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Determination of BCM-7 based on an ultrasensitive aptasensor fabricated of gold nanoparticles and ZnS quantum dots
摘要： In this study, an ultrasensitive electrochemical aptasensor for the determination of the β-casomorphin 7 (BCM-7) as a promising biomarker of autism disorder is introduced. According to the proposed strategy, a glassy carbon electrode (GCE) was modi?ed by thiourea capped-ZnS QDs (ZnS-QDs) and gold nanoparticles (AuNPs) to further immobilization the amino-aptamer (NH2-Apt) on its surface. The NH2-Apt as a receptor of the BCM-7 was attached to the embedded surface via a formation of the Au–N bonds between the AuNPs and amino groups of the Apt. The evaluation of aptasensor by various electrochemical techniques exhibited successful sensing of the BCM-7 under two broad linear concentration ranges from 1 fM to 0.6 μM with a limit of detection (LOD) down to 350 aM. Also, the performance of the aptasensor in BCM-7 detection in real human urine samples was satisfactorily investigated. These ?ndings may facilitate distinguish of this challenging disorder and help human health.
关键词： Thiourea capped-ZnS QDs,β-casomorphin 7,Glassy carbon electrode,Gold nanoparticles,Aptasensor,Autism
更新于2025-09-23 15:21:01
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Hybrid fluorescent liquid crystalline composites: directed assembly of quantum dots in liquid crystalline block copolymer matrices
摘要： Hybrid ?uorescent liquid crystalline (LC) composites containing inorganic quantum dots (QDs) are promising materials for many applications in optics, nanophotonics and display technology, combining the superior emission capability of QDs with the externally controllable optical properties of LCs. In this work, we propose the hybrid LC composites that were obtained by embedding CdSe/ZnS QDs into a series of host LC block copolymers of di?erent architectures by means of a two-stage ligand exchange procedure. The ABA/BAB triblock copolymers and AB diblock copolymers with di?erent polymerization degrees are composed of nematogenic phenyl benzoate acrylic monomer units and poly(4-vinylpyridine) blocks, which are capable of binding to the QD surface. Our results clearly show that the spatial distribution of QDs within composite ?lms as well as the formation of QD aggregates can be programed by varying the structure of the host block copolymer. The obtained composites form a nematic LC phase, with isotropization temperatures being close to those of the initial host block copolymers. In addition, the in?uence of the molecular architecture of the host block copolymers on ?uorescence properties of the obtained composites is considered. The described strategy for the QD assembly should provide a robust and conventional route for the design of highly ordered hierarchical hybrid materials for many practical applications.
关键词： liquid crystalline block copolymer matrices,ligand exchange procedure,fluorescence properties,CdSe/ZnS QDs,nematic LC phase,Hybrid ?uorescent liquid crystalline composites,quantum dots
更新于2025-09-23 15:19:57
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Synthesis of Water Soluble CuGaS2/ZnS Quantum Dots for Ultrasensitive Fluorescent Detection of Alkaline Phosphatase Based on Inner Filter Effect
摘要： Developing monitoring technique for alkaline phosphatase (ALP) is crucial due to the important role it plays in living cells. Here, a kind of biocompatible glutathione-modified CuGaS2/ZnS quantum dots (GSH-CGS/ZnS QDs) was used as a fluorescent substance and then fabricated “turn-off” fluorescent biosensor for detection of ALP by help of inner filter effect (IFE). Firstly, we prepared CuGaS2/ZnS (CGS/ZnS) QDs using solvothermal method and explored the efficient ligand (GSH) exchanges strategy for transferring oil-soluble CGS/ZnS QDs to aqueous phase. More importantly, we also explored the potential biological applications of the nanohybrid QDs. The obtained GSH-CGS/ZnS QDs emitted strong yellow fluorescence with the maximum excitation (400 nm) and emission (601 nm). Then, GSH-CGS/ZnS QDs were mixed with p-nitrophenylphosphate (PNPP) and ALP. PNPP could be hydrolyzed to p-nitrophenol (PNP) by help of catalysis of ALP, and the excitation spectrum of the GSH-CGS/ZnS QDs overlapped well with the absorption spectrum of PNP, so the fluorescence of GSH-CGS/ZnS QDs was initially quenched via the so-called “IFE”. Finally, a novel “turn-off” biosensor for sensitive detection of ALP in the range of 0.05-10 U L -1(R2 = 0.98) with a detection limit of 0.01 U L-1 was successfully obtained. Results indicated that I-III-VI2 nanocrystals have great potential for their promising biomedical application.
关键词： Inner filter effect,Alkaline phosphatase,GSH-CuGaS2/ZnS QDs,Fluorescent detection,Water solubility and biocompatibility
更新于2025-09-23 15:19:57
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Efficient Perovskite Solar Cells Based on CdSe/ZnS Quantum Dots Electron Transporting Layer with Superior UV Stability
摘要： Stability is the main challenge in the field of perovskite solar cells (PSCs). Finding new strategies is required to protect the PSCs from deteriorated agents such as humidity, heating, and illumination. In this study, we propose a new electron transporting layer (ETL), i.e., CdSe/ZnS quantum dots (QDs) for the fabrication of efficient and stable PSCs. CdSe/ZnS QDs layer not only works as an ETL but also has down-shifting property, which can improve both efficiency and stability of the PSCs. Using CdSe/ZnS QDs ETL with green emission, a PSC with maximum power conversion efficiency (PCE) of 18% is achieved. More importantly, our device shows great UV stability much better than the device with TiO2 ETL, where it retains 90% of its initial PCE value after 75 h under continuous UV illumination.
关键词： down-shifting layer,perovskite,solar cell,CdSe/ZnS QDs,stability,UV stability
更新于2025-09-23 15:19:57
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Green emitted CdSe@ZnS quantum dots for FLIM and STED imaging applications
摘要： Inorganic quantum dots (QDs) have excellent optical properties, such as high fluorescence intensity, excellent photostability and tunable emission wavelength, etc., facilitating them to be used as labels and probes for bioimaging. In this study, CdSe@ZnS QDs are used as probes for Fluorescence lifetime imaging microscope (FLIM) and stimulated emission depletion (STED) nanoscopy imaging. The emission peak of CdSe@ZnS QDs centered at 526 nm with a narrow width of 19 nm and the photoluminescence quantum yield (PLQY) was 64%. The QDs presented excellent anti-photobleaching property which can be irradiated for 400 min by STED laser with 39.8 mW. The lateral resolution of 42.0 nm is demonstrated for single QDs under STED laser (27.5 mW) irradiation. Furthermore, the CdSe@ZnS QDs were for the first time used to successfully label the lysosomes of living HeLa cells and 81.5 nm lateral resolution is obtained indicating the available super-resolution applications in living cells for inorganic QD probes. Meanwhile, Eca-109 cells labeled with the CdSe@ZnS QDs was observed with FLIM, and their fluorescence lifetime was around 3.1 ns, consistent with the in vitro value, suggesting that the QDs could act as a satisfactory probe in further FLIM-STED experiments.
关键词： CdSe@ZnS QDs,living cells,STED,FLIM
更新于2025-09-19 17:13:59
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Stable and efficient hybrid Ag-In-S/ZnS@SiO2-carbon quantum dots nanocomposites for white light-emitting diodes
摘要： As a promising energy-saving technique, the eco-friendly and low-cost solid-state white light-emitting diodes (WLEDs) based on quantum dots (QDs) have been widely studied. Herein, a WLED device prepared by core–shell structure nanocomposites based on Ag-In-S/ZnS@SiO2 quantum dots (AIS@SiO2) and carbon quantum dots (CDs) was successfully constructed. CDs were combined onto the surface of AIS@SiO2 QDs to synthesize Ag-In-S/ZnS@SiO2-Carbon quantum dots (AIS-CDs) nanocomposites with a white-light emission, which successfully overcome the quenching effect of CDs induced by conventional aggregation. The as-prepared AIS-CDs nanocomposites presented high stability and a photoluminescence quantum yield (PLQY) of 35%. Moreover, the corresponding AIS-CDs nanocomposites-based WLEDs demonstrated the color coordinate of (0.32, 0.33), which is comparable to the pure white light (0.33,0.33); Furthermore, the luminous efficiency of the as-prepared WLEDs showed 15.1 lm W-1. These results reported herein may open up a new avenue for the development of high-performance, low-cost, and environmentally-friendly WLEDs.
关键词： WLEDs,Ag-In-S/ZnS QDs,Nanocomposites,CDs
更新于2025-09-19 17:13:59
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Effect of surface ligands with different terminal group on the optical stability and cytotoxicity of CuInS <sub/>2</sub> /ZnS quantum dots with the crystal structure of sphalerite
摘要： A novel method for preparing CuInS2/ZnS quantum dots (CuInS2/ZnS QDs) with the crystal structure of sphalerite by one-pot hot injection was developed in this paper. The as-prepared core CuInS2 quantum dots (CuInS2 QDs) was uniform spherical nanoparticle with the average diameter of about 2 nm with the ?uorescent quantum yields (QY) of about 2.6%. By capping a shell of ZnS on the surface of CuInS2 QDs, the formed CuInS2/ZnS QDs exhibited obvious enhanced ?uorescent emission with the QY of about 20%. Intriguingly, the crystal structure of obtained CuInS2/ZnS QDs is sphalerite, which was con?rmed by XRD. Considering the different terminal group between these small organic molecules, mercaptoacetic acid (TGA), thioglycerol (TGC) and mercaptoethylamine (MEA) were further selected as capping molecules to exchange the surface ligands of CuInS2/ZnS QDs. The obtained CuInS2/ZnS QDs modi?ed with TGC exhibited excellent photostability in physiological conditions. To investigate the effect of ligand molecules on the biocompatible of CuInS2/ZnS QDs, the experiment on the cytotoxicity of CuInS2/ZnS QDs to A549 cells were conducted. The results indicated that CuInS2/ZnS QDs capped with TGC showed the lowest cytotoxicity while CuInS2/ZnS QDs capped with MEA exhibited the highest cytotoxicity among the three types of CuInS2/ZnS QDs modi?ed with ligands with different terminal group. These results provided a sight on how to select surface ligands to modify CuInS2/ZnS QDs when CuInS2/ZnS QDs will apply in biological ?elds.
关键词： sphalerite,photostability,CuInS2/ZnS QDs,cytotoxicity,surface ligands
更新于2025-09-16 10:30:52
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Development of Ratiometric Fluorescence Sensors Based on CdSe/ZnS Quantum Dots for the Detection of Hydrogen Peroxide
摘要： In this study, carboxyl group functionalized-CdSe/ZnS quantum dots (QDs) and aminofluorescein (AF)-encapsulated polymer particles were synthesized and immobilized to a sol–gel mixture of glycidoxypropyl trimethoxysilane (GPTMS) and aminopropyl trimethoxysilane (APTMS) for the fabrication of a hydrogen peroxide-sensing membrane. CdSe/ZnS QDs were used for the redox reaction of hydrogen peroxide (H2O2) via a reductive pathway by transferring electrons to the acceptor that led to fluorescence quenching of QDs, while AF was used as a reference dye. Herein, the ratiometric fluorescence intensity of CdSe/ZnS QDs and AF was proportional to the concentration of hydrogen peroxide. The fluorescence membrane (i.e., QD–AF membrane) could detect hydrogen peroxide in linear detection ranges from 0.1 to 1.0 mM with a detection limit (LOD) of 0.016 mM and from 1.0 to 10 mM with an LOD of 0.058 mM. The sensitivity of the QD–AF membrane was increased by immobilizing horseradish peroxidase (HRP) over the surface of the QD–AF membrane (i.e., HRP–QD–AF membrane). The HRP–QD–AF membrane had an LOD of 0.011 mM for 0.1–1 mM H2O2 and an LOD of 0.068 mM for 1–10 mM H2O2. It showed higher sensitivity than the QD–AF membrane only, although both membranes had good selectivity. The HRP–QD–AF membrane could be applied to determine the concentration of hydrogen peroxide in wastewater, while the QD–AF membrane could be employed for the detection of α-ketobutyrate.
关键词： ratiometric fluorescence QD membrane,CdSe/ZnS QDs,hydrogen peroxide,α-ketobutyrate,redox reaction
更新于2025-09-12 10:27:22
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Nitrogen donor ligand for capping ZnS quantum dots: a quantum chemical and toxicological insight
摘要： Nanoparticles having strong optical and electronic properties are the most widely used materials in sensor development. Since the target analyte interacts directly with the surface of the material, the choice of ligand for functionalizing the surface of the material is the key for its further applications. The functionalized surface of the material makes it suitable for required applications as it controls the size of the particle during its growth from the solution phase. Biomolecule capped nanomaterials are favourable for various applications in bio-sensing. In the present work, an attempt has been made to explore the biologically active molecule imidazole as capping agent for ZnS semiconductor nanoparticles or quantum dots (QDs). This work explores the possibility of replacing conventional thiol-zinc bonding and hence paves new pathways for biomolecules having the possibility of being efficient capping agents. Computational chemistry has been used to study the mechanism of bonding between one of the nitrogen atoms of imidazole and the zinc ion of the ZnS QDs. The quantum chemical insight not only explores the most spontaneous interaction of zinc ion and imidazole molecule so as to act as an efficient capping agent but also explains the probable bonding site for nitrogen–zinc chemistry. The tailormade Mn doped ZnS QDs are one of the most promising materials for probe and sensor development. The ZnS core having non-toxicity and the emission in longer wavelength due to manganese makes this material highly useful biologically. The aqueous route of synthesis has been employed to obtain a highly homogeneous and pure material which was further characterized by UV (Ultra Violet spectroscopy), Spectrofluorometer, Transmission Electron Microscope and X-ray Diffraction. The toxicity at the cellular and genetic levels was also investigated to prove the potential of the imidazole capped Mn doped ZnS QD as a biocompatible material.
关键词： quantum chemical,Nitrogen donor ligand,biocompatibility,capping agent,toxicological insight,ZnS quantum dots,Mn doped ZnS QDs,aqueous synthesis,imidazole
更新于2025-09-11 14:15:04
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Photoluminescence Decay of Colloidal Quantum Dots: Reversible Trapping and the Nature of the Relevant Trap States
摘要： Interfaces are crucial factors in shaping the properties of colloidal quantum dots (QDs), in particular the size-dependent optical properties that are a hallmark of these materials. However, the role played by the interfaces associated with QDs on the kinetics of photoluminescence (PL) decay of these nanocrystals is not fully understood even for the most extensively investigated II-VI QDs. In particular, interfaces are a hotbed of trapping sites over which control is essential for efficient performance of QD-based devices, because traps condition PL lifetimes and may be related to PL intermittency. In this work, we analyze the room-temperature PL decay of drop-cast films of CdSe/ZnS QDs varying a number of factors (casting solvent, capping ligands, core/shell interface character). We show how the use of a function that accounts for reversible trapping of photogenerated charge carriers with physically meaningful parameters (time constant, trapping and detrapping rate constants, and average number of traps per QD) can provide valuable information concerning the relevant interfaces, and therefore the nature of the trap states, involved in the recombination of those charge carriers. This approach should be applicable to QDs of a variety of compositions as well as materials beyond inorganic semiconductors.
关键词： photoluminescence decay,trap states,reversible trapping,CdSe/ZnS QDs,colloidal quantum dots
更新于2025-09-11 14:15:04