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Tuning the luminescence of nitrogen-doped graphene quantum dots synthesized by pulsed laser ablation in liquid and their use as a selective photoluminescence on–off–on probe for ascorbic acid detection
摘要： In this work, nitrogen-doped graphene quantum dots (N-GQDs) were synthesized by pulsed laser ablation in liquid using Nd:YAG laser (532 nm). Graphite target was ablated in dimethylformamide, as solvent and nitrogen source, and the microstructure as well as optical properties of N-GQDs were studied. The N-GQDs structure consists of a graphitic core with oxygen and nitrogen functionalities and particle size about 3 nm, as demonstrated by X-ray photoelectron spectroscopy, Raman spectroscopy and transmission electron microscopy. The as-prepared N-GQDs structure was modified by solvothermal treatment at 65, 90 and 120 °C reducing the oxygen functional groups, adding nitrogen and restoring the π-conjugated structure of N-GQD. The N-GQDs exhibit UV-Vis absorption spectrum with the characteristic π-π* and n – π* electronic transitions of the GQDs with a large amount of oxygen and nitrogen functionalities. These N-GQDs exhibited a visible light photoluminescence centered at 486 nm upon an excitation of 410 nm and the photoluminescence intensity enhanced up to 4.05% of quantum yield after solvothermal treatment. The N-GQDs dispersion was used for selective detection of ascorbic acid, through a signal-off and signal-on system. The results show the use of N-GQDs as a competent photoluminescence sensor for metal ions and ascorbic acid.
关键词： Fluorescence quenching,electron transfer,carbon nanoparticles
更新于2025-11-19 16:56:42
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On-demand CO release for amplification of chemotherapy by MOF functionalized magnetic carbon nanoparticles with NIR irradiation
摘要： Carbon monoxide (CO) gas therapy combined with chemotherapy and photothermal therapy (PTT) is a promising treatment mode for malignant tumor. Herein, we firstly reported doxorubicin (DOX) loaded Mn carbonyl modified Fe (III)-based nanoMOFs (MIL-100) coated PEGylated magnetic carbon nanoparticles (denoted as MCM@PEG-CO-DOX NPs) as theranostics nanoplatforms for near-infrared (NIR)-responded CO-DOX combination therapy. MIL-100 as a good nanocarrier of DOX with high loading capacity can also chelate the Mn carbonyl after a smart modification. Meanwhile, magnetic carbon core possessed photothermal effect, which can convert the NIR light to heat by an 808 nm laser irradiation, resulting in the on-demand release of CO and DOX. As a result, combining with PTT, MCM@PEG-CO-DOX NPs killed tumor efficiently. Moreover, our synthesized MCM@PEG-CO-DOX NPs were capable of realizing tumor dual-mode imaging including magnetic resonance imaging (MRI) and photoacoustic imaging (PAI).
关键词： synergistic treatment,dual-mode imaging,MOFs,CO gas therapy,carbon nanoparticles
更新于2025-09-23 15:23:52
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Aloe-Emodin/Carbon Nanoparticles Hybrid Gels with Light-Induced and Long-Term Antibacterial Activity
摘要： Development of effective antimicrobial wound dressings has drawn wide attention in the wound care market. Here, we synthesized a natural antibiotic (aloe-emodin, AE) and carbon nanoparticles co-embedded polymer hybrid hydrogel as a novel wound dressing in the fight against skin infections potently. We systematically evaluated the properties of the obtained hydrogels, including physic-chemical characteristics, photothermal conversion efficiency, reactive oxygen species (ROS) generation, AE-released profile, antibacterial activity and wound-healing capability. The hybrid gels can initially deduct the number of bacteria rapidly in a short time through the near-infrared-light (NIR)-triggered photothermal/ROS route, and continuously kill the remaining live cells by released-AE from gels after turning off NIR source with the long-term antibacterial effect. These two antibacterial manners that complement each other lead to the excellent antibacterial performances towards various bacterial strains including multidrug-resistant bacteria. Moreover, in vivo Staphylcoccus aureus-infected animal experiments indicate that the hybrid gels upon NIR irradiation have a striking ability towards wound infection. These studies demonstrate that the AE and carbon nanoparticles co-embedded hybrid polymer hydrogels with NIR exposure may have applications in the wound combined care for bacterial infections.
关键词： NIR irradiation,aloe-emodin,wound dressing,ROS,carbon nanoparticles,antibacterial hydrogel
更新于2025-09-23 15:21:21
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Triple stimuli-responsive ZnO quantum dots-conjugated hollow mesoporous carbon nanoplatform for NIR-induced dual model antitumor therapy
摘要： Aiming at the inef?ciency and toxicity in traditional antitumor therapy, a novel multifunctional nanoplat-form was constructed based on hollow mesoporous carbon (HMC) to achieve triple stimuli response and dual model antitumor therapy via chemo-photothermal synergistic effect. HMC was used as an ideal nanovehicle with a high drug loading ef?ciency as well as a near-infrared (NIR) photothermal conversion agent for photothermal therapy. Acid-dissoluble, luminescent ZnO quantum dots (QDs) were used as the proper sealing agents for the mesopores of HMC, conjugated to HMC via disul?de linkage to prevent drug (doxorubicin, abbreviated as Dox) premature release from Dox/HMC-SS-ZnO. After cellular endocytosis, the Dox was released in a pH, GSH and NIR laser triple stimuli-responsive manner to realize accurate drug delivery. Moreover, the local hyperthermia effect induced by NIR irradiation could promote the drug release, enhance cell sensitivity to chemotherapeutic agents, and also directly kill cancer cells. As expected, Dox/HMC-SS-ZnO exhibited a high drug loading capacity of 43%, well response to triple stimuli and excellent photothermal conversion ef?ciency g of 29.7%. The therapeutic ef?cacy in 4T1 cells and multicellular tumor spheroids (MCTSs) demonstrated that Dox/HMC-SS-ZnO + NIR had satisfactory chemo-photothermal synergistic effect with a combination index (CI) of 0.532. The cell apoptosis rate of the combined treatment group was more than 95%. The biodistribution and pharmacodynamics studies showed its biosecurity to normal tissues and synergistic inhibition effect to tumor cells. These distinguished results indicated that the Dox/HMC-SS-ZnO nanoplatform is potential to realize ef?cient triple stimuli-responsive drug delivery and dual model chemo-photothermal synergistic antitumor therapy.
关键词： Chemo-photothermal synergistic therapy,Triple stimuli-responsive,Hollow mesoporous carbon nanoparticles,TEM-EDX mapping,ZnO quantum dots
更新于2025-09-19 17:13:59
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Preparation and characterization of graphene sheet prepared by laser ablation in liquid
摘要： Graphene sheets prepared successfully by Nd: YAG laser ablation of carbon target immersed in deionized water. The structural, optical and morphological properties investigated using Fourier transform infrared spectroscopy, X-ray diffraction, UV–VIS spectrophotometry, photoluminescence spectroscopy, and Transmission electron microscopy. The result of FTIR spectra conform C?C and C@C bonds, which yield to carbon nanoparticles (CNPs) suspend in liquid. After re-irradiation, new peaks appear at 1723 cm(cid:1)1 and 2697 cm(cid:1)1 caused by the disordered arrangement and irregular layer thickness of graphene sheets. The XRD pattern observed sharp peaks at 2h (cid:3) 24(cid:1), 26.6(cid:1), and 43(cid:1) with higher intensity after the re-irradiation process. The absorption result shows a shoulders peaks among 260 and 320 nm relates to transition in C@O and C@C bands. The PL spectra have a peak in the visible region at 597 nm and increased as laser energy increased. TEM images show straight isolated long multiwall carbon nanotubes MWCNT with the hollow core in different dimensions. While graphene sheet it takes the shape of a ?at transparent layer with small wrinkles and folding sheet, appeared after re-irradiation the suspensions with same laser energy.
关键词： Carbon nanoparticles,Carbon nanotubes,Laser ablation,Graphene sheet
更新于2025-09-11 14:15:04
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Producing graphene nanosheets by pulsed laser ablation: Effects of liquid environment
摘要： Effects of liquid environment on the characteristics of graphene nanosheets produced by the laser ablation method have been studied experimentally. The fundamental wavelength of a pulsed Nd:YAG laser at 1064 nm with 7 ns pulse width and 5 Hz repetition rate was employed to irradiate a graphite target in distilled water, liquid nitrogen, alcohol, acetone, and two concentrations of cetyltrimethylammonium bromide. Produced carbon nanostructures were diagnosed using Ultraviolet-Visible-Near Infrared and Fourier transform infrared spectroscopy, x-ray diffraction, Raman spectroscopy, transmission electron microscopy, and field emission scanning electron microscope images. Results show that different carbon nanostructures such as carbon nanoparticles and fluorine, as well as graphene nanosheets were formed in various liquid environments. The size and morphology of nanostructures strongly depends on the liquid environments and, among these liquids, water is the most capable one to produce graphene nanosheets.
关键词： Raman,carbon nanoparticles,graphene nanosheets,graphite,pulsed laser ablation
更新于2025-09-11 14:15:04
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Excitation-independent hollow orange-fluorescent carbon nanoparticles for pH sensing in aqueous solution and living cells
摘要： We report an ingenious strategy for fabrication of hollow orange fluorescent carbon nanoparticles (HFCNs) and demonstrate their applications for pH biosensing and fingerprint detection. HFCNs have been synthesized using 5-amino salicylic acid as carbon source via one-step hydrothermal treatment without further surface passivation or modification. The as-prepared HFCNs possess excellent hollow structure and bright orange fluorescence. The HFCNs display a remarkable emission enhancement in the orange fluorescence region when the pH is increased from 3.0 to 10.0. The pKa value of HFCNs is found to be 5.97 and a good linearity is shown in the pH range of 5.25–6.75, which makes HFCNs an effective intracellular pH imaging agent for acidic microenvironments. The confocal fluorescent microscopic images of HFCNs-stained latent fingerprint are achieved successfully, suggesting that they have great promise for practical criminal investigations as a simple, fast, and accurate tool.
关键词： Orange fluorescence,Hollow,pH sensing,Carbon nanoparticles
更新于2025-09-04 15:30:14