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Tailoring optical cross sections of gold nanorods at a target plasmonic resonance wavelength using bromosalicylic acid
摘要： In many applications, the optical cross sections of gold nanorods (AuNRs) are required to be tailored at a fixed target longitudinal surface plasmon resonance (LSPR) wavelength depending on the excitation source and the photodetector. In this work, we demonstrate the fine tailoring of optical cross sections of AuNRs at a fixed target resonance wavelength, on the basis of AuNR overgrowth using a binary surfactant mixture consisting of 5-bromosalicylic acid (BSA) and cetyltrimethylammonium bromide (CTAB). A systematic study was performed on the sum effects of the BSA concentration and the volume of the growth solution, which gives a formula for quantitative instructions. Based on the formula, we gave examples for the successful synthesis of AuNRs with different optical cross sections at target LSPR wavelengths. From simulation, a nonlinear relationship was further derived to understand the relationship between the aspect ratio and the width of the AuNRs at a target LSPR wavelength for the dimension design of AuNRs. The ratio of optical against physical cross sections was calculated and plotted as a function of the width. The results clearly indicate that AuNRs with a width of 30 nm possess the highest efficiency in terms of optical per physical cross section. Our study provides reliable methods for the synthesis, as well as guidelines for the dimension design of AuNRs, for use in a variety of applications.
关键词： 5-bromosalicylic acid,gold nanorods,optical cross sections,cetyltrimethylammonium bromide,surface plasmon resonance
更新于2025-11-19 16:56:42
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In-Situ covalent synthesis of gold nanorods on GO surface as ultrasensitive Raman probe
摘要： In this paper, using thiolated graphene oxide (GO‐O‐SH) as substrate, gold nanorods (AuNRs) covalently linked to the GO surface by in‐situ seed growth method were first reported. The as‐prepared composites were characterized by UV–vis spectrum, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT‐IR). Experimental results indicated that the introduction of short flexible organic chain between GO and AuNRs contributed to the homogenous synthesis of gold rods, and uniform gold nanorods with aspect ratio within 3~8 were covalently linked to the surface of GO with high stability and yield. The strategy represented an outstanding improvement in comparison to the traditional route for fabricating the two GO@AuNRs composites. Furthermore, based on coupling of nanomaterials, the composites could act as high sensitive Raman probe with limit of detection (LOD) reaching 1 × 10?12 M.
关键词： covalent synthesis,Raman probe,graphene oxide (GO),gold nanorods
更新于2025-09-23 15:23:52
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Optical limiting property of gold nanorods/ormosil gel glass composites
摘要： Sol–gel derived ormosil gel glass can act as matrix for different functional molecules or nanomaterials due to its many advantages. Gold and silver colloidal nanoparticles have great application potential in nonlinear optical field due to their ultrafast optical response. In this letter, the nanocomposites of gold nanorods and ormosil gel glass were prepared by a solvent-assisted dispersing process and characterized by UV–vis spectra, TEM, XRD and optical limiting measurement. The results showed that these gold/ormosil nanocomposites could preserve optical limiting property of gold nanorods and had enhanced thermostability due to thermostable silica matrix. Such nanocomposite material of metal-doped gel glass matrix could be considered as a promising candidate for optical limiter against tunable laser.
关键词： Nanocomposites,Optical limiting,Ormosil gel glass,Thermostability,Gold nanorods
更新于2025-09-23 15:23:52
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A personalized and long-acting local therapeutic platform combining photothermal therapy and chemotherapy for the treatment of multidrug-resistant colon tumor
摘要： Background: Local photothermal therapy (PTT) provides an easily applicable, noninvasive adjunctive therapy for colorectal cancer (CRC), especially when multidrug resistance (MDR) occurs. However, using PTT alone does not result in complete tumor ablation in many cases, thus resulting in tumor recurrence and metastasis. Materials and methods: In this study, we aim to develop a personalized local therapeutic platform combining PTT with long-acting chemotherapy for the treatment of MDR CRC. The platform consists of polyethylene glycol (PEG)-coated gold nanorods (PEG-GNRs) and d-alpha-tocopheryl PEG 1000 succinate (TPGS)-coated paclitaxel (PTX) nanocrystals (TPGS-PTX NC), followed by the incorporation into an in situ hydrogel (gel) system (GNRs-TPGS-PTX NC-gel) before injection. After administration, PEG-GNRs can exert quick and efficient local photothermal response under near-infrared laser irradiation to shrink tumor; TPGS-PTX NC then provides a long-acting chemotherapy due to the sustained release of PTX along with the P-glycoprotein inhibitor TPGS to reverse the drug resistance. Results: The cytotoxicity studies showed that the IC50 of GNRs-TPGS-PTX NC-gel with laser irradiation decreased to ~178-folds compared with PTX alone in drug-resistant SW620 AD300 cells. In the in vivo efficacy test, after laser irradiation, the GNRs-TPGS-PTX NC-gel showed similar tumor volume inhibition compared with GNRs-gel at the beginning. However, after 14 days, the tumor volume of the mice treated with GNRs-gel quickly increased, while that of the mice treated with GNRs-TPGS-PTX NC-gel remained controllable due to the long-term chemotherapeutic effect of TPGS-PTX NC. The mice treated with GNRs-TPGS-PTX NC-gel also showed no weight loss and obvious organ damages and lesions during the treatment, indicating a low systemic side effect profile and a good biocompatibility. Conclusion: Overall, the nano-complex may serve as a promising local therapeutic patch against MDR CRC with one-time dosing to achieve a long-term tumor control. The doses of PEG-GNRs and TPGS-PTX NC can be easily adjusted before use according to patient-specific characteristics potentially making it a personalized therapeutic platform.
关键词： in situ hydrogel,tumor recurrence,gold nanorods,paclitaxel nanocrystals,TPGS
更新于2025-09-23 15:23:52
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Functional chlorin gold nanorods enable to treat breast cancer by photothermal/photodynamic therapy
摘要： Background: The existing chemo/radiotherapy fail to eliminate cancer cells due to the restriction of either drug resistance or radio tolerance. The predicament urges researchers to continuously explore alternative strategy for achieving a potent curative effect. Methods: Functional chlorin gold nanorods (Ce6-AuNR@SiO2-d-CPP) were fabricated aiming at treating breast cancer by photothermal/photodynamic therapy (PTT/PDT). The nanostructure was developed by synthesizing Au nanorods as the photothermal conversion material, and by coating the pegylated mesoporous SiO2 as the shell for entrapping photosensitizer Ce6 and for linking the D-type cell penetrating peptide (d-CPP). The function of Ce6-AuNR@SiO2-d-CPP was verified on human breast cancer MCF-7 cells and MCF-7 cells xenografts in nude mice. Results: Under combinational treatment of PTT and PDT, Ce6-AuNR@SiO2-d-CPP demonstrated a strong cytotoxicity and apoptosis inducing effects in breast cancer cells in vitro, and a robust treatment efficacy in breast cancer-bearing nude mice. The uptake mechanism involved the energy-consuming caveolin-mediated endocytosis, and Ce6-AuNR@SiO2-d-CPP in PTT/PDT mode could induce apoptosis by multiple pathways in breast cancer cells. Conclusion: Ce6-AuNR@SiO2-d-CPP demonstrated a robust efficacy in the treatment of breast cancer by photothermal/photodynamic therapy. Therefore, the present study could offer a new promising strategy to treat the refractory breast cancer.
关键词： PTT/PDT,apoptosis,cellular uptake,functional chlorin gold nanorods,cell penetrating peptide,cytotoxicity
更新于2025-09-23 15:23:52
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Rod in Tube: A Novel Nanoplatform for Highly Effective Chemo-photothermal Combination Therapy Towards Breast Cancer
摘要： Gold nanorods (GNRs) and doxorubicin (DOX) were loaded into the lumen of halloysite nanotubes (HNTs) via a rapid synthesis process (2 min) and physical adsorption. The targeting molecules of folic acid (FA) are then conjugated to HNTs via reactions with bovine serum albumin (BSA). The formation of GNRs in HNTs was verified by different techniques. The Au-HNTs-DOX@BSA-FA shows maximum of 26.8 oC temperature rising after 8 min 808-nm laser irradiation under 0.8 W cm-2. The functionalized HNTs exhibited stronger chemotherapeutic effect under laser irradiation, since the laser could promote the release of DOX and temperature rising. Au-HNTs-DOX@BSA-FA treated MCF-7 cells exhibited survival rate of 7.4% after laser irradiation. Au-HNTs-DOX@BSA-FA treatment do not induce an obvious toxicity in blood biochemistry, liver and kidney function in normal mice. In vivo chemo-photothermal treatment towards 4T1-bearing mice suggested Au-HNTs-DOX@BSA-FA exhibited remarkable tumor-targeted efficiency and good controlled-release effect for DOX. Also, the nanoparticles exhibited a rapid photothermal performance and inhibiting ability of the growth of tumor. Due to the synergistic effect of chemical-photothermal therapy, the toxicity of DOX to normal tissues was reduced on the premise of ensuring the same curative effect with a low dosage of 0.32 mg kg-1. This novel chemo-photothermal therapy nanoplatform provided a safe, rapid, effective, and cheap choice for treatment of breast tumor both in vitro and in vivo.
关键词： doxorubicin,photothermal therapy,halloysite nanotubes,chemo-photothermal therapy,gold nanorods
更新于2025-09-23 15:23:52
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Hierarchical assembly of gold nanorods stripe patterns for sensing and cells alignment
摘要： Hierarchical assemblies of nano-material superstructure with controlled orientation affords a multitude of novel properties of plasmonics and broadly applications. Yet constructing multi-functional superstructures with positioning nanoparticles in desired locations remain challenges. Herein, gold nanorods (GNRs) assembled in stripe patterns with controlled orientation and structures in millimetre scale for versatile application are achieved. Applications of patterned GNRs in sensing enhancement and engineering mammalian cells alignment are investigated experimentally. The performance of patterned GNRs in surface enhanced Raman scattering (SERS) and electrical sensing are found in orientational dependence. The SERS signals of vertically arranged GNRs arrays exhibit double folder intensity than horizontally arranged. In contrast, the horizontally arranged GNRs exhibit twice high electrical conductivity. The system is further explored to pattern mammalian cells, for the first time, we reveal nanostructured topography of GNRs confine cells to specific region, direct the adhesion and extension of living cells, which open up a broad application in tissue engineering and biosensing.
关键词： Gold nanorods,Cell patterns,Surface enhanced Raman scattering,Controllable orientation
更新于2025-09-23 15:23:52
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Comparison of turn-on and ratiometric fluorescent G-quadruplex aptasensor approaches for the detection of ATP
摘要： Two fluorescent aptasensor methods were developed for the detection of ATP in biochemical systems. The first method consisted of a label-free fluorescent Bturn-on^ approach using a guanine-rich ATP aptamer sequence and the DNA-binding agent berberine complex. In the presence of ATP, the ATP preferentially binds with its aptamer and conformationally changes into a G-quadruplex structure. The association of berberine with the G-quadruplex results in the enhancement of the fluorescence signal of the former. The detection limit of ATP was found to be 3.5 μM. Fluorescence, circular dichroism and melting temperature (Tm) experiments were carried out to confirm the binding specificity and structural changes. The second method employs the ratiometric fluorescent approach based on the Forster resonance energy transfer (FRET) for the detection of ATP using berberine along with a quencher (AuNRs, AgNPs) and a fluorophore (red quantum dots (RQDs), carbon dots (CDs)) labeled at 5′ and 3′ termini of the ATP-binding aptamer sequence. Upon addition of ATP and berberine, ATP specifically binds with its aptamer leading to the formation of G-quadruplex, and similarly, berberine also binds to the G-quadruplex. This leads to an enhancement of fluorescence of berberine while that of RQD and CDs were significantly quenched via FRET. The respective detection limits calculated were 3.6 μM and 3.8 μM, indicating these fluorescent aptasensor methods may be used for a wide variety of small molecules.
关键词： Aptasensor,Adenosine-5′-triphosphate,Gold nanorods,Fluorescence,FRET,Berberine
更新于2025-09-23 15:22:29
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Photothermal Ablation of Cancer Cells by Albumin-Modified Gold Nanorods and Activation of Dendritic Cells
摘要： Nanoparticle-mediated photothermal therapy has been widely studied for cancer treatment. It is important to disclose how photothermally ablated tumor cells trigger immune responses. In this study, bovine serum albumin (BSA)-coated gold nanorods (BSA-coated AuNRs) were prepared and used for photothermal ablation of breast tumor cells. The BSA-coated AuNRs showed high photothermal conversion efficiency and good photothermal ablation effect towards tumor cells. The ablated tumor cells were co-cultured with immature dendritic cells (DCs) through a direct cell contacting model and diffusion model to confirm the stimulatory effects of cell–cell interaction and soluble factors released from ablated tumor cells. The results indicated that photothermally ablated tumor cells induced immune-stimulatory responses of DCs through both cell–cell interaction and soluble factors. The results should be useful for synergistic photothermal-immunotherapy of primary and metastatic cancer.
关键词： gold nanorods,cellular uptake,photothermal ablation,cancer therapy,photothermal therapy,immune responses
更新于2025-09-23 15:22:29
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Chitosan/fucoidan multilayer coating of gold nanorods as highly efficient near-infrared photothermal agents for cancer therapy
摘要： Photothermal therapy (PTT) using chitosan/fucoidan multilayer coating of gold nanorods (CS/F-GNRs) has emerged as an alternative strategy for cancer therapy. In this study, biocompatible CS/F-GNRs were synthesized as a new generation of photothermal therapeutic agents for in vivo cancer treatments owing to their good biocompatibility, photostability, and strong absorption in the near-infrared (NIR) region. The CS/F-GNRs showed a good size distribution (51.87 ± 3.03 nm), and the temperature variation of the CS/F-GNRs increased by 54.4 °C after laser irradiation (1.0 W/cm2) for 5 min. The in vitro photothermal efficiency of CS/F-GNRs indicated that significantly more cancer cells were killed under laser irradiation at 1.0 W/cm2 for 5 min. On the 20th day of treatment, the MDA-MB-231 tumor cells in mice treated with CS/F-GNRs under laser irradiation had almost completely disappeared. Therefore, the biocompatible CS/F-GNRs have shown great promise as safe and highly efficient near-infrared photothermal agents for future cancer therapy.
关键词： Multilayer,Chitosan,Gold nanorods,Fucoidan,Photothermal therapy
更新于2025-09-23 15:22:29