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Facile Preparation of Highly Luminescent Nitrogen-Doped Carbonaceous Nanospheres and Potential Application in Intracellular Imaging of Quercetin
摘要： Highly luminescent nitrogen-doped carbonaceous nanospheres (LNCNs) were synthesized by a one-pot hydrothermal reaction of b-cyclodextrin (b-CD) and branched polyethylenimine (BPEI). Both the N-doping and amino-functionalisation of LNCNs were achieved simultaneously. The prepared LNCNs display excellent properties such as high physical and chemical stability, excitation wavelength-independent emission, and high photoluminescence quantum yields. Importantly, the LNCNs exhibit a quenching of photoluminescence in the presence of quercetin (Qc) based on the simple static quenching mechanism, making it possible to quantify concentrations from 0.5 to 80 mg mL(cid:1)1 with a detection limit of 0.21 mg mL(cid:1)1. Furthermore, the LNCNs probe was further used for imaging Qc in living cells.
关键词： quercetin,photoluminescence quenching,nitrogen-doped carbonaceous nanospheres,intracellular imaging
更新于2025-09-23 15:21:01
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Novel Immunochromatography Assay Based on Background Fluorescence Quenching for the Sensitive Determination of Serum Cystatin C
摘要： In this study, a novel immunochromatographic method has been established to achieve quantitative detection of serum cystatin C. Unlike conventional and traditional gold immune chromatographic assays (GICAs), a uniform layer of a fluorescent film was added to the solid phase, which has been designated as the background fluorescence quenching immune chromatographic assay (bFQICA). Under the optimized conditions, there was a good correlation between the fluorescence signal ratio (F1/F2) of the background fluorescence (F1) to the fluorescence signal at the detection line (F2) for cystatin C at concentrations from 0.0 ng/mL to 100 ng/mL with a correlation coefficient of 0.9977. The detection limit was 0.69 ng/mL, and the recovery values were 87.9–105%. The differences between the intra- and interbatch precision were less than 15% in three batches. In addition, after 120 serum samples were detected, there were no significant differences in the results obtained by bFQICA and immunoturbidimetry (t ? 0.963, p ? 0.338 > 0.05). This work demonstrates that bFQICA is a simple, sensitive, and accurate approach for the determination of serum cystatin C, providing a new approach for the clinical diagnosis of cystatin C.
关键词： gold immune chromatographic assay,cystatin C,Background fluorescence quenching immune chromatographic assay
更新于2025-09-23 15:21:01
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A trigonal dodecahedral cadmium(II) complex with zinc(II)-salen type metalloligand: Synthesis, structure, self-assembly and application in the detection of various nitroaromatics via turn-off fluorescence response
摘要： A compartmental Schiff base ligand, N,N'-bis(3-ethoxysalicylidene)-2,2-dimethylpropane-1,3-diamine (H2L) has been used to prepare a hetero-trimetallic cadmium(II)/zinc(II) complex, Cd{LZn(NCS)}2. Single crystal X-ray diffraction analysis has confirmed the structure of the complex. Cadmium(II) is octa-coordinated and it shows trigonal dodecahedral geometry. The complex behaves as a sensor for the detection of various nitroaromatics via turn-off fluorescence response.
关键词： Hetero-trimetalllic complex,Fluorescence quenching,Compartmental Schiff base
更新于2025-09-23 15:21:01
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Temperature-dependent luminescence of Ce-doped SrO-B2O3 glasses
摘要： In this study, the photoluminescence (PL) and X-ray-induced scintillation of trivalent cerium, Ce3+, in strontium borate glasses was examined. As no precipitated crystallites were observed, the slight coloration of the glasses was attributed to the formation of defects that are inactive in electron spin resonance spectroscopy. Both the Ce3+/(Ce3++Ce4+) ratio, which was estimated based on the Ce LIII-edge in X-ray absorption near edge structure analysis, and the internal quantum efficiency of Ce-doped glasses increased as the amount of Ce(OCOCH3)3×H2O, which acted as a reducing agent, was increased. Although the PL intensity was independent of the temperature in the range of 10–300 K, the X-ray induced scintillation exhibited thermal quenching behavior with an activation energy of 0.14 eV.
关键词： borate glass,scintillation,thermal quenching,Ce L-edge X-ray absorption near edge structure (XANES),photoluminescence,cerium
更新于2025-09-23 15:21:01
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Studies on the Interaction of Cefepime Hydrochloride with Bovine Serum Albumin by Fluorescence, Synchronous Fluorescence, Three-Dimensional Fluorescence and Circular Dichroism
摘要： The investigation on the binding mode between drug and protein is extremely important to understand biopharmaceutics, pharmacokinetics and toxicity of the drug as well as the relationship of structure and function of the protein. It is well proved that biological activity is a function of the chemical structure or structural properties. There is a study on the interaction of cefepime hydrochloride with serum albumin using in-silico molecular docking. But up to date, there is hardly any interaction investigation of cefepime hydrochloride with serum albumin utilizing by fluorescence, synchronous fluorescence, three-dimensional fluorescence and circular dichroism. In this study, the interaction of cefepime hydrochloride with bovine serum albumin in aqueous solution has been investigated by molecular spectroscopy under different pH conditions. The quenching rate constant and binding constant calculated at pH 7.4 indicated the static quenching mechanism and medium binding force. The effect of cefepime hydrochloride on the conformation of bovine serum albumin was analyzed using fluorescence, synchronous fluorescence, three-dimensional fluorescence and circular dichroism. In addition, influence of pH on the binding of cefepime hydrochloride to bovine serum albumin was investigated and the binding ability of the drug to bovine serum albumin deceased under other pH conditions (pH 1.9, 3.5, and 9.0) as compared with that at pH 7.4. As compared with the binding ability of cefepime hydrochloride to native bovine serum albumin that of cefepime hydrochloride to denatured bovine serum albumin deceases dramatically. Furthermore, the effect of metal ions on the binding constant of cefepime hydrochloride with bovine serum albumin was investigated.
关键词： Circular dichroism,Fluorescence quenching,Bovine serum albumin,Three-dimensional fluorescence,Cefepime hydrochloride
更新于2025-09-23 15:21:01
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pH and Thermo Dual-Responsive Fluorescent Hydrogel Actuator
摘要： As one of the most important smart materials, fluorescent hydrogel actuators can produce both color and shape changes under external stimuli. In the present work, an effective approach to develop a novel fluorescent hydrogel actuator with pH and thermo dual responsiveness is proposed. Through incorporating pH-responsive perylene tetracarboxylic acid (PTCA), which is a typical fluorescent moiety with aggregation-caused quenching (ACQ) effect, into an anisotropic poly(N-isopropylacrylamide)–polyacrylamide (PNIPAm-PAAm) structure, the obtained hydrogel exhibits stable thermoresponsive shape deformation and switchable fluorescence performance upon a pH trigger. Therefore, fluorescence-quenching-based and actuation-based information can be revealed when exposed to UV light and immersed into warm water, respectively. Moreover, the thermoresponsive actuating behavior can be applied to further hide the fluorescence-quenching-based images. The present work may provide new insights into the design and preparation of novel stimuli-responsive hydrogel actuators.
关键词： anisotropic structures,hydrogel actuators,fluorescence quenching,shape deformation
更新于2025-09-23 15:21:01
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Light-Triggered Dual-Modality Drug Release of Self-Assembled Prodrug-Nanoparticles for Synergistic Photodynamic and Hypoxia-Activated Therapy
摘要： Photodynamic therapy (PDT) leads to tumor hypoxia which could be utilized for the activation of hypoxia-activated prodrugs (HAPs). However, conventional photosensitizer-loaded nanoformulations suffer from aggregation-caused quenching (ACQ) effect, which limits the efficiency of PDT and synergistic therapy. Herein, prodrug-nanoparticles (NPs) are prepared by the self-assembly of heterodimeric prodrugs composed of pyropheophorbide a (PPa), hypoxia-activated prodrug PR104A, and a thioether or thioketal linkage. In addition, a novel dual-modality drug release pattern is proposed on the basis of the structural states of prodrug-NPs. Under light irradiation, PR104A is released via photoinduced electron transfer (PET) due to the aggregating state of prodrugs. With the disassembly of prodrug-NPs, ACQ effect relieves, PPa produces singlet oxygen which further promotes the reactive oxygen species (ROS)-sensitive release of PR104A. Such prodrug-NPs turn the disadvantage of the ACQ effect to facilitate drug release, demonstrating high-efficiency synergy in combination with PDT and hypoxia-activated therapy.
关键词： aggregation-caused quenching,Photodynamic therapy,drug release,photoinduced electron transfer,hypoxia-activated prodrugs,reactive oxygen species
更新于2025-09-23 15:19:57
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Stable nano-silver colloid production via Laser Ablation Synthesis in Solution (LASiS) under laminar recirculatory flow
摘要： As nanomaterials find applications in an increasingly diverse range of fields such as wastewater treatment, biotechnology and flexible electronics, the demand for nanomaterials with specific properties has increased. This increase is coupled with an increasing emphasis on nanomaterials with highly specific properties for specialised applications. Industrially, nanomaterials are produced via wet-chemical techniques which employ the use of solvents and reagents which are environmentally harmful. As we move forward with the use of nanomaterials, the ability to produce nanomaterials in a sustainable manner has become a topic of great significance. Towards this end, Laser Ablation Synthesis in Solution (LASiS) is a physical production technique capable of producing tailored nanomaterial colloids in a sustainable manner. These colloids are produced by ablating a solid target immersed in a solvent using a laser. Typically, LASiS is conducted in a batch process and in small volumes limiting commercial viability. To overcome this, there has been a move towards the use of continuous production via LASiS using flow systems. This allows an increase in nanomaterial yield, resulting in colloid concentrations approaching those of commercial colloids. This work investigates a new production technique incorporating a laminar recirculatory flow system to produce stable high concentration nano-silver colloids.
关键词： silver,Nanoparticle,laser ablation synthesis in solution,size-quenching
更新于2025-09-23 15:19:57
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Surface-plasmon-enhanced optical formaldehyde sensor based on CdSe@ZnS quantum dots
摘要： For the first time, a reproducible surface-plasmon-enhanced optical sensor for the detection of gaseous formaldehyde was proposed by depositing the mixture of CdSe@ZnS quantum dots (QDs), fumed silica (FS) and gold nanoparticles (GNs) on the surface of silica spheres array to meet the urgent requirement of a rapid, sensitive, and highly convenient formaldehyde detection method. Due to the spectra overlap between QDs and GNs, plasmon-enhanced fluorescence was observed in the film of QDs/FS/GNs. When exposing to formaldehyde molecules, the enhanced fluorescence was quenched linearly with the increase of formaldehyde concentration in the range of 0.5-2.0 ppm. The reason is attributed to the nonradiative electron transfer from QDs to the carbonyl of formaldehyde molecules with the assistance of amino groups. Our results demonstrate that the designed sensors are capable of detecting ultralow concentration gaseous formaldehyde at room temperature with a fast response-recovery time, excellent selectivity, stability and reproducibility. This work provides a simple and low-cost approach for optical formaldehyde sensor fabrication and shows promising applications in environmental detection.
关键词： plasmon-enhanced fluorescence,Quantum dots,reproducibility,Optical formaldehyde sensors,fluorescence quenching
更新于2025-09-23 15:19:57
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Multiscale Simulation of Photoluminescence Quenching in Phosphorescent OLED Materials
摘要： A multiscale simulation protocol to treat triplet–triplet annihilation (TTA) in phosphorescent organic light-emitting diodes (PhOLEDs), in which microscopic parameters are computed with ab initio electronic structure methods, is presented. Virtual photoluminescence experiments are performed on a prototypical PhOLED emission material consisting of 4,4?,4?-tris(N-carbazolyl)triphenylamine and fac-tris(2-phenylpyridine)iridium. The obtained TTA quenching rate is comparable to experimental results in the low-intensity limit.
关键词： multiscale modeling,organic light-emitting diodes,exciton quenching,triplet–triplet annihilation
更新于2025-09-23 15:19:57