison to the phthalocyanine complex alone. Photodynamic antimicrobial chemotherapy activities (PACT) of ZnPc alone and its nanoconjugate were determined towards Staphylococcus aureus.
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Affiliation(s)
- Pinar Sen
- Institute for Nanotechnology Innovation, Department of Chemistry, Rhodes University, Grahamstown, South Africa
| | - Nnamdi Nwahara
- Institute for Nanotechnology Innovation, Department of Chemistry, Rhodes University, Grahamstown, South Africa
| | - Tebello Nyokong
- Institute for Nanotechnology Innovation, Department of Chemistry, Rhodes University, Grahamstown, South Africa
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11
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Kir Ş, Dehri İ, Önal Y, Esen R. Graphene quantum dots prepared from dried lemon leaves and microcrystalline mosaic structure. LUMINESCENCE 2021; 36:1365-1376. [PMID: 33891362 DOI: 10.1002/bio.4060] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 04/08/2021] [Accepted: 04/17/2021] [Indexed: 01/01/2023]
Abstract
There are the smallest structural units (carbon and/or quantum dots) in the structure of living plants. This carbon and/or quantum dots are stem cells of plants.
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Affiliation(s)
- Şifa Kir
- Faculty of Science & Letters, Department of Chemistry, Çukurova University, Adana, Turkey
| | - İlyas Dehri
- Faculty of Science & Letters, Department of Chemistry, Çukurova University, Adana, Turkey
| | - Yunus Önal
- Faculty of Engineering, Department of Chemical Engineering, Inonu University, Malatya, Turkey
| | - Ramazan Esen
- Faculty of Science & Letters, Department of Physics, Çukurova University, Adana, Turkey
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12
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Ndebele N, Mgidlana S, Nyokong T. Electrocatalytic Activity of Cobalt Phthalocyanines Revisited: Effect of the Number of Oxygen Atoms and Conjugation to Carbon Nanomaterials. Electrocatalysis (N Y) 2021. [DOI: 10.1007/s12678-021-00670-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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13
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Sen P, Nyokong T. Promising photodynamic antimicrobial activity of polyimine substituted zinc phthalocyanine and its polycationic derivative when conjugated to nitrogen, sulfur, co-doped graphene quantum dots against Staphylococcus aureus. Photodiagnosis Photodyn Ther 2021; 34:102300. [PMID: 33894371 DOI: 10.1016/j.pdpdt.2021.102300] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 03/04/2021] [Accepted: 04/16/2021] [Indexed: 01/15/2023]
Abstract
Antimicrobial resistance is a most important problem facing the treatment of infectious diseases. Antimicrobial photodynamic therapy is an alternative treatment strategy, considered to be cost-effective and feasible. For this purpose, octa-imine substituted ZnPc (3) have been prepared and conjugated to nitrogen, sulfur co-doped graphene quantum dots (N,S-GQDs) through π-π stacking. The photophysical and photochemical properties of Pc alone and and Pc-conjugated to the GQD nanomaterial such as absorption, fluorescence, fluorescence life time, singlet oxygen quantum yields, triplet state quantum yields and exited state lifetimes were investigated in solutions before in vitro cell studies. The PACT activity of prepared structures was investigated against Gram-positive (Staphylococcus aureus). Our results suggest that the in the case of conjugation of zinc Pc to N,S-GQDs, photodynamic inactivation increased with the 100 % reduction percentage.
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Affiliation(s)
- Pinar Sen
- Institute for Nanotechnology Innovation, Department of Chemistry, Rhodes University, PO Box 94, Grahamstown, 6140, South Africa.
| | - Tebello Nyokong
- Institute for Nanotechnology Innovation, Department of Chemistry, Rhodes University, PO Box 94, Grahamstown, 6140, South Africa.
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14
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The electrochemical detection of prostate specific antigen on glassy carbon electrode modified with combinations of graphene quantum dots, cobalt phthalocyanine and an aptamer. J Inorg Biochem 2021; 221:111462. [PMID: 33992966 DOI: 10.1016/j.jinorgbio.2021.111462] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 04/07/2021] [Accepted: 04/08/2021] [Indexed: 01/04/2023]
Abstract
Herein, a novel aptasensor is developed for the electrochemical detection of prostate specific antigen (PSA) on electrode surfaces modified using various combinations of a Cobalt phthalocyanine (CoPc), an aptamer and graphene quantum dots (GQDs). Electrochemical impedance spectroscopy (EIS) as well as differential pulse voltammetry (DPV) are employed for the detection of PSA. In both analytical techniques, linear calibration curves were observed at a concentration range of 1.2-2.0 pM. The glassy carbon electrode where CoPc and GQDs are placed on the electrode when non-covalently linked followed by addition of the aptamer (GQDs-CoPc(ππ)-aptamer (sequential)) showed the best performance with a limit of detection (LoD) as low as 0.66 pM when using DPV. The detection limits were much lower than the dangerous levels reported for PSA in males tested for prostate cancer. This electrode showed selectivity for PSA in the presence of bovine serum albumin, glucose and L-cysteine. The aptasensor showed good stability, reproducibility and repeatability, deeming it a promising early detection device for prostate cancer.
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15
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Rani P, Ahamed B, Deshmukh K. Electromagnetic interference shielding properties of graphene
quantum‐dots
reinforced poly(vinyl alcohol)/polypyrrole blend nanocomposites. J Appl Polym Sci 2020. [DOI: 10.1002/app.49392] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Priyanka Rani
- Department of PhysicsB. S. Abdur Rahman Crescent Institute of Science and Technology Chennai India
| | - Basheer Ahamed
- Department of PhysicsB. S. Abdur Rahman Crescent Institute of Science and Technology Chennai India
| | - Kalim Deshmukh
- New Technologies—Research CentreUniversity of West Bohemia Plzeň Czech Republic
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16
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Mallakpour S, Khadem E. Linear and nonlinear behavior of crosslinked chitosan/N-doped graphene quantum dot nanocomposite films in cadmium cation uptake. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 690:1245-1253. [PMID: 31470487 DOI: 10.1016/j.scitotenv.2019.06.431] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 06/20/2019] [Accepted: 06/26/2019] [Indexed: 05/12/2023]
Abstract
In this research, crosslinked nanocomposite (NC) films involving chitosan (CS) and various percentages of nitrogen-doped graphene quantum dot (NGQD) were prepared via ultrasonic acoustic accompanied by adding glutaraldehyde as a crosslinking agent (henceforth nominated as CCS/NGQD NC). The objective of this study is the design of a safe adsorbent of CCS/NGQD NC under easy and low-cost conditions to investigate the mechanisms of Cd(II) ion sorption and find an appropriate model for the kinetics of removal. By comparing adsorption ability of CCS/NGQD NC films 2, 5 and 8 wt% under the same conditions, the CCS NC film with 5 wt% of NGQD was selected as the best mass ratio to investigate the adsorption process. To understand the nature of the sorption behavior, the experimental data were used to calculate pseudo-first-order, pseudo-second-order, and intra-particle diffusion kinetic models, and various isotherm models in linear and nonlinear regression. In addition, some error functions were applied to detect, either linear or nonlinear model is suitable to examine the experimental data and prevent any huge mistakes. The linear Freundlich equation well describes the uptake of Cd(II) ion by CCS film and CCS/NGQD NC film 5 wt%. Based on linear Langmuir, the maximum adsorption capacities of CCS film and CCS/NGQD NC film 5 wt% were 34.46 and 35.00 mg·g-1, respectively. Kinetic analysis indicates that the mechanism of removal is described by nonlinear pseudo-second order model for CCS film and linear pseudo-second order model for the CCS/NGQD NC film 5 wt%. Also, thermodynamic parameters were analyzed in different temperatures. The obtained thermodynamic values prove that Cd(II) ion adsorption on both adsorbents is feasible, spontaneous and endothermic.
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Affiliation(s)
- Shadpour Mallakpour
- Organic Polymer Chemistry Research Laboratory, Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111, Islamic Republic of Iran; Research Institute for Nanotechnology and Advanced Materials, Isfahan University of Technology, Isfahan 84156-83111, Islamic Republic of Iran.
| | - Elham Khadem
- Organic Polymer Chemistry Research Laboratory, Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111, Islamic Republic of Iran
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17
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Mallakpour S, Khadem E. Construction of crosslinked chitosan/nitrogen-doped graphene quantum dot nanocomposite for hydroxyapatite biomimetic mineralization. Int J Biol Macromol 2018; 120:1451-1460. [DOI: 10.1016/j.ijbiomac.2018.09.127] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 09/09/2018] [Accepted: 09/20/2018] [Indexed: 02/07/2023]
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18
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Xu X, Gao F, Bai X, Liu F, Kong W, Li M. Tuning the Photoluminescence of Graphene Quantum Dots by Photochemical Doping with Nitrogen. MATERIALS (BASEL, SWITZERLAND) 2017; 10:E1328. [PMID: 29156648 PMCID: PMC5706275 DOI: 10.3390/ma10111328] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 10/31/2017] [Accepted: 11/14/2017] [Indexed: 01/15/2023]
Abstract
Nitrogen-doped graphene quantum dots (NGQDs) were synthesized by irradiating graphene quantum dots (GQDs) in an NH₃ atmosphere. The photoluminescence (PL) properties of the GQDs and the NGQDs samples were investigated. Compared with GQDs, a clear PL blue-shift of NGQDs could be achieved by regulating the irradiating time. The NGQDs obtained by irradiation of GQDs for 70 min had a high N content of 15.34 at % and a PL blue-shift of about 47 nm. This may be due to the fact that photochemical doping of GQDs with nitrogen can significantly enhance the contents of pyridine-like nitrogen, and also effectively decrease the contents of oxygen functional groups of NGQDs, thus leading to the observed obvious PL blue-shift.
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Affiliation(s)
- Xiaofen Xu
- College of Physics and Technology, Guangxi Normal University, Guilin 541004, China.
| | - Fuhua Gao
- College of Physics and Technology, Guangxi Normal University, Guilin 541004, China.
| | - Xiaohua Bai
- College of Physics and Technology, Guangxi Normal University, Guilin 541004, China.
| | - Fuchi Liu
- College of Physics and Technology, Guangxi Normal University, Guilin 541004, China.
| | - Wenjie Kong
- College of Physics and Technology, Guangxi Normal University, Guilin 541004, China.
| | - Ming Li
- College of Science, Guilin University of Technology, Guilin 541004, China.
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19
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Centane S, Achadu OJ, Nyokong T. Effects of Substituents on the Electrocatalytic Activity of Cobalt Phthalocyanines when Conjugated to Graphene Quantum Dots. ELECTROANAL 2017. [DOI: 10.1002/elan.201700252] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Sixolile Centane
- Chemistry Department; Rhodes University; Grahamstown 6140 South Africa, Tel:+27 46 6038260 Fax:+27 46 6225109
| | - Ojodomo J. Achadu
- Chemistry Department; Rhodes University; Grahamstown 6140 South Africa, Tel:+27 46 6038260 Fax:+27 46 6225109
| | - Tebello Nyokong
- Chemistry Department; Rhodes University; Grahamstown 6140 South Africa, Tel:+27 46 6038260 Fax:+27 46 6225109
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20
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Bankole OM, Achadu OJ, Nyokong T. Nonlinear Interactions of Zinc Phthalocyanine-Graphene Quantum Dots Nanocomposites: Investigation of Effects of Surface Functionalization with Heteroatoms. J Fluoresc 2017; 27:755-766. [DOI: 10.1007/s10895-016-2008-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 12/20/2016] [Indexed: 11/29/2022]
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21
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Li N, Than A, Sun C, Tian J, Chen J, Pu K, Dong X, Chen P. Monitoring Dynamic Cellular Redox Homeostasis Using Fluorescence-Switchable Graphene Quantum Dots. ACS NANO 2016; 10:11475-11482. [PMID: 28024361 DOI: 10.1021/acsnano.6b07237] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Monitoring cellular redox homeostasis is critical to the understanding of many physiological functions ranging from immune reactions to metabolism, as well as to the understanding of pathological development ranging from tumorigenesis to aging. Nevertheless, there is currently a lack of appropriate probes for this ambition, which should be reversibly, sensitively, and promptly responsive to a wide range of physiological oxidants and reductants. In this work, a redox-sensitive fluorescence-switchable probe is designed based on graphene quantum dots (GQDs) functionalized with a chelated redox Fe2+/Fe3+ couple. The underlying mechanism is investigated and discussed. The high sensitivity and fast response are attributable to the fact that the GQD's photoluminescence is highly sensitive to photon-induced electron transfer because of its ultrasmall size and associated prominent quantum confinement effect. Also taking advantages of GQDs' excellent photostability, biocompatibility, and readiness for cell uptake, our reversibly tunable fluorescence probe is employed to monitor in real time the triggered dynamic change of the intracellular redox state. This addition to the limited arsenal of available redox probes shall be useful to the still poorly understood redox biology, as well as for monitoring environment or chemical processes involving redox reactions.
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Affiliation(s)
- Nan Li
- Division of Bioengineering, School of Chemical & Biomedical Engineering, Nanyang Technological University , 70 Nanyang Drive, Singapore 637457
| | - Aung Than
- Division of Bioengineering, School of Chemical & Biomedical Engineering, Nanyang Technological University , 70 Nanyang Drive, Singapore 637457
| | - Chencheng Sun
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (NanjingTech) , 30 South Puzhu Road, Nanjing 211816, China
| | - Jingqi Tian
- Division of Bioengineering, School of Chemical & Biomedical Engineering, Nanyang Technological University , 70 Nanyang Drive, Singapore 637457
| | - Jie Chen
- Division of Bioengineering, School of Chemical & Biomedical Engineering, Nanyang Technological University , 70 Nanyang Drive, Singapore 637457
| | - Kanyi Pu
- Division of Bioengineering, School of Chemical & Biomedical Engineering, Nanyang Technological University , 70 Nanyang Drive, Singapore 637457
| | - Xiaochen Dong
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (NanjingTech) , 30 South Puzhu Road, Nanjing 211816, China
| | - Peng Chen
- Division of Bioengineering, School of Chemical & Biomedical Engineering, Nanyang Technological University , 70 Nanyang Drive, Singapore 637457
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Achadu OJ, Britton J, Nyokong T. Graphene Quantum Dots Functionalized with 4-Amino-2, 2, 6, 6-Tetramethylpiperidine-N-Oxide as Fluorescence “Turn-ON” Nanosensors. J Fluoresc 2016; 26:2199-2212. [DOI: 10.1007/s10895-016-1916-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 08/26/2016] [Indexed: 11/29/2022]
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Achadu OJ, Uddin I, Nyokong T. The interaction between graphene quantum dots grafted with polyethyleneimine and Au@Ag nanoparticles: Application as a fluorescence “turn-on” nanoprobe. J Photochem Photobiol A Chem 2016. [DOI: 10.1016/j.jphotochem.2016.03.016] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Achadu OJ, Nyokong T. Application of graphene quantum dots decorated with TEMPO-derivatized zinc phthalocyanine as novel nanoprobes: probing the sensitive detection of ascorbic acid. NEW J CHEM 2016. [DOI: 10.1039/c6nj01796g] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A nanocomposite of (2,2,6,6-tetramethylpiperidin-1-yl)oxyl substituted zinc phthalocyanine and graphene quantum dots is a selective fluorescence sensor for ascorbic acid.
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