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Controlled Gold Nanoparticle Placement into Patterned Polydimethylsiloxane Thin Films via Directed Self-Assembly
摘要： An economically scalable and reproducible method to assemble nanoparticles (NPs) into ordered arrays with high fidelity remains a fundamental roadblock. Methods like directed self-assembly have shown the highest promise resulting in >85% density of NP-filled prepatterned polymer cavities. This work refines directed self-assembly by controlling the evaporation rate, substrate velocity (deposition rate), and NP diameter resulting in reproducible fabrication of ordered arrays with areas >2 mm × 2 mm and ~100% density of filled cavities. Measured optical spectra showed a blueshift in the localized surface plasmon resonance (LSPR) and surface lattice resonance (SLR) peaks with increasing NP density for both 100 and 150 nm gold (Au) NPs. Discrete dipole approximation (DDA), coupled dipole approximation (CDA), rapid semi-analytical CDA (rsa-CDA), and Mie theory simulations closely matched extinction per nanoparticle (extinction/NP) calculations for measured extinction spectra. An ordered array containing 150 nm AuNPs was used for comparison with rsa-CDA estimates using both polydimethylsiloxane (PDMS) and glass refractive indices (RI) resulting in peak location estimates within 1.7% and comparable relative increases in peak heights. Both the measured and simulated SLR peak heights were shown to significantly increase when the array was on glass as opposed to within PDMS.
关键词： directed self-assembly,extinction spectra,gold nanoparticles,surface lattice resonance,localized surface plasmon resonance
更新于2025-09-12 10:27:22
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Boosting the efficiency of dye-sensitized TiO2 solar cells using plasmonic gold nanoparticles
摘要： In this work, the focus is on the modification of titanium dioxide (TiO2) photoanode in dye-sensitized solar cells (DSSCs) by mixing the TiO2 with plasmonic gold (Au) nanoparticles with the aim to enhance the performance. Different concentrations of Au nanoparticles were incorporated into TiO2 and their J-V characteristics have been taken under white light intensity of 100 mW cm-2 to obtain the optimum concentration. DSSC made from commercial ruthenium based dye (N3) with TiO2 containing 40 μL Au photoanode and liquid electrolyte (iodolyte Z-50) exhibited the Jsc of 17.52 mA cm-2, Voc of 0.62 V, FF of 0.64 and efficiency, η of 6.97 %. The photovoltaic parameters in terms of Jsc and η have showed improvement by 83% and 68%, respectively. The enhanced performance is due to more photocurrent have been generated as a result from the plasmonic effects of Au nanoparticles that improved the light absorption and scattering.
关键词： Plasmonic,Dye-sensitized solar cells,Gold nanoparticles
更新于2025-09-12 10:27:22
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Rapid and Digital Detection of Inflammatory Biomarkers Enabled by a Novel Portable Nanoplasmonic Imager
摘要： New point-of-care diagnostic devices are urgently needed for rapid and accurate diagnosis, particularly in the management of life-threatening infections and sepsis, where immediate treatment is key. Sepsis is a critical condition caused by systemic response to infection, with chances of survival drastically decreasing every hour. A novel portable biosensor based on nanoparticle-enhanced digital plasmonic imaging is reported for rapid and sensitive detection of two sepsis-related inflammatory biomarkers, procalcitonin (PCT) and C-reactive protein (CRP) directly from blood serum. The device achieves outstanding limit of detection of 21.3 pg mL?1 for PCT and 36 pg mL?1 for CRP, and dynamic range of at least three orders of magnitude. The portable device is deployed at Vall d’Hebron University Hospital in Spain and tested with a wide range of patient samples with sepsis, noninfectious systemic inflammatory response syndrome (SIRS), and healthy subjects. The results are validated against ultimate clinical diagnosis and currently used immunoassays, and show that the device provides accurate and robust performance equivalent to gold-standard laboratory tests. Importantly, the plasmonic imager can enable identification of PCT levels typical of sepsis and SIRS patients in less than 15 min. The compact and low-cost device is a promising solution for assisting rapid and accurate on-site sepsis diagnosis.
关键词： imaging biosensors,nanoplasmonics,point-of-care diagnostics,sepsis,gold nanoparticles
更新于2025-09-12 10:27:22
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Highly Transparent and Surface-Plasmon-Enhanced Visible-Photodetector Based on Zinc Oxide Thin-Film Transistors with Heterojunction Structure
摘要： Highly transparent zinc oxide (ZnO)-based thin-film transistors (TFTs) with gold nanoparticles (AuNPs) capable of detecting visible light were fabricated through spray pyrolysis on a fluorine-doped tin oxide substrate. The spray-deposited channel layer of ZnO had a thickness of approximately 15 nm, and the thickness exhibited a linear increase with an increasing number of sprays. Furthermore, the ZnO thin-film exhibited a markedly smoother channel layer with a significantly lower surface roughness of 1.84 nm when the substrate was 20 cm from the spray nozzle compared with when it was 10 cm away. Finally, a ZnO and Au-NP heterojunction nanohybrid structure using plasmonic energy detection as an electrical signal, constitutes an ideal combination for a visible-light photodetector. The ZnO-based TFTs convert localized surface plasmon energy into an electrical signal, thereby extending the wide band-gap of materials used for photodetectors to achieve visible-light wavelength detection. The photo-transistors demonstrate an elevated on-current with an increase of the AuNP density in the concentration of 1.26, 12.6, and 126 pM and reach values of 3.75, 5.18, and 9.79 × 10?7 A with applied gate and drain voltages. Moreover, the threshold voltage (Vth) also drifts to negative values as the AuNP density increases.
关键词： gold-nanoparticles,phototransistors,plasmonic energy detection,spray pyrolysis,zinc oxide-based thin-film transistors
更新于2025-09-12 10:27:22
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Photo-induced generation of size controlled Au nanoparticles on pure siliceous ordered mesoporous silica for catalytic applications
摘要： A versatile in situ photochemical reduction approach was used to generate a composite of gold nanoparticles and pure siliceous SBA-15 silica support with regular mesopores. The mesoporous silica support was first synthesized and, after calcination, was suspended in a solution of gold bromide (EtOH or H2O) containing a free radical generator activated by UV irradiation and used for the photochemical reduction of gold precursor. The influence of gold precursor concentration, light intensity and nature of the solvents on the formation and properties of gold nanoparticles (size, dispersion, stability) on the mesoporous SBA-15 support have been studied with the aim of optimizing the dispersion of the gold nanoparticles in the mesoporous network and their chemical stability. The catalytic activity of the resulting AuNPs@SBA-15 nanocomposite was successfully evaluated for the oxidation of benzyl alcohol reaction in liquid-phase.
关键词： Benzyl alcohol,Photoreduction,Gold nanoparticles,Mesoporous silica,SBA-15,Oxidation
更新于2025-09-12 10:27:22
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Nitrone-Modified Gold Nanoparticles: Synthesis, Characterization, and Their Potential as <sup>18</sup> F-Labeled Positron Emission Tomography Probes via I-SPANC
摘要： A novel bioorthogonal gold nanoparticle (AuNP) template displaying interfacial nitrone functional groups for bioorthogonal interfacial strain-promoted alkyne?nitrone cycloaddition reactions has been synthesized. These nitrone?AuNPs were characterized in detail using 1H nuclear magnetic resonance spectroscopy, transmission electron microscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy, and a nanoparticle raw formula was calculated. The ability to control the conjugation of molecules of interest at the molecular level onto the nitrone?AuNP template allowed us to create a novel methodology for the synthesis of AuNP-based radiolabeled probes.
关键词： bioorthogonal chemistry,radiolabeled probes,PET imaging,nitrone,gold nanoparticles
更新于2025-09-12 10:27:22
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Laser and thermal dewetting of gold layer onto graphene paper for non-enzymatic electrochemical detection of glucose and fructose
摘要： Electrochemical non-enzymatic detections of glucose and fructose were based on gold nanoparticles (AuNPs) onto graphene paper. Electrodes based on AuNPs have been obtained inducing dewetting, by thermal (furnace) or by laser, of sputter deposited 8 nm-thick Au layer onto graphene paper. The electrodes were characterized by Scanning Electron Microscopy, Micro Raman Spectroscopy, X-ray Diffraction, Rutherford back-scattering Spectroscopy and Cyclic Voltammetry. The main difference exhibited by thermal and laser dewetting processes lies in the size and shape of the resulting gold nanoparticles. Laser dewetting originates smaller particles than that obtained by thermal dewetting. The particles are almost spherical and mainly localized onto graphene nanoplatelets. The size of AuNPs is in the ranges 10–150 nm. Electrodes obtained by thermal process present gold nanostructures characterized by faceted AuNPs. Typical sizes are in the range of 20–40 and 200–400 nm. The electrocatalytic activity toward glucose and fructose oxidation in alkaline phosphate buffer solution are presented and discussed. Glucose was detected at a potential of 0.17 V (laser dewetting) or 0.19 V (thermal dewetting) vs SCE, which corresponds to the intense peak of two electrons oxidation. Fructose was detected at potential of 0.4 V vs SCE. Sensitivity up to 1240 μA mM?1 cm?2 for glucose detection was obtained. The resulting analytical performances for glucose and fructose detection are very promising since comparable to the actual state of art for nanostructured gold electrodes which are, however, produced by complex multi-steps wet processes and/or enzymes.
关键词： Glucose,Gold nanoparticles,Graphene paper,Fructose electrochemical detection
更新于2025-09-12 10:27:22
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99mTc-Labeled Polyethyleneimine-Entrapped Gold Nanoparticles with pH-Responsive Charge Conversion Property for Enhanced Dual Mode SPECT/CT Imaging of Cancer Cells
摘要： Development of tumor dual mode contrast agent is still a great challenge due to the relative low accumulation at tumor site, which result in the poor imaging efficiency. In this study, we constructed functional technetium-99m (99mTc) labeled polyethyleneimine (PEI)-entrapped gold nanoparticles (Au PENs) with pH-responsive charge conversion property for enhanced single photon emission computed tomography (SPECT)/computed tomography (CT) dual mode imaging of cancer cells. PEI with amine functional groups (PEI.NH2) was successively modified with monomethyl ether and carboxyl functionalized polyethylene glycol (mPEG-COOH), maleimide and succinimidyl valerate functionalized PEG (MAL-PEG-SVA), diethylenetriaminepentaacetic dianhydride (DTPA), and fluorescein isothiocyanate (FI), and used to entrapped gold nanoparticles inside, followed by conjugation with the alkoxyphenyl acylsulfonamide (APAS) through the PEG maleimide, acetylation of the PEI leftover surface amines and 99mTc labeling. The created nanosystem with the mean Au core diameter of 3.3 nm and with a narrow size distribution displays an excellent colloidal stability and desired cytocompatibility in the investigated Au concentration range. Due to the fact that the attached APAS moieties are responsive to pH, the functionalized Au PENs with a neutral surface charge can switch to be positively charged under slightly acidic pH condition, which could improve the cellular uptake by cancer cells. With these properties, the developed functionalized Au PENs could achieve enhanced dual mode SPECT/CT imaging of cancer cells in vitro. The constructed PEI-based nanodevices may be adopted as an excellent dual mode contrast agent for SPECT/CT imaging of cancer cells of different types.
关键词： technetium-99m,gold nanoparticles,SPECT imaging,CT imaging,pH-responsive charge conversion,polyethyleneimine
更新于2025-09-12 10:27:22
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Quercetin encapsulated biodegradable plasmonic nanoparticles for photothermal therapy of hepatocellular carcinoma cells
摘要： Photothermal therapy (PTT) is emerging as an effective treatment modality for cancer due to its non-invasive nature. However, the pro-inflammatory necrotic cell death during PTT limits its successful clinical application. Here, we have developed quercetin (QE) loaded biodegradable plasmonic nanoparticles that can specifically induce apoptosis in cancer cells after PTT. We have synthesized gold-coated liposome (LiposAu) and QE loaded gold-coated liposome (QE-LiposAu) nanoparticles by in situ reduction of chloroauric acid with ascorbic acid in the presence of bare liposomes (Lipos) or QE loaded liposomes (QE-Lipos), respectively. The gold coating was confirmed by transmission electron microscopic analysis, dynamic light scattering, and zeta potential measurements. LiposAu and QE-LiposAu nanoparticles showed a similar level of temperature rise upon 750 nm near-infrared (NIR) laser (650 mW, 3 W cm-2) irradiation. The photothermal conversion efficiency of QE-LiposAu nanoparticles was determined to be ~75%. The efficacy of PTT was found to be dependent on the internalization efficiency of LiposAu nanoparticles in cancer cells. Importantly, QE-LiposAu nanoparticles showed increased PTT efficacy over LiposAu nanoparticles in hepatocellular carcinoma cells (Huh-7). Moreover, QE-LiposAu nanoparticles induced apoptosis-mediated cell death after the PTT, and the extent of apoptosis was significantly higher than the LiposAu nanoparticles in Huh-7 cells. Further, QE-LiposAu nanoparticles-mediated PTT depolymerized microtubules network, suppressed Hsp70 expression, and caused DNA damage. QE-LiposAu nanoparticles were also found to be hemocompatible. The results together suggested that biodegradable QE-LiposAu nanoparticles are promising photothermal agents for cancer therapy.
关键词： heat shock protein,liposome,microtubule,apoptosis,gold nanoparticles,DNA damage,Photothermal therapy
更新于2025-09-12 10:27:22
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Development of Plasmonic Chitosan-Squarate Hydrogels via Bio-Inspired Nanoparticle Growth
摘要： We report on the bio-inspired growth of gold nanoparticles (GNPs) in biocompatible hydrogels to develop plasmonic hybrid materials. The new hydrogel (CS-Sq) is prepared from chitosan and diethylsquarate and is formed via non-covalent interactions rising between the in-situ formed ionic squaric acid derivatives and chitosan. Interestingly, when the hydrogel is prepared in the presence of HAuCl4, GNPs with controlled sizes between 15 and 50 nm are obtained which are homogeneously distributed within the plasmonic hydrogels (GNPs-CS-Sq). We found that the supramolecular nature and the composition of the CS-Sq hydrogels are key for the GNPs growth process where the squaric derivatives act as reducing agents and the chitosan hydrogel network provides nucleation points and supports the GNPs. Accordingly, the hydrogel acts as a bio-inspired reactor and permits to gain certain control on the GNPs size by adjusting the concentration of chitosan and HAuCl4. Besides the intrinsic and tunable plasmonic properties of the GNPs-CS-Sq hydrogels, it was found that the gels could be useful as heterogeneous catalysts for organic reactions. Furthermore, cell viability studies indicate that the new hydrogels exhibit suitable biocompatibility. Thus, the proposed method for obtaining GNPs-CS-Sq hydrogels has the potential to be applied for the development of a wide variety of other hybrid chitosan materials useful for catalysis, biosensing, cell culture, tissue engineering, and drug delivery applications.
关键词： Chitosan,Hybrid Materials,Hydrogels,Squaric Acid,Gold Nanoparticles
更新于2025-09-12 10:27:22