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A novel fluorescent probe for H2O2 detection based on CdSe@ZnS quantum dots/Ag nanocluster hybrid
摘要： The selective and quantitative detection of H2O2 is important for its employment in physiological, environmental and industrial applications. In this paper, a sensitive and selective strategy for H2O2 detection was established based on the fluorescence quenching of CdSe@ZnS quantum dots (QDs) by H2O2-mediated etching process of Ag nanoclusters (AgNCs). In this strategy, dihydrolipoic acid (DHLA) modified AgNCs were applied as H2O2 response group, the existence of H2O2 could initiate the oxidation of AgNCs and the production of Ag+, which could give rise to the effective fluorescence quenching of CdSe@ZnS QDs. Based on this strategy, the present fluorescent assay could realize the quantificational detection of H2O2 and the limit of detection is calculated to be 0.3 mM under the optimum conditions. Furthermore, CdSe@ZnS/AgNCs hybrid-based probe was applied to detecting H2O2 in milk samples and showed a good recoveries results ranged from 95.8% to 112.0%, meaning the potential applicability of this strategy.
关键词： H2O2 detection,Ag nanoclusters,Fluorescence quenching,CdSe@ZnS quantum dots
更新于2025-11-19 16:46:39
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One-step Aqueous Synthesis of Zn-based Quantum Dots as Potential Generators of Reactive Oxygen Species
摘要： The actual incorporation of dopant species into the ZnS Quantum Dots (QDs) host lattice will induce structural defects evidenced by a red shift in the corresponding exciton. The doping should create new intermediate energetic levels between the valence and conduction bands of the ZnS and affect the electron-hole recombination. These trap states would favour the energy transfer processes involved with the generation of cytotoxic radicals, so-called Reactive Oxygen Species, opening the possibility to apply these nanomaterials in cancer research. Any synthesis approach should consider the direct formation of the QDs in biocompatible medium. Accordingly, the present work addresses the microwave-assisted aqueous synthesis of pure and doped ZnS QDs. As-synthesized quantum dots were fully characterized on a structural, morphological and optical viewpoint. UV-Vis analyzes evidenced the excitonic peaks at approximately 310 nm, 314 nm and 315 nm for ZnS, Cu-ZnS and Mn-ZnS, respectively, Cu/Zn and Mn/Zn molar ratio was 0.05%. This indicates the actual incorporation of the dopant species into the host lattice. In addition, the Photoluminescence spectrum of non-doped ZnS nanoparticles showed a high emission peak that was red shifted when Mn2+ or Cu2+ were added during the synthesis process. The main emission peak of non-doped ZnS, Cu-doped ZnS and Mn-doped ZnS were observed at 438 nm, 487 nm and 521 nm, respectively. Forthcoming work will address the capacity of pure and Cu-, Mn-ZnS quantum dots to generate cytotoxic Reactive Oxygen Species for cancer treatment applications.
关键词： Cancer research,ZnS Quantum Dots,Doping,Microwave-assisted synthesis,Reactive Oxygen Species
更新于2025-11-19 16:46:39
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Mn-Doped ZnS Quantum dotsa?? An EffectiveNanoscale Sensor
摘要： Quantum dots (QDs), due inter alia to their colourtunable symmetry, narrow emission, broad absorption, stability, and solution processibility have received an upsurge of interest in the last decade as potential materials for diverse applications. Doped QDs, in particular, have gained significant attention as a new class of luminescent materials since dopants influence the optical behaviour of QDs. Therefore, doped ZnS QDs possess conspicuous properties like longer dopant emission lifetime and lower toxicity. The dopant emission lifetimes of transition-metal ions are longer than the energy-gap and defect-related luminescence of the host as well as the biological background fluorescence to offer immense prospect for removal of background fluorescence for sensing applications. Probes based on phosphorescence or fluorescence enhancement of QDs is crucial for the development of the detection capability. This current review highlights the optical property and various sensing strategies of Mn-doped ZnS QDs that make them exceptional probes for applications in sensing. The review not only intends to present an all-encompassing study of the well-documented usages of QDs, but is also rather addressing the current promising improvements, concepts, and excellent applications in research of doped QDs for chemo- and biosensing. Over 200 publications are overviewed and considered here in the perspective of leading applications in sensing dealing with for instance, fluorescence, phosphorescence, chemiluminescence, electrochemiluminescence and biosensing features.
关键词： Quantum dots,chemosensing,Mn-doped ZnS quantum dots,biosensing
更新于2025-09-23 15:19:57
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Inorganic Functionalization of CdSe <sub/><i>x</i> </sub> S <sub/> 1a?? <i>x</i> </sub> /ZnS Corea??Shell Quantum Dots and Their Photoelectric Properties
摘要： In this paper, different CdSexS1-x quantum dots (QDs) with stearic acid as ligands were synthesized, and then the outer ZnS shell was coated with oleylamine (OLA) as ligands using a single molecular source method. The surface ligand exchange of CdSe0.6S0.4 and CdSe0.6S0.4/ZnS quantum dots was carried out with ammonium zinc chloride ((NH4)2ZnCl4) inorganic ligands. The morphology, crystal form, and group of QDs were examined using a high-resolution transmission electron microscope (HRTEM), X-ray diffraction (XRD) and fourier transform infrared spectroscopy (FTIR). Under the condition of simulated sunlight irradiation, the photoelectrochemical properties were tested with an electrochemical workstation. The results showed that the distance between QDs decreased after ligand exchange. The photocurrent density of CdSe0.6S0.4/ZnS QDs films after ligand exchange can reach 7.23 mA?cm-2, which is 11 times that of the photocurrent density before ligand exchange. The reason may be that ZnCl42- has strong ligand electron donor capacity, which increases the probability of non-radiative transition.
关键词： Inorganic functionalization,(NH4)2ZnCl4,CdSexS1-x/ZnS quantum dots
更新于2025-09-23 15:19:57
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Development of a ZnCdS@ZnS quantum dotsa??based label-free electrochemiluminescence immunosensor for sensitive determination of aflatoxin B1 in lotus seed
摘要： In this study, we designed a ZnCdS@ZnS quantum dots (QDs)–based label-free electrochemiluminescence (ECL) immunosensor for sensitive determination of aflatoxin B1 (AFB1). A Nafion solution assembled abundant QDs on the surface of a Au electrode as ECL signal probes, with specially coupled anti-AFB1 antibodies as the capturing element. As the reduction reaction between S2O8 2? in the electrolyte and QDs on the electrode led to ECL emission, the decreased ECL signals resulting from target AFB1 in the samples were recorded for quantification. We evaluated electrochemical impedance spectroscopy and ECL measurements along each step in the construction of the proposed immunosensor. After systematic optimization of crucial parameters, the ECL immunosensor exhibited a good sensitivity, with a low detection limit of 0.01 ng/mL for AFB1 in a wide concentration range of 0.05–100 ng/mL. Testing with lotus seed samples confirmed the satisfactory selectivity, stability, and reproducibility of the developed ECL immunosensor for rapid, efficient, and sensitive detection of AFB1 at trace levels in complex matrices. This study provides a powerful and universal analytical platform for a variety of analytes that can be used in broad applications for real-time analysis, such as food and traditional Chinese medicine safety testing, environmental pollution monitoring, and disease diagnostics.
关键词： Electrochemiluminescence immunosensor,Nafion,Lotus seed,Aflatoxin B1,ZnCdS@ZnS quantum dots,Label-free
更新于2025-09-23 15:19:57
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Microwave activated synthesis of Ag2S and Ag2S@ZnS nanocrystals and their application in well-performing quantum dot sensitized solar cells
摘要： Incident photon-to-current conversion e?ciency (IPCE) of CdS based quantum dot sensitized solar cells (QDSCs) is a major drawback in their low e?ciency. Here we report a new trend in fabrication of QDSC with enhanced IPCE with application of as prepared Ag2S and Ag2S@ZnS QDs as a co sensitizer. Ag2S and Ag2S@ZnS QDs were synthesized ?rst using a microwave method and were examined by means of XRD, TEM and UV–Vis spectroscopy. Then the prepared QDs were applied for the fabrication of QDSCs using a novel drop casting method. The results revealed a signi?cant enhancement of IPCE as well as short current density (12.5 mA·cm?2) and cell e?ciency (3%). The enhancement is directly related to well absorption of Ag2S with low band gap in the visible range and e?ective injection of photo-excited electrons to CdS compact layer according to suggested band diagram. Ag2S@ZnS co-sensitizer showed an enhancement in photocurrent density due to successful passivation of Ag2S QDs and suppressing recombination on their surface.
关键词： Ag2S@ZnS quantum dots,QD sensitized solar cells,IPCE,Drop casting
更新于2025-09-23 15:19:57
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<p>In vivo Comparison of the Biodistribution and Toxicity of InP/ZnS Quantum Dots with Different Surface Modifications</p>
摘要： In vivo Comparison of the Biodistribution and Toxicity of InP/ZnS Quantum Dots with Different Surface Modifications
关键词： in vivo,surface chemistry,nanotoxicology,biodistribution,InP/ZnS quantum dots
更新于2025-09-23 15:19:57
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Photophysical Properties of Multilayer Graphenea??Quantum Dots Hybrid Structures
摘要： Photoelectrical and photoluminescent properties of multilayer graphene (MLG)–quantum dots (QD) hybrid structures have been studied. It has been shown that the average rate of transfer from QDs to the MLG can be estimated via photoinduced processes on the QDs’ surfaces. A monolayer of CdSe QDs can double the photoresponse amplitude of multilayer graphene, without influencing its characteristic photoresponse time. It has been found that efficient charge or energy transfer from QDs to MLG with a rate higher than 3 × 108 s?1 strongly inhibits photoinduced processes on the QD surfaces and provides photostability for QD-based structures.
关键词： photophysical properties,CdSe–ZnS quantum dots,hybrid structures,photoelectrical properties,multilayered graphene,photoactivation
更新于2025-09-23 15:19:57
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Alleviating the toxicity of quantum dots to Phanerochaete chrysosporium by sodium hydrosulfide and cysteine
摘要： Quantum dots (QDs) have caused large challenges in clinical tests and biomedical applications due to their potential toxicity from nanosize effects and heavy metal components. In this study, the physiological responses of Phanerochaete chrysosporium (P. chrysosporium) to CdSe/ZnS QDs with either an inorganic sulfide NaHS or an organic sulfide cysteine as antidote have been investigated. Scanning electron microscope analysis showed that the hyphal structure and morphology of P. chrysosporium have obviously changed after exposure to 100 nM of COOH CdSe/ZnS 505, NH2 CdSe/ZnS 505, NH2 CdSe/ZnS 565, or NH2 CdSe/ZnS 625. Fourier transform infrared spectroscopy analysis indicated that the existence of hydroxyl, amino, and carboxyl groups on cell surface could possibly conduct the stabilization of QDs in an aqueous medium. However, after NaHS or cysteine treatment, the cell viability of P. chrysosporium exposed to CdSe/ZnS QDs increased as compared to control group, since NaHS and cysteine have assisted P. chrysosporium to alleviate oxidative damage by regulating lipid peroxidation and superoxide production. Meanwhile, NaHS and cysteine have also stimulated P. chrysosporium to produce more antioxidant enzymes (superoxide dismutase and catalase), which played significant roles in the defense system. In addition, NaHS and cysteine were used by P. chrysosporium as sulfide sources to promote the glutathione biosynthesis to relieve CdSe/ZnS QDs-induced oxidative stress. This work revealed that sulfide sources (NaHS and cysteine) exerted a strong positive effect in P. chrysosporium against the toxicity induced by CdSe/ZnS QDs.
关键词： Detoxification,Cysteine,CdSe/ZnS quantum dots,Sodium hydrosulfide,Antioxidant enzymes,Oxidative stress
更新于2025-09-23 15:19:57
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Selective and sensitive determination of celastrol in traditional Chinese medicine based on molecularly imprinted polymers modified Mn-doped ZnS quantum dots optosensing materials
摘要： In this work, we proposed a facile strategy to prepare molecularly imprinted polymers (MIPs) modified Mn-doped ZnS quantum dots (QDs) as optosensing materials via sol-gel polymerization for specific recognition of celastrol (Cel) in traditional Chinese medicine (TCM). Firstly, L-Cysteine (L-Cys) modified Mn-doped ZnS QDs (L-Cys@Mn-ZnS) was used as imprinting substrate. The amino and carboxyl groups on the surface of Mn-ZnS QDs can provide more binding sites for imprinting polymerization. Then, the fluorescent MIPs was synthesized in the presence of L-Cys@Mn-ZnS QDs, template celastrol, 3-aminopropyl triethoxysilane (APTES) and ammonium hydroxide in the ethanol-water (9/1, v/v) solution. The morphology and structure of the products were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometer (XRD) and X-ray photoelectron spectroscopy (XPS). The resulting MIPs functionalized Mn-doped ZnS QDs (denoted as MIPs@L-Cys@Mn-ZnS QDs) had higher imprinting factor of 14.19 and significant selectivity. The MIPs@L-Cys@Mn-ZnS QDs as fluorescent probe exhibited sensitive response to Cel in the linear range from 0.1 μM to 3.5 μM and the limit of detection was estimated to be 35.2 nM. The probe was also applied for the detection of Cel in traditional Chinese medicine with recovery ranged from 88.0% to 105.0%. The results confirmed that MIPs@L-Cys@Mn-ZnS QDs could efficiently and specifically capture Cel from actual complex traditional Chinese medicine samples.
关键词： Celastol,Mn-doped ZnS quantum dots,fluorescent probe,traditional Chinese medicine,molecularly imprinted polymers
更新于2025-09-19 17:13:59