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Plasmonic gel nanocomposites for detection of high energy electrons
摘要： Radiation therapy is a common treatment modality employed in the treatment of cancer. High energy photons are the primary source of radiation but when administered, they leave an exit dose resulting in radiation damage to the adjacent healthy tissues. To overcome this, high energy electrons are employed in cases of skin cancer to minimize radiation induced toxicity. Despite these advances, measurement of delivered radiation remains a challenge due to limitations with existing dosimeters including labor intensive fabrication, complex read-out techniques and post-irradiation instability. To overcome these limitations, we have developed a novel colorimetric plasmonic gel nanocomposite for the detection of therapeutic levels of radiation delivered in electron beam therapy. The plasmonic nanocomposite consists of an agarose gel matrix encapsulating precursor gold ions, which are reduced to gold nanoparticles as a result of exposure to high energy electrons. The formation of gold nanoparticles renders a change in color to the agarose matrix, resulting in the formation of plasmonic gel nanocomposites. The intensity of the color formed exhibits a linear relation with the delivered electron dose, which can be quantified using absorbance spectroscopy. The plasmonic gel nanocomposites were able to detect doses employed in fractionated electron therapy, including in an anthropomorphic phantom used for planning radiation treatments in the clinic. Furthermore, the use of glutathione as a quenching agent facilitated qualitative and quantitative spatial mapping of the delivered dose. Our results indicate that the ease of fabrication, simplicity of detection and quantification using absorbance spectroscopy, determination of spatial dose profiles, and relatively low cost make the plasmonic gel nanocomposite technology attractive for detecting electron doses in the clinic.
关键词： gold nanoparticles,Plasmonic gel nanocomposites,radiation therapy,high energy electrons,absorbance spectroscopy
更新于2025-09-23 15:19:57
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Self-assembled Ln(III) cyclen-based micelles and AuNPs conjugates as candidates for luminescent and magnetic resonance imaging (MRI) agents
摘要： The tetra-substituted heptadentate cyclen (1,4,7,10-tetraazacyclododecane) based Eu(III)/Tb(III)/Gd(III)-complexes 1.Ln and 2.Ln were developed. 1.Eu/Tb and 2.Eu/Tb were employed in the formation of luminescent self-assembling ternary structures, and we demonstrate that only in the presence of appropriate sensitizing antennae, was the lanthanide-emission of 1.Eu/Tb and 2.Eu/Tb ‘switched on’. 1.Gd/2.Gd were developed as potential MIR contrast agents, and employed in NMRD-measurements, where their relaxivity was investigated, and their (relatively high) r1 values determined. The formation of a self-assembled micelle-type structure was clearly observed for 2.Gd. The functionalised gold nanoparticles 1.Ln-AuNP were also synthesized from 1.Ln. As for the free complexes, the Ln-emission was ‘switched on’ for 1.Eu/Tb-AuNP in the presence of the antennae. NMRD measurements indicated that the relaxivity for the 1.Gd-AuNP systems was very high, with a value of 445 s-1mM-1 (at 400 MHz), demonstrating the cumulative effect of the relatively high number of 1.Gd complexes on the surface of the AuNP.
关键词： gold nanoparticles,lanthanides,Supramolecular chemistry,luminescence,MRI contrast agents,cyclen complexes
更新于2025-09-23 15:19:57
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Gold nanoparticles doped metal-organic frameworks as near-infrared light-enhanced cascade nanozyme against hypoxic tumors
摘要： We report gold nanoparticles (AuNPs) doped iron-based metal-organic frameworks (GIM) which displays near-infrared light (NIR)-enhanced cascade nanozyme against hypoxic tumors. Due to the strong protein adsorption-induced surface passivation, AuNPs suffer from the loss of glucose oxidase (GOx) activity. However, GIM could protect the GOx-like activity of AuNPs with the satisfactory shield capability. In addition, GIM exhibited excellent photothermal conversion ability and unique NIR light-enhanced GOx-like activity, which could efficiently increase the endogenous H2O2 production. Meanwhile, as the produced H2O2 is converted by GIM into O2 and highly toxic (cid:1668)OH. Thus, GIM-catalyzed cascade reactions with NIR light irradiation not only offer the O2 but also promote the reactive oxygen species (ROS) generation at tumor sites. The produced O2 could be further applied to AuNPs catalytic oxidation of glucose and relieve hypoxic condition of tumor microenvironment (TME). As a proof-of-concept study, GIM demonstrates the admirable tumor ablation under NIR irradiation in vivo.
关键词： near-infrared light,metal-organic frameworks,reactive oxygen species,nanozyme,gold nanoparticles
更新于2025-09-23 15:19:57
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Signal amplification and quantification on lateral flow assays by laser excitation of plasmonic nanomaterials
摘要： Lateral flow assay (LFA) has become one of the most widely used point-of-care diagnostic methods due to its simplicity and low cost. While easy to use, LFA suffers from its low sensitivity and poor quantification, which largely limits its applications for early disease diagnosis and requires further testing to eliminate false-negative results. Over the past decade, signal enhancement strategies that took advantage of the laser excitation of plasmonic nanomaterials have pushed down the detection limit and enabled quantification of analytes. Significantly, these methods amplify the signal based on the current LFA design without modification. This review highlights these strategies of signal enhancement for LFA including surface enhanced Raman scattering (SERS), photothermal and photoacoustic methods. Perspectives on the rational design of the reader systems are provided. Future translation of the research toward clinical applications is also discussed.
关键词： gold nanoparticles,lateral flow assay,nanoparticle heating,signal amplification and quantification,SERS
更新于2025-09-23 15:19:57
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HCN emission by a Polydesmid Millipede Detected Remotely by Reactive Adsorption on Gold Nanoparticles Followed by Laser Desorption/Ionization Mass Spectrometry (LDI-MS)
摘要： Hydrocyanic acid (HCN) is a well-known defensive allomone in the chemical arsenal of millipedes in the order Polydesmida. The presence of HCN in the headspace vapor of adult Xystocheir dissecta (Wood, 1867), a common millipede from the San Francisco Bay Area, was traced by laser desorption/ionization-mass spectrometry (LDI-MS). To accomplish this, the headspace vapor surrounding caged, live millipedes was allowed to diffuse passively over gold-nanoparticle (AuNP) deposits placed at various distances from the emitting source. The stainless steel plates with AuNP deposits were removed and irradiated by a 355-nm laser. The gaseous ions generated in this way were detected by time-of-flight mass spectrometry. The intensity of the mass spectrometric peak detected at m/z 249 for the Au(CN)2? complex anion was compared to that of the residual Au? signal (m/z 197). Using this procedure, HCN vapors produced by the live millipedes could be detected up to 50 cm away from the source. Furthermore, the addition of H2O2, as an internal oxygen source for the gold cyanidation reaction that takes place in the AuNP deposits, significantly increased the detection sensitivity. Using the modified H2O2 addition procedure, HCN could now be detected at 80 cm from the source. Moreover, we found a decreasing intensity ratio of the Au(CN)2?/Au? signals as the distance from the emitting source increased, following an exponential-decay distribution as predicted by Fick’s law of diffusion.
关键词： Gold nanoparticles (AuNP),Polydesmida,Laser desorption/ionization (LDI),Millipedes,Hydrogen cyanide (HCN),Hydrogen peroxide (H2O2),Allomones
更新于2025-09-23 15:19:57
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<p>The Pimpled Gold Nanosphere: A Superior Candidate for Plasmonic Photothermal Therapy</p>
摘要： Background: The development of highly efficient nanoparticles to convert light to heat for anti-cancer applications is quite a challenging field of research. Methods: In this study, we synthesized unique pimpled gold nanospheres (PGNSs) for plasmonic photothermal therapy (PPTT). The light-to-heat conversion capability of PGNSs and PPTT damage at the cellular level were investigated using a tissue phantom model. The ability of PGNSs to induce robust cellular damage was studied during cytotoxicity tests on colorectal adenocarcinoma (DLD-1) and fibroblast cell lines. Further, a numerical model of plasmonic (COMSOL Multiphysics) properties was used with the PPTT experimental assays. Results: A low cytotoxic effect of thiolated polyethylene glycol (SH-PEG400-SH-) was observed which improved the biocompatibility of PGNSs to maintain 89.4% cell viability during cytometry assays (in terms of fibroblast cells for 24 hrs at a concentration of 300 μg/mL). The heat generated from the nanoparticle-mediated phantom models resulted in ΔT=30°C, ΔT=23.1°C and ΔT=21°C for the PGNSs, AuNRs, and AuNPs, respectively (at a 300 μg/mL concentration and for 325 sec). For the in vitro assays of PPTT on cancer cells, the PGNS group induced a 68.78% lethality (apoptosis) on DLD-1 cells. Fluorescence microscopy results showed the destruction of cell membranes and nuclei for the PPTT group. Experiments further revealed a penetration depth of sufficient PPTT damage in a physical tumor model after hematoxylin and eosin (H&E) staining through pathological studies (at depths of 2, 3 and 4 cm). Severe structural damages were observed in the tissue model through an 808-nm laser exposed to the PGNSs. Conclusion: Collectively, such results show much promise for the use of the present PGNSs and photothermal therapy for numerous anti-cancer applications.
关键词： gold nanoparticles,photothermal therapy,plasmonic,colorectal cells,pathology
更新于2025-09-23 15:19:57
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Actuated plasmonic nanohole arrays for sensing and optical spectroscopy applications
摘要： Herein, we report a new approach to rapidly actuate the plasmonic characteristics of thin gold films perforated with nanohole arrays that are coupled with arrays of gold nanoparticles. The near-field interaction between the localized and propagating surface plasmon modes supported by the structure was actively modulated by changing the distance between the nanoholes and nanoparticles and varying the refractive index symmetry of the structure. This approach was applied by using a thin responsive hydrogel cushion, which swelled and collapsed by a temperature stimulus. The detailed experimental study of the changes and interplay of localized and propagating surface plasmons was complemented by numerical simulations. We demonstrate that the interrogation and excitation of the optical resonance to these modes allow the label-free SPR observation of the binding of biomolecules, and is applicable for in situ SERS studies of low molecular weight molecules attached in the gap between the nanoholes and nanoparticles.
关键词： gold nanoparticles,responsive hydrogel,plasmonic nanohole arrays,surface plasmon resonance,SERS
更新于2025-09-23 15:19:57
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Light-Induced Coalescence of Plasmonic Dimers and Clusters
摘要： The properties of nanoplasmonic structures depend strongly on their geometry, creating the need for high-precision control and characterization. Here, by exploiting the low activation energy of gold atoms on nanoparticle surfaces, we show how laser irradiation re-shapes nanoparticle dimers. Time-course dark-field micro-spectroscopy allows this process to be studied in detail for individual nanostructures. Three regimes are identified: facet growth, formation of a conductive bridge between particles, and bridge growth. Electromagnetic simulations confirm the growth dynamics and allow measurement of bridge diameter, found to be highly reproducible and also self-limiting. Correlations in spectral resonances for the initial and final states give insights into the energy barriers for bridge growth. Dark-field microscopy shows that coalescence of multiple gaps in nanoparticle clusters can be digitally triggered, with each gap closing after discrete increases in irradiation power. Such control is important for light-induced nanowire formation or trimming of electronic and optoelectronic devices.
关键词： nanoparticle coalescence,gold nanoparticles,optical spectroscopy,plasmonics,sintering,nanoparticle dimers
更新于2025-09-23 15:19:57
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Biologically Responsive Plasmonic Assemblies for Second Near-Infrared Window Photoacoustic Imaging-Guided Concurrent Chem-Immunotherapy
摘要： We developed dual biologically responsive nanogapped gold nanoparticle vesicles loaded with immune inhibitor and carried with anticancer polymeric prodrug for synergistic concurrent chemo-immunotherapy against primary and metastatic tumors, along with guided cargo release by photoacoustic (PA) imaging in the second near-infrared (NIR-II) window. The responsive vesicle was prepared by self-assembly of nanogapped gold nanoparticles (AuNNPs) grafted with poly(ethylene glycol) (PEG) and dual pH/GSH-responsive polyprodrug poly(SN38-co-4-vinyl pyridine) (termed as AuNNP@PEG/PSN38VP), showing intense PA signal in the NIR-II window. The effect of the rigidity of hydrophobic polymer PSN38VP on the assembly structures and the formation mechanism of AuNNP@SN38 Ve were elucidated by computational simulations. The immune inhibitor BLZ-945 was encapsulated into the vesicles, resulting in pH-responsive release of BLZ-945 for targeted immunotherapy, followed by the dissociation of the vesicles into single AuNNP@PEG/PSN38VP. The hydrophilic AuNNP@PEG/PSN38VP nanoparticles could penetrate deep into the tumor tissues, and release the anticancer drug SN38 under the reductive environment. PA signal in the NIR-II window in the deep tumor region was obtained. The BLZ-945 loaded vesicle enabled enhanced PA imaging-guided concurrent chemo-immunotherapy efficacy, inhibiting the growth of both primary tumors and metastatic tumors.
关键词： the second NIR window,amphiphilic nanogapped gold nanoparticles,polymeric prodrug,chemo-immunotherapy,photoacoustic imaging
更新于2025-09-23 15:19:57
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Hybrid Au@alendronate nanoparticles as dual chemo-photothermal agent for combined cancer treatment
摘要： A gold therapeutic nanoplatform with the same molecule used as reductant, coating and therapeutic agent has been developed in a one-pot, one-phase process using alendronate, a drug from the bisphosphonate family known for its antitumor effects. In addition, the core made of gold nanoparticles (NPs) brings thermal functionalities under irradiation within the first biological window (650–900 nm). The Au@alendronate nanoplatform thus provided a combined antitumor activity through drug delivery and photothermal therapy. Au@alendronate NPs inhibited in vitro the proliferation of prostate cancer cells (PC3) in a dose-dependent manner, with an IC50 value of 100 μM. Under NIR irradiation a temperature increase was observed leading to a reduction of the IC50 value to 1 μM, with total tumor cell death at 100 μM.
关键词： alendronate,cancer treatment,bisphosphonate,photothermia,gold nanoparticles
更新于2025-09-23 15:19:57