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- 实验方案
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Reduced Graphene Oxide Functionalized with Gold Nanostar Nanocomposites for Synergistically Killing Bacteria through Intrinsic Antimicrobial Activity and Photothermal Ablation
摘要： The exploration of multifunctional photothermal agent is important for antibacterial photothermal lysis, which has emerged as an effective approach to address the problem of pathogenic bacteria infection irrespective of the drug resistant effect. In the present work, a 2D reduced graphene oxide supported Au nanostar nanocomposite (rGO/AuNS) was prepared by the seed mediated growth method for synergistically killing multidrug resistant bacteria. Owing to the prickly and sharp-edge nanostructure, the rGO/AuNS displayed superior antibacterial activity probably due to the damaging of the cell walls or membranes. The cell viability of MRSA was as low as 32% when the MRSA were incubated with rGO/AuNS for 180 min in the absence of light. The 2D structure of the rGO/AuNS facilitated the strong binding affinity towards bacteria. Upon the 808 nm NIR laser irradiation, significant enhancement in bactericidal efficiency (complete death) was obtained due to the localized hyperthermal effect of rGO/AuNS. Moreover, the RGO/AuNS displayed promising biocompatibility. It indicates that the rGO/AuNS can be an alternative and effective dual functional photothermal agent for synergistically killing the multidrug resistant bacteria.
关键词： Reduced Graphene Oxide,Multidrug-resistant bacteria,Antibacterial photothermal lysis,Gold nanostars,Prickly nanostructure
更新于2025-09-23 15:22:29
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Intercellular Trafficking of Gold Nanostars in Uveal Melanoma Cells for Plasmonic Photothermal Therapy
摘要： Efficient plasmonic photothermal therapies (PPTTs) using non-harmful pulse laser irradiation at the near-infrared (NIR) are a highly sought goal in nanomedicine. These therapies rely on the use of plasmonic nanostructures to kill cancer cells while minimizing the applied laser power density. Cancer cells have an unsettled capacity to uptake, retain, release, and re-uptake gold nanoparticles, thus offering enormous versatility for research. In this work, we have studied such cell capabilities for nanoparticle trafficking and its impact on the effect of photothermal treatments. As our model system, we chose uveal (eye) melanoma cells, since laser-assisted eye surgery is routinely used to treat glaucoma and cataracts, or vision correction in refractive surgery. As nanostructure, we selected gold nanostars (Au NSs) due to their high photothermal efficiency at the near-infrared (NIR) region of the electromagnetic spectrum. We first investigated the photothermal effect on the basis of the dilution of Au NSs induced by cell division. Using this approach, we obtained high PPTT efficiency after several cell division cycles at an initial low Au NS concentration (pM regime). Subsequently, we evaluated the photothermal effect on account of cell division upon mixing Au NS-loaded and non-loaded cells. Upon such mixing, we observed trafficking of Au NSs between loaded and non-loaded cells, thus achieving effective PPTT after several division cycles under low irradiation conditions (below the maximum permissible exposure threshold of skin). Our study reveals the ability of uveal melanoma cells to release and re-uptake Au NSs that maintain their plasmonic photothermal properties throughout several cell division cycles and re-uptake. This approach may be readily extrapolated to real tissue and even to treat in situ the eye tumor itself. We believe that our method can potentially be used as co-therapy to disperse plasmonic gold nanostructures across affected tissues, thus increasing the effectiveness of classic PPTT.
关键词： nanoparticle endocytosis,femtosecond pulse laser,nanoparticle exocytosis,gold nanostars,plasmonic photothermal therapy
更新于2025-09-23 15:21:01
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Plasmonic nanostar photocathodes for optically-controlled directional currents
摘要： Plasmonic nanocathodes offer unique opportunities for optically driving, switching, and steering femtosecond photocurrents in nanoelectronic devices and pulsed electron sources. However, angular photocurrent distributions in nanoplasmonic systems remain poorly understood and are therefore difficult to anticipate and control. Here, we provide a direct momentum-space characterization of multiphoton photoemission from plasmonic gold nanostars and demonstrate all-optical control over these currents. Versatile angular control is achieved by selectively exciting different tips on single nanostars via laser frequency or linear polarization, thereby rotating the tip-aligned directional photoemission as observed with angle-resolved 2D velocity mapping and 3D reconstruction. Classical plasmonic field simulations combined with quantum photoemission theory elucidate the role of surface-mediated nonlinear excitation for plasmonic field enhancements highly concentrated at the sharp tips (Rtip = 3.4 nm). We thus establish a simple mechanism for femtosecond spatiotemporal current control in designer nanosystems.
关键词： Plasmonic nanostars,gold nanostars,photocathodes,optically-controlled directional currents,multiphoton photoemission
更新于2025-09-23 15:19:57
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Thermoplasmonic Maskless Lithography on Upconverting Nanocomposites Assisted by Gold Nanostars
摘要： Photothermal effects in plasmonic nanoparticles can be used to locally modify temperature-sensitive materials. Polylactic acid (PLA) is a thermoplastic biodegradable polymer with a glass transition temperature around 60 ?C that has been popularized as a feedstock material for 3D printing. Here, we extend its use to produce thin PLA films that can be modified at the microscopic level when covered with gold nanostars (AuNSs). The heat dissipation generated when exciting the plasmon resonance of AuNSs, under exposure to 976 nm focused laser light, produce an increase in the local temperature of more than 100 ?C. When the temperature surpasses the glass transition of the base PLA layer, AuNSs get attached to the polymer surface. The following dissolution of the unexposed material in acetone bath permits the precise control of the engraving process at the microscale. Furthermore, Er3+ doped upconverting nanoparticles embedded into the PLA layer can act as optical nanothermometers to probe the local temperature, simultaneously allowing the visualization of the laser spot. A computer numerical control (CNC) system was developed to drive the laser writing beam and transfer 2D patterns, opening up the thermoplasmonic maskless lithography technique. Suitable for rigid and flexible substrates coated with PLA, the methods and materials developed here were applied to produce patterned substrates for surface enhanced Raman spectroscopy, and luminescent optical encoding for anti-counterfeiting technologies.
关键词： photothermal nanoparticles,gold nanostars,optical thermometry,thermoplasmonics,maskless lithography,upconversion nanoparticles
更新于2025-09-16 10:30:52
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Plasmonic gold nanostar-mediated photothermal immunotherapy for brain tumor ablation and immunologic memory
摘要： Brain tumors present unique therapeutic challenges and they include glioblastoma (GBM) and metastases from cancers of other organs. Current treatment options are limited and include surgical resection, radiation therapy, laser interstitial thermal therapy and chemotherapy. Although much research has been done on the development of immune-based treatment platforms, only limited success has been demonstrated. Herein, we demonstrate a novel treatment of GBM through the use of plasmonic gold nanostars (GNS) as photothermal inducers for synergistic immuno photothermal nanotherapy (SYMPHONY), which combines treatments using gold nanostar and laser-induced photothermal therapy with checkpoint blockade immunotherapy. In the treatment of a murine flank tumor model with the CT-2A glioma cell line, SYMPHONY demonstrated the capability of producing long-term survivors that rejects rechallenge with cancer cells, heralding the successful emergence of immunologic memory. This study is the first to investigate the use of this novel therapy for the treatment of GBM in a murine model.
关键词： gold nanostars,cancer immunology,immunotherapy,cancer vaccines,photothermal therapy,glioblastoma
更新于2025-09-12 10:27:22
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The synthesis of Ag-coated tetrapod gold nanostars and the improvement of surface-enhanced Raman scattering
摘要： In this work, the novel tetrapod gold nanostars with four specific numbers of sharp tips were synthesized with good uniformity, high yield and chemical stability. The size of tetrapod gold nanostars has been increased effectively by increasing the amount of HAuCl4 or DEA added to the reaction solution, and the corresponding in-plane localized surface plasmon resonance (LSPR) band can shift from 700 to 1100 nm. In order to combine the advantages of different metals, the Ag-coated tetrapod gold nanostars were prepared with different Ag coating thicknesses by increasing the volume of AgNO3. With the increase of Ag coating thickness, the morphology of the nanoparticles has changed from gold nanostars with four sharp tips to bimetallic cuboids with four sharp tips and finally to core-shell cuboids completely. The surface-enhanced Raman scattering (SERS) activity of Ag-coated tetrapod gold nanostars has also been improved with the different Ag coating thicknesses. Combined the tip effect and the enhancement effect of Ag, the SERS activity has the strongest enhancement when the four sharp tips of tetrapod gold nanostars are not completely coated by the Ag layer but still exposed to the outsides. For tetrapod gold nanostars with larger size to grow Ag-coated tetrapod gold nanostars, the bimetallic cuboids with four sharp tips nanostructure have the biggest SERS enhancement factor (EF) of 1.73×106 for Rhodamine 6G (R6G), making it an ideal candidate in SERS-based sensing application.
关键词： R6G,Au-Ag bimetallic cuboids,SERS,Tetrapod gold nanostars,Silver coating
更新于2025-09-10 09:29:36
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Intelligent Photosensitive Mesenchymal Stem Cells and Cell-Derived Microvesicles for Photothermal Therapy of Prostate Cancer
摘要： Targeted delivery of nanomedicines into the tumor site and improving the intratumoral distribution remain challenging in cancer treatment. Here, we report an effective transportation system utilizing both of mesenchymal stem cells (MSCs) and their secreted microvesicles containing assembled gold nanostars (GNS) for targeted photothermal therapy of prostate cancer. The stem cells act as a cell carrier to actively load and assemble GNS into the lysosomes. Accumulation of GNS in the lysosomes facilitates the close interaction of nanoparticles, which could result in a 20 nm red-shift of surface plasmon resonance of GNS with a broad absorption in the near infrared region. Moreover, the MSCs can behave like an engineering factory to pack and release the GNS clusters into microvesicles. The secretion of GNS can be stimulated via light irradiation, providing an external trigger-assisted approach to encapsulate nanoparticles into cell derived microvesicles. In vivo studies demonstrate that GNS-loaded MSCs have an extensive intratumoral distribution, as monitored via photoacoustic imaging, and efficient antitumor effect under light exposure in a prostate-cancer subcutaneous model by intratumoral and intravenous injection. Our work presents a light-responsive transportation approach for GNS in combination of MSCs and their extracellular microvesicles and holds the promise as an effective strategy for targeted cancer therapy including prostate cancer.
关键词： mesenchymal stem cells,photothermal therapy,targeted transportation,microvesicles,gold nanostars
更新于2025-09-04 15:30:14
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SERS-Based Quantification of PSMA in Tissue Microarrays Allows Effective Stratification of Patients with Prostate Cancer
摘要： Prostate specific membrane antigen (PSMA), a type II membrane protein, is an attractive biomarker that has been validated clinically for the diagnosis of prostate cancer. In this study, we developed surface-enhanced Raman scattering (SERS) nanoprobes for PSMA detection and quantification at the single-cell level on prostate cancer cells. The cells were targeted employing SERS nanoprobes that consisted of gold nanostars functionalized with PSMA aptamer molecules. We were able to quantify picomolar concentrations of soluble PSMA protein and used the resulting calibration curve to estimate the expression of PSMA on the surface of the prostate cancer cell, LNCaP, at the single-cell level. Importantly, we employed these SERS tags to stratify prostate cancer patients by assessing PSMA expression in tissues contained in a prostate tissue microarray. The stratification results clearly correlated PSMA expression to recommended therapy groups, rendering the described method as an effective tool to aid in designing personalized therapeutic protocols. Benchmarking detection sensitivity against immunofluorescence staining and comparing stratification results obtained with the two methods allowed us to validate our novel approach against standard practices. On the basis of these results, we confirm the validity of PSMA as an effective biomarker for prostate cancer patient evaluation and propose SERS-based diagnostic techniques as integrative methods for the assessment of disease stage and the identification of effective therapeutic protocols.
关键词： aptamer,tissue microarray,surface-enhanced Raman scattering,PSMA,Prostate specific membrane antigen,SERS,nanoprobes,prostate cancer,biomarker,gold nanostars
更新于2025-09-04 15:30:14
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Plasmon Tunability of Gold Nanostars at the Tip Apexes
摘要： Herein, we present an optimized bottom-up approach to fabricate homogeneous Au nanostars with plasmon resonances fully tunable between the red and the infrared. The synthetic method relies on the kinetic control of the reaction upon optimization of the reactant concentrations (i.e., gold seeds, reducing agent, and gold salt). Optical enhancing properties of the obtained materials are demonstrated by using SERS with visible and infrared lasers.
关键词： SERS,plasmon tunability,gold nanostars,visible and infrared lasers
更新于2025-09-04 15:30:14
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Theoretical study on surface plasmon properties of gold nanostars
摘要： With the rapid development of nanotechnology, the surface plasmon properties of metal nanostructures have become the focus of research. In this paper, a multi-tip gold nanostars (GNSs) structure is designed theoretically, and its surface plasmon properties are simulated by using the finite element method (FEM), which is practical and versatile. Compared with the traditional spherical and triangular plate particles, the results show that the tip structure of the GNSs has a stronger hot spots effect, resulting in greater local field enhancement properties. The relationship between the structure parameters of GNSs and their resonance peaks was also studied. The results indicate that the resonance peaks of GNSs depend strongly on the size, spacing between two GNSs, quantity and refractive index of the GNSs.
关键词： surface plasmon,finite element method,resonance peaks,gold nanostars,local field enhancement
更新于2025-09-04 15:30:14