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Fabrication of Gold Nanorods for SERS Detection of Thiabendazole in Apple
摘要： Thiabendazole (TBZ) is a kind of pesticide that is widely used in agriculture, and its residue may pose a threat to human health. In order to measure TBZ residues in food samples, a surface-enhanced Raman spectroscopy (SERS) method combined with a homogeneous and reusable gold nanorods (GNR) array substrate was proposed. GNR with a high uniformity was synthesized and then applied to the self-assembly of a GNR vertically aligned array. The relative standard deviation (RSD) of the array for SERS could reach 15.4%, and the array could be reused for more than seven times through the treatment of plasma etching. A logarithmic correlation between TBZ concentration and Raman intensity was obtained, with the best determination coefficient (R2) and the corresponding limit of detection (LOD) of 0.991 and 0.037 mg/L in methanol solution, and 0.980 and 0.06 ppm in apple samples, respectively. The recoveries of TBZ in apple samples ranged from 76% to 107%. This study provided a rapid and sensitive approach for detecting TBZ in apples based on SERS coupled with GNR array substrate, showing great potential for analyzing other trace contaminants in food.
关键词： Apple,Gold nanorods array,Surface enhanced Raman spectroscopy,Thiabendazole
更新于2025-09-10 09:29:36
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Photothermal Therapy Employing Gold Nanoparticle- Loaded Macrophages as Delivery Vehicles: Comparing the Efficiency of Nanoshells Versus Nanorods
摘要： Macrophages (Ma) loaded with gold-based nanoparticles, which convert near infrared light to heat, have been studied as targeted transport vectors for photothermal therapy (PTT) of tumors. The purpose of the experiments reported here was to compare the efficacy of gold-silica nanoshells (AuNS) and gold nanorods (AuNR) in macrophage-mediated PTT. Photothermal therapy efficacy was evaluated in hybrid glioma spheroids consisting of human glioma cells and either AuNS- or AuNR-loaded Ma, designated MaNS and MaNR, respectivly. Spheroids were irradiated for 10 minutes with light from an 810-nm diode laser at irradiances ranging from 0 to 28 W/cm2. Photothermal therapy efficacy was determined from spheroid growth over a 14-day period. The uptake by Ma of pegylated AuNR (3.9 ± 0.9 %) was twice that of pegylated AuNS (7.9 ± 0.7%). Hybrid spheroids consisting of a 5:1 ratio of glioma cells to loaded Ma exhibited significant growth inhibition with MaNS when subjected to irradiances of 7 W/cm2 or greater. In contrast, no significant growth inhibition was observed for the MaNR hybrid spheroids at this 5:1 ratio, even at the highest irradiance investigated (28 W/cm2). Although AuNR were taken up by Ma in larger numbers than AuNS, MaNS were shown to have greater PTT efficacy compared to MaNR for equivalent numbers of loaded Ma.
关键词： photothermal therapy,glioma,murine macrophages,gold-silica nanoshells,gold nanorods
更新于2025-09-09 09:28:46
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Thermal Reshaping Dynamics of Gold Nanorods: Influence of Size, Shape, and Local Environment
摘要： The thermal reshaping of gold nanorods in a polymer matrix is an important phenomenon for many potential applications. However, a fundamental understanding of the various mechanisms that govern the nanorod reshaping dynamics is still lacking. Here we provide evidence for a phenomenological model of the gold nanorod shape transformation based on the measurements and detailed analysis of the time-resolved thermal reshaping for a variety of gold nanorods having different geometries (aspect ratio, volume, diameter) in a crosslinked epoxy matrix at application relevant temperatures (120 ? 220 ?C). Our analysis suggests that a) the nanorod reshaping dynamics consist of two temporal regimes that are governed by different phenomena, and b) the ultimate amount of reshaping at a given temperature depends strongly on the initial particle geometry and the mechanical stiffness of its surroundings. At short times the shape transformation is dominated by a curvature-induced surface diffusion process in which the activation energy for diffusion depends on curvature. At long times, however, the surrounding environment plays a key role in slowing the diffusion and stabilizing the nanorod shape. We show that the long time behavior can be well described using a modified surface diffusion model that takes into account the slowing of atomic diffusivity as a result of external forces arising from mechanical constraints. The ability to tune both the final shape and the reshaping dynamics in nanocomposites opens up new possibilities in tailoring the optical properties of these materials.
关键词： Polymer Nanocomposites,Surface Diffusion,Temperature Sensing,Plasmonics,Thermal Reshaping,Gold Nanorods
更新于2025-09-09 09:28:46
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Synthesis of Gold Nanorods Using Poly(vinylpyrrolidone) of Different Molecular Weights as an Additive
摘要： The use of poly(vinylpyrrolidone) (PVP) of different molecular weights (5-360 kDa) during the synthesis of gold nanorods (AuNRs) via seedless and seed-mediated approaches is reported. For both syntheses, the LSPR band can be tuned from 700 to 1050 nm by modifying the molecular weight of PVP in a time dependent addition of polymer. Moreover, the growth of AuNRs in 100 mM cetyltrimethylammonium bromide (CTAB) is accelerated as the molecular weight of PVP increases from 5 to 360 kDa for the seedless approach. In the case of AuNRs synthesized by the seed-mediated approach, the aspect ratio decreases from 7.41 to 3.72 as the molecular weight of PVP increases to 55 kDa. For both protocols, high molecular weight of PVP reduces the shape yield despite of producing smaller AuNRs. Therefore, the incorporation of small amounts of PVP during the growth stage can be utilized for the preparation of anisotropic nanostructures to tune their optical properties and improve their shape yield.
关键词： Hydroquinone,Poly(vinylpyrrolidone),Seedless synthesis,Seed-mediated synthesis,Gold nanorods
更新于2025-09-09 09:28:46
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In vivo and in vitro demonstration of gold nanorod aided photothermal pre-softening of B16F10 melanoma for efficient chemotherapy using Doxorubicin loaded Graphene Oxide
摘要： A combined photothermal therapy (PTT), and chemotherapy (chemo) was performed in vitro on B16F10 melanoma cells, and in vivo using melanoma bearing C57BL/6 mice. 785 nm (100 mW) irradiated gold nanorods (AuNRs) was used as the PT agent, and electrostatically conjugated Doxorubicin (Dox) to a nanocarrier graphene oxide (GO) worked as the chemotherapeutic. Selection of dosage was optimized from the individual viability studies, and finally a combined therapeutic (AuNR (100 ppm), GO (125, and 250 ppm), Dox (0.0058, and 0.00058 ppm)), was delivered in vitro. PTT, followed by chemo, sequentially, resulted in <10 % viability, whereas simultaneous PTT with chemo resulted in a viability of ~40 % for the melanoma cells. Flow cytometry indicated optical inhomogeneity in the cells that internalized GO, and AuNR, however, the Dox amount was identical within the cells treated with or without PTT. Confocal microscopy revealed that GO-Dox was internalized, and Dox was distributed uniformly within the cells irrespective of the treatment protocol. In vivo results in melanoma bearing C57BL/6 mice resembled the in vitro data closely. The tumor growth inhibition index was highest at 0.78 for the group receiving sequential treatment, followed by 0.61 for those receiving simultaneous treatment, where the control group had a score of 0. For the sequential treatment, pre-softening of the cells with PTT, followed by the chemo resulted in significantly improved toxicity of the treatment, whereas simultaneous PTT, with chemo results were dominated by the Dox alone.
关键词： Nanomedicine,Graphene Oxide,Photothermal therapy,Melanoma,Drug delivery,Gold Nanorods
更新于2025-09-04 15:30:14
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Direct formation of gold nanorods on surfaces using polymer-immobilised gold seeds
摘要： Herein, we present the formation of gold nanorods (GNRs) on novel gold–poly(methyl methacrylate) (Au–PMMA) nanocomposite substrates with unprecedented growth control through the polymer molecular weight (Mw) and gold-salt-to-polymer weight ratio. For the first time, GNRs have been produced by seed-mediated direct growth on surfaces that were pre-coated with polymer-immobilised gold seeds. A Au–PMMA nanocomposite formed by UV photoreduction has been used as the gold seed. The influence of polymer Mw and gold concentration on the formation of GNRs has been investigated and discussed. The polymer nanocomposite formed with a lower Mw PMMA and 20 wt % gold salt provides a suitable medium for growing well-dispersed GNRs. In this sample, the average dimension of produced GNRs is 200 nm in length with aspect ratios up to 10 and a distribution of GNRs to nanoparticles of nearly 22%. Suitable characterization techniques such as AFM and SEM have been used to support concept of the proposed growth method.
关键词： direct surface growth,gold nanorods,nanocomposites,atomic force microscopy (AFM),poly(methyl methacrylate) (PMMA)
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE International Conference on Manipulation, Manufacturing and Measurement on the Nanoscale (3M-NANO) - Hangzhou, China (2018.8.13-2018.8.17)] 2018 IEEE International Conference on Manipulation, Manufacturing and Measurement on the Nanoscale (3M-NANO) - Precisely Lateral Alignment of Gold Nanorods Array via Hydrophilic-Hydrophobic Pattern
摘要： A simple strategy which combines the controlled solvent evaporation and hydrophilic-hydrophobic pattern to allow assembling gold nanorods (GNRs) on a flat substrate with arbitrary shapes in this work. Soft polydimethylsiloxane (PDMS) template as a pattern transfer stamp were utilized and transferred the structures onto the substrate successfully. By tuning the structures and sizes of templates, oriented large area lateral aligned GNRs arrays were fabricated as expected. Scan electron microscopy (SEM) images revealed that GNRs had been precisely placed as expected and the assembly is uniform.
关键词： hydrophilic-hydrophobic pattern,gold nanorods,self-assembly,solvent evaporation,micro-array
更新于2025-09-04 15:30:14