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A magnetic and carbon dot based molecularly imprinted composite for fluorometric detection of 2,4,6-trinitrophenol
摘要： A magnetic molecularly imprinted composite was prepared by reverse microemulsion using carbon dots (CDs), Fe3O4 as the co-nucleus, and a molecularly imprinted polymer (MIP; with 2,4,6-trinitrophenol as the template) acting as recognition sites. The composite of type CD/Fe3O4@MIPs was characterized by transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), zeta potentiometric analysis, X-ray diffraction (XRD) and vibrating sample magnetometry (VSM). The results showed that the composite MIP has a spherical shape with average diameter of 200 nm. They also showed that the composite contains core-shell structures with several Fe3O4 nanoparticles and CDs embedded in each of the microsphere. The composite can extract 2,4,6-trinitrophenol (TNP) and has an imprinting factor of 3.6. It has high selectivity and sensitivity for TNP which acts as a quencher of the fluorescence of the CDs (with excitation/emission maxima at 370/470 nm). The limit of detection of this fluorometric TNP assay is 0.5 nM. The method was successfully applied to the determination of TNP in spiked tap water and river water samples, and recoveries ranged from 89.4% to 108.5% (with an RSD of <6%).
关键词： Fluorescence quenching,Fe3O4 nanoparticles,Stern-Volmer plot,Environmental pollutants,Reverse microemulsion method,Selective recognition,Molecularly imprinting
更新于2025-09-23 15:23:52
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Structural, optical and magnetic elucidation of co-doped of Nd+3 and Pr+3 on lithium nanoferrites and its technological application
摘要： LiNiCo spinel ferrites were prepared, by doping with rare earth metals Nd and Pr, according to micro-emulsion method. In order to study the effect of Nd and Pr, the crystal structure and magnetic properties of prepared ferrites were scrutinized in detail. The endorsement of single-phase spinel ferrites with the co-occurrence of orthophase was confirmed by XRD and FTIR. The average crystallite size varied with increasing the doped concentration of Nd and Pr, which is in the range from 28nm to 70nm. Magnetic properties were analyzed by VSM within range of -10000Oe and 10000Oe. MS and MR values decreased with the increase in concentration. The value of HC, MR, and MS showed stability for transformer core where electromagnetic interference is reduced. Hence synthesized ferrites LiNi0.35-yCo0.15PryNdxFe2-xO4 are suitable for transformers and induction.
关键词： Microemulsion,XRD,Li-Pr,Neodymium,Nanocrystalline ferrites,Praseodymium,Magnetic properties
更新于2025-09-23 15:23:52
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Tailored Engineering of Bimetallic Plasmonic Au@Ag Core@Shell Nanoparticles
摘要： A distinctive synthetic method for the efficient synthesis of multifunctional bimetallic plasmonic Au@Ag core@shell nanoparticles (NPs) with tunable size, morphology, and localized surface plasmon resonance (LSPR) using Triton X-100/hexanol-1/deionized water/cyclohexane-based water-in-oil (W/O) microemulsion (ME) is described. The W/O ME acted as a “true nanoreactor” for the synthesis of Au@Ag core@shell NPs by providing a confined and controlled environment and suppressing the nucleation, growth, agglomeration, and aggregation of the NPs. High-resolution transmission electron microscopic analysis of the synthesized Au@Ag core@shell NPs revealed an “unusual core@shell” contrast, and the selected area electron diffraction and Moiré patterns showed that Au layers are paralleled to Ag layers, thus indicating the formation of Au@Ag core@shell NPs. Interestingly, the UV?visible spectrum of the Au@Ag core@shell NPs exhibited enthralling plasmonic properties by introducing a high-frequency quadrupolar LSPR mode originated from the isolated Au@Ag NPs along with a low-frequency dipolar LSPR mode originated from the coupled Au@Ag NPs. The effective plasmonic enhancement of the Au@Ag core@shell NPs is attributed to the extreme enhancement of the localized electromagnetic field by coupling of the localized surface plasmons of the Au core and Ag shell. The mechanisms for the nucleation and growth of Au@Ag core@shell NPs in W/O ME have been proposed. A unique electron transfer phenomenon between the Au core and Ag shell is elucidated for better understanding and manipulation of the electronic properties, which evinced the development of Au@Ag core@shell NPs through suppression of the galvanic replacement reaction.
关键词： localized surface plasmon resonance,Au@Ag core@shell,bimetallic plasmonic nanoparticles,electron transfer phenomenon,water-in-oil microemulsion
更新于2025-09-23 15:19:57
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Size-Controlled Synthesis of Pt Particles on TiO2 Surface: Physicochemical Characteristic and Photocatalytic Activity
摘要： Different TiO2 photocatalysts, i.e., commercial samples (ST‐01 and P25 with minority of rutile phase), nanotubes, well‐crystallized faceted particles of decahedral shape and mesoporous spheres, were used as supports for deposition of Pt nanoparticles (NPs). Size‐controlled Pt NPs embedded in TiO2 were successfully prepared by microemulsion and wet‐impregnation methods. Obtained photocatalysts were characterized using XRD, TEM, X‐ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) specific surface area, DR/UV‐vis and action spectrum analysis. The effect of deposition method, amount of Pt precursor and TiO2 properties on size, distribution, and chemical states of deposited Pt NPs were investigated. Finally, the correlations between the physicochemical properties and photocatalytic activities in oxidation and reduction reactions under UV and Vis light of different Pt‐TiO2 photocatalysts were discussed. It was found that, regardless of preparation method, the photoactivity mainly depended on platinum and TiO2 morphology. In view of this, we claim that the tight control of NPs’ morphology allows us to design highly active materials with enhanced photocatalytic performance. Action spectrum analysis for the most active Pt‐modified TiO2 sample showed that visible light‐induced phenol oxidation is initiated by excitation of platinum surface plasmon, and photocatalytic activity analysis revealed that photoactivity depended strongly on morphology of the obtained Pt‐modified TiO2 photocatalysts.
关键词： titania morphology,microemulsion,platinum size,Pt‐TiO2,TiO2 particle size,heterogeneous photocatalysis
更新于2025-09-12 10:27:22
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Simple preparation of fluorescence probe based on CdTe quantum dots combined with MIP for selective detection of sulfadimidine
摘要： A simple fluorescence sensor for the detection of sulfadimidine (SM2) was fabricated by molecular imprinting technology. Cadmium telluride quantum dots (CdTe QDs) as the fluorescent material, 3-aminopropyltriethoxysilane (APTES) as functional monomer, sulfadimidine as template molecule and tetraethoxysilane (TEOS) as cross-linker, the CdTe QDs were embedded in silica nano-particles by reverse microemulsion method. Under optimal detection condition, response is linear in the 2–30 μmol L?1 SM2 concentration condition with the detection limit was 0.4 μmol L?1. In addition, the correlation coefficient was 0.9857 and the imprinting factor was 4.82. The fluorescent probe was successfully applied to the determination of SM2 in tap water and milk sample with the spiked recoveries ranging from 99.8 to 103.2%. It gets a good specific recognition ability and potential practical application value.
关键词： reverse microemulsion method,molecular imprinting technology,sulfadimidine,CdTe quantum dots,fluorescence sensor
更新于2025-09-12 10:27:22
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Self-assembled quantum dot microstructure guided by a microemulsion approach for immunoassays
摘要： Quantum dot microstructures were fabricated through a convenient microemulsion approach in this study. A polymer solution containing a stabilizer was mixed with a quantum dot aqueous solution, to prepare a reversed microemulsion, through shaking. Then, the microemulsion was cast on a solid substrate followed by evaporating steps, resulting in the formation of an ordered porous film. Interestingly, the quantum dot microstructure can be produced at the same time. The immunoassay experiment could be realized by the fluorescent microstructures. The green fluorescence microstructure specifically bound with antigens marked with red color quantum dots, resulting in the enhancement of red fluorescence domains and the decrease of green fluorescence. With the addition of unlabeled antigens, the green fluorescence microstructure was recovered. This strategy implies that the quantum dot pattern has potential on biochip, biosensor, and imaging analysis.
关键词： immunoassay,microstructure,microemulsion,fluorescence,quantum dot
更新于2025-09-11 14:15:04
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Preparation of α-Linolenic-Acid-Loaded Water-in-Oil-in-Water Microemulsion and Its Potential as a Fluorescent Delivery Carrier with a Free Label
摘要： Our previous work has demonstrated that α-linolenic acid (ALA)-loaded oil-in-water (O/W) microemulsion could enhance ALA antioxidant capacity. Meanwhile, we also observed that synthesized microemulsion itself had ?uorescence. In this work, we have prepared a multiple water-in-oil-in-water (W/O/W) microemulsion to further enhance ALA antioxidant capacity and activate this delivery carrier application potential with a free label. The compositions of primary water-in-oil (W/O) microemulsion were obtained using pseudo-ternary phase diagrams, and then W/O/W microemulsion was prepared adopting the “two-step heterotherm method”. The conductivity of W/O/W microemulsion was measured to lie between 250.0 and 350.0 μs/cm. The spherical droplets with a mean particle diameter of 10.0?20.0 nm were con?rmed by transmission electron microscopy and dynamic light scattering. Nuclear magnetic resonance con?rmed that ALA di?used to the multiple water?oily interface simultaneously. In addition, the in vitro release and antioxidant capacity measurements of ALA-loaded W/O/W microemulsion concluded the sustained-release e?ect and excellent antioxidant capacity. The ?uorescent intensity of W/O/W microemulsion was markedly increased in comparison to O/W microemulsion. The synthesized microemulsion could lead to important applications and have advantages of a label-free ?uorescent carrier for optical imaging purposes.
关键词： ALA-loaded W/O/W microemulsion,?uorescent delivery carrier,characterization,antioxidant capacity
更新于2025-09-10 09:29:36
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Thermo‐sensitive nanogel‐laden bicontinuous microemulsion drug‐eluting contact lenses
摘要： The bicontinuous microemulsion contact lens (BMCL) has nanoporous biphasic structures (100–250 nm) that are interconnected via multiple nano-channels, providing suitable retention of various drugs for glaucoma. Timolol maleate (TM)-carried poly(N-isopropylacrylamide) (PNIPAM) nanogel (30–50 nm) was incorporated into BMCLs by soaking or by centrifuging plus soaking. Here, we present drug-loading and release in silicon- or polyethylene oxide-microemulsion BMCLs under various conditions. Nanoporous BMCLs containing thermosensitive TM-laden nanogel were capable of potent body-temperature-triggered release of TM. Daily drug release was controllable according to the initial volume of drug-loaded (VDL) and loading method for sustained drug release, making them reduce drug-loss during transportation or storage.
关键词： temperature-triggered drug release,sustained drug release,bicontinuous microemulsion,drug delivery,nanoporous contact lens,drug-eluting contact lens
更新于2025-09-04 15:30:14