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One-pot green synthesis of highly luminescent silicon nanoparticles using Citrus limon (L.) and their applications in luminescent cell imaging and antimicrobial efficacy
摘要： Strongly luminescent and water dispersible silicon nanoparticles were synthesised by one-pot synthesis from venyl-trimethoxy-silane and (3-aminopropyl)-triethoxy-silane using both chemical and green reducing agents, sodium ascorbate and Citrus limon (L.) respectively. Unlike sodium ascorbate, the reduction using lemon extracts produces smaller nanoparticles with average size of 20 and 57 nm. The antimicrobial e?cacy of the nanoparticles is examined against various microorganisms and is noted that these particles possessed antibacterial property if used in concentrations above the threshold value of 1.5 μg/ml. In addition, these silicon nanoparticles emit intense blue-green emission which is successfully utilised for the luminescent cell imaging of human white blood cells and mice epithelial cells.
关键词： Luminescence,Citrus limon (L.),Silane,Silicon nanoparticle,Cell imaging.
更新于2025-09-23 15:23:52
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Challenges in semiconductor single entity photoelectrochemistry
摘要： It is challenging to study the single semiconductor (SC) nanocrystal electrochemistry and photoelectrochemistry. The photocatalytic process that results from the electron-hole pair formed within a nanoparticle (NP) like the oxidation of methanol and iodide allow the detection of discrete current transient events assigned to single entities. Photocatalytic current amplification allows detection of collisions between the semiconductor NPs and the ultramicroelectrode (UME) that produce current transient. Staircase responses and blips in the i vs. t response indicate that irreversible and reversible NP/electrode interactions result depending on the experimental conditions. Dye sensitization increases the photocurrent magnitude of ZnO and TiO2 with respect to bare TiO2 NPs. The microelectrodes used are Pt, TiO2/Pt, TiO2/Au and F-doped SnO2 (FTO).
关键词： semiconductor,photoelectrochemistry,ultramicroelectrode,nanoparticle,dye sensitization,single entity
更新于2025-09-23 15:23:52
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Reproduction of surface-enhanced resonant Raman scattering and fluorescence spectra of a strong coupling system composed of a single silver nanoparticle dimer and a few dye molecules
摘要： The spectral changes in surface-enhanced resonant Raman scattering (SERRS) and surface enhanced fluorescence (SEF) of single silver nanoparticle dimers adsorbed by near-single dye molecules are reproduced under strong coupling regimes. For the reproduction, the enhancement and quenching factors in SERRS and SEF are derived from the Purcell factors including both radiative and nonradiative plasmon modes. The Purcell factors are estimated using the coupling energies obtained by analyzing the spectral changes in plasmon resonance during SERRS and SEF decay processes on the basis of a classical hybridization model. The model is composed of a plasmon and a molecular exciton with phonon replicas accurately representing the molecular multi-level system. The reproduced SERRS spectral changes are consistent with the experimental ones. Furthermore, the calculated SEF spectral changes can reproduce the experimental ones by phenomenologically assuming transitions from ultra-fast SEF to conventional SEF with decreasing coupling energies.
关键词： strong coupling,hybridization model,silver nanoparticle dimer,dye molecules,Purcell factors,surface enhanced fluorescence,surface-enhanced resonant Raman scattering
更新于2025-09-23 15:23:52
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Double-function SiO2-DMS coating with antireflection and superhydrophobic surface
摘要： A double-function SiO2 coating with antireflection and superhydrophobic properties was fabricated through a cost-effective and time-efficient sol-gel method. Tetraethoxysilane was used as a precursor to obtain SiO2 with an antireflection property. Hexamethyldisilazane was used as a modifier to produce SiO2-DMS with a superhydrophobic behaviour. The SiO2-DMS coating had a water contact angle of 153° and a water slide angle of <10°. The optimised SiO2-DMS coating had an average transmittance of 96.07% at a wavelength of 300-800 nm. The entire process could be completed in a short time.
关键词： nanoparticle,sol-gel method,superhydrophobic,antireflection
更新于2025-09-23 15:23:52
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Determination of 17β-estradiol by surface-enhanced Raman spectroscopy merged with hybridization chain reaction amplification on Au@Ag core-shell nanoparticles
摘要： The authors describe an aptamer-based assay for 17β-estradiol. It relies on the combined use of surface enhanced Raman scattering (SERS) and hybridization chain reaction (HCR). The aptamer against 17β-estradiol is applied as the recognition probes, and this results in excellent specificity. Specific recognition of target 17β-estradiol induce the freedom of DNA 2, which will open the stem-loop structure of probe 1 on the Au@Ag and form the partial dsDNA structure. With the nicking enzyme, the partial dsDNA will be hydrolyzed and the reside ssDNA on Au@Ag will form a small stem-loop structure. With the help of the other probe 2 modified Au@Ag and pre-immobilized probe 3 on the well of the microplate, an enzyme-free HCR can occur and tremendous Au@Ag can be assembled along the formed dsDNA in HCR, which can act as the excellent substrate for Raman measurement and greatly amplify the Raman signal of R6G on the Au@Ag. Afterwards, the key factor, ratio between probe 2-Au@Ag (P2) and probe1-Au@Ag (P1), affects the detection sensitivity is systematically optimized for the best sensing performance. The SERS signal of R6G, best measured at 1651 cm?1, increases linearly in the wide range from 1 pM to 10 nM. The detection limit can be as low as 0.1 pM.
关键词： Estrogen,Hybridization chain reaction,SERS,Food safety,Aptamer,Gold nanoparticle,Signal amplification,Environment monitoring
更新于2025-09-23 15:23:52
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Atomistic modeling of resistivity evolution of copper nanoparticle in intense pulsed light sintering process
摘要： In this work, the intense pulsed light (IPL) sintering process of copper nanoparticle ink is simulated using molecular dynamics (MD) method. First, the neck size growth between the two copper nanoparticles during the IPL sintering process is computed. The resultant electrical resistivity is then calculated by substituting the neck size into the Reimann-Weber formula. Overall, a rapid decrease of electric resistivity is observed in the beginning of the sintering, which is caused by quick neck size growth, followed by a gradually decrease of resistivity. In addition, the correlation of the simulated temperature dependent resistivity is similar to that of the experimentally measured resistivity. The MD model is an effective tool for designers to optimize the IPL sintering process.
关键词： Molecular dynamics,Nanoparticle,Electrical resistivity,Intense pulsed light,Copper
更新于2025-09-23 15:23:52
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Fabrication of Remarkably Bright QD Densely-Embedded Silica Nanoparticle
摘要： We developed a synthesis method for silica-coated quantum dot (QD)-densely-embedded silica nanoparticle (Si@D-QD@Si NP) with remarkably brighter fluorescence by increasing the number of QDs on silica NPs. Si@D-QD@Si NPs exhibited a narrow size distribution and a high signal reproducibility. Red, green, and blue Si@D-QD@Si NPs were successfully fabricated and characterized. The Si@D-QD@Si NP carried 2.4 times more QDs than previously reported silica-coated QD-embedded silica NP (Si@QD@Si NP). The quantum yield of Si@D-QD@Si NPs was slightly higher than Si@QD@Si NPs. The red Si@D-QD@Si NPs showed approximately 26.6%, the green Si@D-QD@Si NP 36.2%, and the blue Si@D-QD@Si NP 39.3% higher fluorescence intensity compared to the corresponding Si@QD@Si NPs. This result implied that the particles can be used at bio-field with a higher sensitive detection.
关键词： Quantum dot,Quantum yield,Fluorescence,Silica coating,Silica nanoparticle
更新于2025-09-23 15:23:52
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UV Illumination-Enhanced Molecular Ammonia Detection Based On a Ternary-Reduced Graphene Oxide–Titanium Dioxide–Au Composite Film at Room Temperature
摘要： In this work, we report on UV illumination enhanced room-temperature trace NH3 detection based on ternary composites of reduced graphene oxide nanosheets (rGO), titanium dioxide nanoparticles (TiO2) and Au nanoparticles as the sensing layer, which is firstly reported by far. The effect of UV state as well as componential combination and content on the sensing behavior disclosed that, rGO nanosheets served as not only a template to attach TiO2 and Au, but an effective electron collector and transporter; TiO2 nanoparticles acted as a dual UV and NH3 sensitive material; Au nanoparticles could increase the sorption sites and promote charge separation of photoinduced electron-hole pairs. The as-prepared rGO/TiO2/Au sensors were endowed with a sensing response of 8.9% toward 2 ppm NH3, a sensitivity of 1.43×10-2/ppm within the investigated range, nice selectivity, robust operation repeatability and stability, which was fairly competitive in comparison with previous work. Meanwhile, the experimental results provided clear evidence of inspiring UV-enhanced gas detection catering for the future demand of low power-consumption and high sensitivity.
关键词： Room temperature.,Gas sensor,Reduce graphene oxide,Ammonia,Au nanoparticle,Titanium dioxide,UV illumination
更新于2025-09-23 15:23:52
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NIR-Responsive Copolymer Upconversion Nanocomposites for Triggered Drug Release in Vitro and in Vivo
摘要： Light has several advantages as the stimulus for triggered drug release. Currently, the applications of phototriggered drug-release devices (PDDs) are largely limited by two factors: the limited tissue penetration and detrimental effects caused by excitation light (ultraviolet or visible light). To address this disadvantage, this study developed nanocomposites based on upconversion nanoparticles (UC), which could convert near-infrared light to ultraviolet-visible light and trigger drug release. By loading UC and doxorubicin (DOX) into photo-responsive copolymer PEG-NMAB-PLA (PNP), near-infrared responsive copolymer upconversion nanocomposites (PNP-DOX-UC) was constructed. We proved that PNP-DOX-UC showed the fast release and strong cytotoxicity under near infrared irradiation in vitro. The therapeutic efficacy study indicated that PNP-DOX-UC+hv had the enhanced antitumor efficiency. In the study, UC becoming an internal ultraviolet-visible light source for near infrared excitation developes an applicable and efficient approach to meet the requirements for UV/Vis excitation, which is a major disadvantage in photosensitive materials developed for pharmaceutical and biomedical applications.
关键词： Near-infrared light,Photo-responsive,Nanocomposites,Copolymer,Triggered drug release,Upconversion Nanoparticle
更新于2025-09-23 15:23:52
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Porous SiO2-coated Au-Ag alloy nanoparticles for the alkyne-mediated ratiometric Raman imaging analysis of hydrogen peroxide in live cells
摘要： We prepared an ultrathin porous silica shell-coated Au-Ag alloy nanoparticle (AuAg@p-SiO2NP) and developed it as a novel alkyne-based surface-enhanced Raman scattering (SERS) nanoprobe for the ratiometric Raman imaging of exogenous and endogenous H2O2 in live cells. The AuAg@p-SiO2NPs functionalized with 4-mercaptophenylboronic acid (MPBA) and 4-mercaptophenylacetylene (MPAE, 1,986 cm-1) as internal standard were first incubated with dopamine (DA) to incorporate the bridging molecules through the formation of borate bond between DA and MPBA on the surface of nanoparticle. Then, the signaling alkyne molecules of 3-(4-(phenylethynyl) benzylthio) propanoic acid (PEB, 2,214 cm-1) were conjugated to the surface of nanoparticle through the formation of amide bond between the carboxyl group on the PEB and the amino group on the DA, forming the ratiometric SERS nanoprobe. In the presence of H2O2, the alkynyl on the PEB is released from the surface of the Au-Ag alloy nanoparticle due to the boronate-to-phenol switch, decreasing the Raman signal at 2,214 cm-1 significantly. Since the Raman signal of MPAE at 1,986 cm-1 remains unchanged, quantitative analysis of H2O2 concentration can be achieved based on the ratiometric value of I1986/I2214. Under the optimized conditions, the plot of the ratiometric value of I1986/I2214 versus the H2O2 concentration in the range from 0.12 to 8 m M revealed a good linear response with a detection limit of 52 nM based on a signal-to-noise ratio of S/N = 3. The porous SiO2-coated Au-Ag alloy nanoparticle provides a novel SERS substrate with excellent biocompatibility, high stability, and effective anti-interference ability. Together with the alkynyl derivatives as internal standard, the SERS nanoprobe reported here allows the ratiometric detection of H2O2 in live cells and can be further applied to quantify many other biomolecules by using different signaling agents.
关键词： porous SiO2-coated Au-Ag alloy nanoparticle,SERS,alkyne,cell imaging,hydrogen peroxide
更新于2025-09-23 15:23:52