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Gold nanoparticle-based plasmonic probe for selective recognition of adenosine
摘要： Adenosine, as an endogenous molecule in organisms, plays an essential role in biological processes. Here, a plasmonic probe, creatinine-Ag+/gold nanoparticle (AuNPs), is assembled for adenosine detection based on synergistic coordination on AuNPs. The A650 nm/520 nm values of AuNPs system change linearly with adenosine concentration over a range of 1.0–5.0 μM and the detection limits reached 45 nM. The adenosine detection is realized within 4 min. Furthermore, the quantitative detection of adenosine is realized by eyedropper (a function in Microsoft’s PowerPoint) for analyzing RGB value changes of colorimetric assay. Therefore, this sensor can provide accurate and rapid assay of adenosine in patients’ serum sample without complicated instrumentations.
关键词： colorimetric assay,adenosine detection,eyedropper function,gold nanoparticle,plasmonic probe
更新于2025-11-19 16:56:42
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Proof of concept of plasmonic thermal destruction of surface cancers by gold nanoparticles obtained by green chemistry
摘要： A greener approach for the design of surface plasmon resonant gold nanoparticles has been obtained with a hydrosoluble fraction of an endemic asteraceae medicinal plant. This medicinal plant is originated from Indian Ocean and demonstrates its bioreducing activity in the design of stable green nanomedicine in aqueous media. This article describes the preclinical assessment of the efficacy of these novel nanocandidates on murine model by intratumoral and intravenous injections. It definitely demonstrates two key points in the treatment of cancer: 1) optimization of the tumor microenvironment targeting by specific ligands for a limited damage on healthy tissue, 2) the need to screen the specific irradiation dose (time, power) taking into account the type of tumor.
关键词： Medicinal plant,Hyperthermia,Green nanomedicine,Plasmonic photothermal therapy,Gold nanoparticle
更新于2025-11-14 15:25:21
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Determination of 17β-estradiol by surface-enhanced Raman spectroscopy merged with hybridization chain reaction amplification on Au@Ag core-shell nanoparticles
摘要： The authors describe an aptamer-based assay for 17β-estradiol. It relies on the combined use of surface enhanced Raman scattering (SERS) and hybridization chain reaction (HCR). The aptamer against 17β-estradiol is applied as the recognition probes, and this results in excellent specificity. Specific recognition of target 17β-estradiol induce the freedom of DNA 2, which will open the stem-loop structure of probe 1 on the Au@Ag and form the partial dsDNA structure. With the nicking enzyme, the partial dsDNA will be hydrolyzed and the reside ssDNA on Au@Ag will form a small stem-loop structure. With the help of the other probe 2 modified Au@Ag and pre-immobilized probe 3 on the well of the microplate, an enzyme-free HCR can occur and tremendous Au@Ag can be assembled along the formed dsDNA in HCR, which can act as the excellent substrate for Raman measurement and greatly amplify the Raman signal of R6G on the Au@Ag. Afterwards, the key factor, ratio between probe 2-Au@Ag (P2) and probe1-Au@Ag (P1), affects the detection sensitivity is systematically optimized for the best sensing performance. The SERS signal of R6G, best measured at 1651 cm?1, increases linearly in the wide range from 1 pM to 10 nM. The detection limit can be as low as 0.1 pM.
关键词： Estrogen,Hybridization chain reaction,SERS,Food safety,Aptamer,Gold nanoparticle,Signal amplification,Environment monitoring
更新于2025-09-23 15:23:52
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Target-recycling-amplified colorimetric detection of pollen allergen using non-cross-linking aggregation of DNA-modified gold nanoparticles
摘要： Increasing prevalence of pollen allergies has raised concerns about human health. Development of a facile and precise method to detect pollen allergens would thus be of significance for environmental assessments and medical diagnoses. Here we report a sensitive colorimetric method to detect the Japanese cedar pollen allergen, Cry j 2. The method consists of two steps: a signal amplification based on the catalytic DNA hairpin self-assembly, followed by a signal transduction using the salt-induced non-cross-linking aggregation of gold nanoparticles densely modified with short DNA. The assay exhibits a detection limit of 0.2 ng/mL, which is 130-fold greater than that of the previously reported one. Moreover, the assay enables the detection of Cry j 2 spiked in soil solutions by avoiding any interference from the contaminants. The signal amplification system includes an anti-Cry j 2 DNA aptamer, which accounts for the absence of false responses to five non-target allergen proteins. The present method could be of general applicability to various proteins by using appropriate aptamers.
关键词： Surface plasmon resonance,Allergen,Aptamer,Gold nanoparticle,DNA,Cry j 2
更新于2025-09-23 15:23:52
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Highly Responsive PEG/Gold Nanoparticle Thin Film Humidity Sensor via Inkjet Printing Technology
摘要： In this study, a highly responsive humidity sensor is developed by printing gold nanoparticles (GNP) grafted with a hygroscopic polymer. These GNPs are inkjet printed to form a uniform thin film over an interdigitated electrode with controllable thickness by adjusting the printing parameters. The resistance of the printed GNP thin film decreases significantly upon exposure to water vapor and exhibits a semi-log relationship with relative humidity (RH). The sensor can detect RH variations from 1.8% to 95% with large resistance changes up to 4 order of magnitude with no hysteresis and small temperature dependence. In addition, with a thin thickness, the sensor can reach absorption equilibrium quickly with response and recovery times of ≤1.2 and ≤3 seconds, respectively. The fast response to humidity changes also allows the GNP thin film sensor to distinguish signals from intermittent humidification/dehumidification cycles with a frequency up to 2.5 Hz. The printed sensors on flexible substrates show little sensitivity to bending deformation and can be embedded in a mask for human respiratory detection. In summary, this study demonstrates the feasibility of applying printing technology for the fabrication of thin film humidity sensors, and the developed methodology can be further applied to fabricate many other types of nanoparticle based sensor devices.
关键词： inkjet printing,respiratory monitoring,Humidity sensor,gold nanoparticle,poly(ethylene glycol)
更新于2025-09-23 15:23:52
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Synthesis of Chiral Gold Nanoparticle by Direct Reduction with L and D-Serine and Enhanced Anti-Mycobacterial Activity by D-Serine Protected Gold Nanoparticle
摘要： Current situation demands more biocompatible and non-toxic nanostructures. Towards this the present study describes the synthesis of gold nanoparticle by direct reduction of tetrachloroauric acid with both D- and L-enantiomeric forms of the amino acid serine. The formation of nanoparticle was confirmed by examining different physical characteristics like surface plasmon resonance. Moreover, the retention of chirality of the reduced particle was also evident from circular dichroism spectroscopy experiment. In addition, the shielding of the nanoparticle by respective amino acid was confirmed by Scanning Electron Microscope and Energy Dispersive X-ray Analysis (SEM-EDAX). As D-serine is known to be active against Mycobacteria, examination of the biological activity of the D-serine protected particle was performed against the same. The result showed higher inhibitory activity of the particle against Mycobacterium smegmatis than D-serine alone. Thus the present study describes a new protocol for the synthesis of chiral gold nanoparticle that can be beneficial in enantioselective biological applications.
关键词： Chiral nanoparticle,D-serine,Mycobacteria,Biocompatible gold nanoparticle,L-serine
更新于2025-09-23 15:22:29
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Quantification of DNA by a Thermal-Durable Biosensor Modified with Conductive Poly(3,4-ethylenedioxythiophene)
摘要： The general clinical procedure for viral DNA detection or gene mutation diagnosis following polymerase chain reaction (PCR) often involves gel electrophoresis and DNA sequencing, which is usually time-consuming. In this study, we have proposed a facile strategy to construct a DNA biosensor, in which the platinum electrode was modified with a dual-film of electrochemically synthesized poly(3,4-ethylenedioxythiophene) (PEDOT) resulting in immobilized gold nanoparticles, with the gold nanoparticles easily immobilized in a uniform distribution. The DNA probe labeled with a SH group was then assembled to the fabricated electrode and employed to capture the target DNA based on the complementary sequence. The hybridization efficiency was evaluated with differential pulse voltammetry (DPV) in the presence of daunorubicin hydrochloride. Our results demonstrated that the peak current in DPV exhibited a linear correlation the concentration of target DNA that was complementary to the probe DNA. Moreover, the electrode could be reused by heating denaturation and re-hybridization, which only brought slight signal decay. In addition, the addition of the oxidized form of nicotinamide adenine dinucleotide (NAD+) could dramatically enhance the sensitivity by more than 5.45-fold, and the limit-of-detection reached about 100 pM.
关键词： poly(3,4-ethylenedioxythiophene),gold nanoparticle,electron transfer mediate,DNA biosensor
更新于2025-09-23 15:21:21
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Liquid-Cell Scanning Transmission Electron Microscopy and Fluorescence Correlation Spectroscopy of DNA-Directed Gold Nanoparticle Assemblies
摘要： In the use of solution-based 3D nanoarchitectures for optics, drug delivery, and cancer treatment, the precise nanoparticle architecture morphologies, architecture sizes, interparticle distances, and the assembly stability are all critical to their functionality. 3D nanoparticle architectures in solution are difficult to characterize, as few techniques can provide individualized information on interparticle spacing (defined by linkage molecule), nanoparticle assembly size, morphology, and identification of false aggregation. Bulk characterization techniques, including small angle x-ray scattering, can provide architecture sizes, though they are unable to precisely measure differences within interparticle spacings for individual architectures and can falsely measure assemblies caused by non-linkage grouped nanoparticles. Two solution-based characterization techniques were used to determine which assembly type and linkage length would produce the fastest assembly rate for large DNA-directed gold nanoparticle assemblies. In-situ liquid-cell scanning transmission electron microscopy (STEM), measured interparticle spacings between DNA-functionalized nanoparticles, and fluorescence correlation spectroscopy provided the bulk volume fraction of large and small assemblies for nanoparticle architectures that were assembled using two different types: (1) the hybrid assemblies join two complementary single-stranded DNA linkages, and (2) the bridged assemblies are comprised of single-stranded DNA (bridging component) that is double the length of two different complementary single-stranded DNA-functionalized gold nanoparticles (Fig. 1). Assembly times were tested at 24-hour intervals over 3 days. Statistics derived from the in-situ liquid-cell STEM images provided data for interparticle distance measurements, which identified the fraction of nanoparticles within the images acquired that were at the expected double-stranded DNA-binding distance of the linkages (varied in three distances for each of the two different architectures). In general, longer linkage lengths assembled in the shortest amount of time. The bridged assemblies formed fewer large architectures at 24-hours but ultimately assembled a greater fraction of nanoparticles, which was due to the longer functionalized DNA lengths for individual nanoparticles. Fluorescence correlation spectroscopy provided a bulk average of the gold nanoparticle assembly sizes over time, which supported the conclusions drawn from the in-situ liquid-cell STEM data. The microscopy provided sub-2 nanometer precision in the interparticle distances between gold nanoparticles in a solution environment. This coupled microscopy and spectroscopy characterization approach can provide more detailed information than bulk characterization methods.
关键词： gold,nanoparticle,DNA,FCS,assembly,liquid-cell TEM
更新于2025-09-23 15:21:21
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Dark Plasmon Modes in Symmetric Gold Nanoparticle Dimers Illuminated by Focused Cylindrical Vector Beams
摘要： The plasmon hybridization model of electromagnetic coupling between plasmonic nanoparticles predicts the formation of lower energy “bonding” and higher energy “antibonding” modes in analogy with the quantum mechanical description of chemical bonding. For a symmetric metallic nanoparticle dimer excited by linearly polarized light, the hybridization picture predicts that in-phase coupling of the dipole moments is optically allowed, creating bright “modes”, whereas the out-of-phase coupling is dark due to the cancellation of the oppositely oriented dipole moments (in the quasistatic approximation). These bright modes are electric dipolar in nature and readily couple to scalar (i.e., linearly or circularly polarized) beams of light. We show that focused cylindrical vector beams, specifically azimuthally and radially polarized beams, directly excite dark plasmon modes in symmetric gold nanoparticle (AuNP) dimers at normal incidence. We use single-particle spectroscopy and electrodynamics simulations to study the resonance scattering of AuNP dimers illuminated by azimuthally and radially polarized light. The electric field distributions of the focused azimuthal or radial beams are locally polarized perpendicular or parallel to the AuNP dimer axis, but with opposite directions at each particle. Therefore, the associated combinations of single-particle dipole moments are out-of-phase, and the excitation (resonance) is of so-called “dark modes”. In addition, multipole expansion of the fields associated with each scattering spectrum shows that the vector beam excitation involves driving multipolar, e.g., magnetic dipolar and electric quadrupolar, modes, and that they even dominate the scattering spectra (vs electric dipole). This work opens new opportunities for investigating dark plasmon modes in nanostructures, which are difficult to selectively excite by conventional polarized light.
关键词： electrodynamics simulations,dark plasmon modes,plasmon hybridization,single-particle spectroscopy,gold nanoparticle dimers,cylindrical vector beams
更新于2025-09-23 15:21:21
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Au nanoparticle preconcentration coupled with CE-electrochemiluminescence detection for sensitive analysis of fluoroquinolones in European eel ( <i>Anguilla anguilla</i> )
摘要： In this work, a novel method based on gold nanoparticle preconcentration coupled with CE for electrochemiluminescent detection of ciprofloxacin, enrofloxacin, ofloxacin, and norfloxacin in European eels was developed. The addition of gold nanoparticles induced the rapid enrichment of fluoroquinolones, which was simpler than the conventional enrichment approaches such as solid phase extraction and solid-phase microextraction. More than 100 times enrichment was observed after gold nanoparticle aggregation-based preconcentration. The CE-electrochemiluminescent parameters that affected the separation and detection were optimized. Under the optimized conditions, the linear ranges for the four fluoroquinolones were 0.090—8.0 μmol/L with the detection limits between 0.020 to 0.050 μmol/L. The proposed approach showed the advantages of high sensitivity, high selectivity, wide linear range, and low detection limit. It was used to analyze fluoroquinolones in European eel, and the results showed that the developed method can satisfy the detection requirements for fluoroquinolones determination in aquatic products set by China and European Union.
关键词： Capillary electrophoresis,fluoroquinolones,preconcentration,European eel,gold nanoparticle
更新于2025-09-23 15:21:01