- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Controlled synthesis of colloidal monodisperse gold nanoparticles in a wide range of sizes; investigating the effect of reducing agent
摘要： The diverse applications of gold nanoparticles (Au-NPs) with sizes less than 50nm require a comprehensive information about how to produce Au-NPs with different sizes and narrow size distributions for a desired application. In this work, a wide range of sizes of Au-NPs from 2.5 to 35nm has been synthesized by using two reducing agents of sodium citrate and sodium borohydride. We have studied the dependency of the size, polydispersity, surface potential, plasmonic spectrum, and pH of the resultant Au-NPs on the reducing agents' concentrations. The findings show that uniform and monodispersed Au-NPs can only be produced in specific ranges of concentrations of the reducing agents. In addition, the absorption spectra of Au-NPs cannot uniquely determine the dominant size of the nanoparticles and polydispersity of the sizes is an important parameter. Measuring Zeta potential of the Au-NPs shows that by increment of pH of the solutions, the surface potential in both methods monotonically increases which results in more stability of the nanoparticles.
关键词： Polydispersity,Gold Nanoparticles,Size Distribution,Reducing agent,Surface Potential
更新于2025-09-19 17:13:59
-
Establishment of a universal and sensitive plasmonic biosensor platform based on the hybridization chain reaction (HCR) amplification induced by a triple-helix molecular switch
摘要： Herein, we established a universal and sensitive plasmonic sensing strategy for biomolecule assays by coupling the hybridization chain reaction (HCR) strategy and a triple-helix molecular switch. Upon the recognition of the target, a single-stranded DNA as a universal trigger (UT) was released from the triple-helix molecular switch (THMS). Thus, the HCR process can be triggered between two hairpins M1 and M2, resulting in the aggregation of gold nanoparticles (AuNPs) via the hybridization between the tail sequence on M1 (or M2) and a DNA–AuNP probe with a dramatic change in the absorbance at 521 nm. More specifically, the strategy, which was conducted by the introduction of target-specific recognition of THMS and universalized by virtue of altering the aptamer or DNA sequence without changing the triple-helix structure, enables simple design for multiple target detection. By taking advantage of THMS, this strategy could enable stable and sensitive detection of a variety of targets including nucleic acids, small molecules and proteins, which may possess great potential for practical applications.
关键词： gold nanoparticles,biomolecule detection,plasmonic biosensor,triple-helix molecular switch,hybridization chain reaction
更新于2025-09-19 17:13:59
-
An LED-Driven AuNPs-PDMS Microfluidic Chip and Integrated Device for the Detection of Digital Loop-Mediated Isothermal DNA Amplification
摘要： The sensitive quantification of low-abundance nucleic acids holds importance for a range of clinical applications and biological studies. In this study, we describe a facile microfluidic chip for absolute DNA quantifications based on the digital loop-mediated isothermal amplification (digital LAMP) method. This microfluidic chip integrates a cross-flow channel for droplet generation with a micro-cavity for droplet tiling. DNA templates in the LAMP reagent were divided into ~20,000 water-in-oil droplets at the cross-flow channel. The droplets were then tiled in the micro-cavity for isothermal amplification and fluorescent detection. Different from the existing polydimethylsiloxane (PDMS) microfluidic chips, this study incorporates gold nanoparticles (AuNPs) into PDMS substrate through silica coating and dodecanol modification. The digital LAMP chip prepared by AuNPs-PDMS combines the benefits of the microstructure manufacturing performance of PDMS with the light-to-heat conversion advantages of AuNPs. Upon illumination with a near infrared (NIR) LED, the droplets were stably and efficiently heated by the AuNPs in PDMS. We further introduce an integrated device with a NIR heating unit and a fluorescent detection unit. The system could detect HBV (hepatitis B virus)-DNA at a concentration of 1 × 101 to 1 × 104 copies/μL. The LED-driven digital LAMP chip and the integrated device; therefore, demonstrate high accuracy and excellent performance for the absolute quantification of low-abundance nucleic acids, showing the advantages of integration, miniaturization, cost, and power consumption.
关键词： digital LAMP,gold nanoparticles,integrated device,DNA quantification
更新于2025-09-19 17:13:59
-
Enrichment and Identification of Metallothionein by Functionalized Nano-Magnetic Particles and Matrix Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry
摘要： As a low molecular weight protein with the ability of binding metal ions and high inducibility, metallothionein (MT) is often regarded as an important biomarker for assessment of heavy metal pollution in water environment. In the light of that the traditional process of enrichment and identification is time-consuming and complicated, we prepared a core-shell nanoparticle, gold-coated iron oxide nanoparticles (Fe3O4@Au NPs) herein. It possessed the advantages of fast response to magnetic fields and optical properties attributing to Fe3O4 and Au nanoparticles, respectively. The Fe3O4@Au nanoparticles could be used to enrich MT simply through Au–S interaction, and the purified proteins were determined by matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/MS). The results showed that the Fe3O4@Au nanoparticles could directly enrich MT from complex solutions and the detection limit could be as low as 10 fg mL?1.
关键词： Core-shell structure,Mass spectrometry,Low-abundant,Metallothionein,Gold nanoparticles,Magnetic nanomaterials
更新于2025-09-19 17:13:59
-
A Ratiometric Fluorescent Quantum Dot-Based Biosensor for Chlorothalonil Detection via an Inner-Filter Effect
摘要： A new sensitive sensor for detecting chlorothalonil (CHL) based on the inner-filter effect (IFE) between gold nanoparticles (AuNPs) and ratiometric fluorescent quantum dots (RF-QDs) was developed. Here, RF-QDs were designed by two different color CdTe QDs. Based on the IFE, the AuNPs can quench the fluorescence of the RF-QDs. Because of the electrostatic attraction between protamine (PRO) and the AuNPs, the PRO can restore fluorescence effectively. Papain (PAP) can easily hydrolyze PRO and causes the quench of fluorescence quenching. The addition of CHL can inhibit PAP activity and restore the fluorescent signal. Through the characterization of the structural changes of PAP, the inhibition and mechanism of CHL on PAP activity were studied. The ability of CHL to inhibit PAP activity was evaluated by measuring the fluorescence of the RF-QDs. Under the optimal conditions, this sensing platform shows a response to CHL in the range of 0.34-2320 ng/mL and a detection limit of 0.0017 ng/mL. Based on the CHL inhibition of PAP activity, the RF-QDs showed good selectivity for CHL. The practical application of the proposed system was demonstrated by detecting CHL in food and environmental samples with satisfying results.
关键词： ratiometric fluorescent quantum dots,inner-filter effect,biosensor,chlorothalonil,gold nanoparticles
更新于2025-09-19 17:13:59
-
Synergistical Use of Electrostatic and Hydrophobic Interactions for the Synthesis of a New Class of Multifunctional Nanohybrids: Plasmonic Magneto-Liposomes
摘要： By carefully controlling the electrostatic interactions between cationic liposomes, which already incorporate magnetic nanoparticles in the bilayers, and anionic gold nanoparticles, a new class of versatile multifunctional nanohybrids (plasmonic magneto-liposomes) that could have a major impact in drug delivery and controlled release applications has been synthesized. The experimental results confirmed the successful synthesis of hydrophobic superparamagnetic iron oxide nanoparticles (SPIONs) and polyethylene glycol functionalized (PEGylated) gold nanoparticles (AuNPs). The SPIONs were incorporated in the liposomal lipidic bilayers, thus promoting the formation of cationic magnetoliposomes. Different concentrations of SPIONs were loaded in the membrane. The cationic magnetoliposomes were decorated with anionic PEGylated gold nanoparticles using electrostatic interactions. The successful incorporation of SPIONs together with the modifications they generate in the bilayer were analyzed using Raman spectroscopy. The plasmonic properties of the multifunctional nanohybrids were investigated using UV-Vis absorption and (surface-enhanced) Raman spectroscopy. Their hyperthermic properties were recorded at different frequencies and magnetic field intensities. After the synthesis, the nanosystems were extensively characterized in order to properly evaluate their potential use in drug delivery applications and controlled release as a result of the interaction with an external stimulus, such as an NIR laser or alternating magnetic field.
关键词： superparamagnetic nanoparticles,hyperthermia,multifunctional nanohybrids,gold nanoparticles,magneto-liposomes
更新于2025-09-16 10:30:52
-
AuNP and ssDNA capped mesoporous silica nanoparticles for laser controlled drug release
摘要： In order to improve drug e?cacy, and reduce drug toxicity and side e?ects, a novel drug controlled release system was developed based on mesoporous silica nanoparticles (MSNs) with gold nanoparticles (AuNPs) acting as pore caps and short single-stranded DNA (ssDNA) oligomers as the linker. The synthesised composites were characterized by Fourier transform infrared spectroscopy (FTIR), powder X-ray di?raction (XRD), thermogravimetric analysis (TGA), zeta potential measurement, transmission electron microscopy (TEM) and UV-vis spectroscopy. The anticancer drug doxorubicin (Dox) was applied as a model drug to investigate the 808 nm near infrared (NIR) laser-controlled drug release behavior at di?erent pH by ?uorescence measurements. The investigation results demonstrate that this nanocarrier could achieve drug controlled release by external near-infrared (NIR) laser stimulation, which is expected to be applied in cancer therapy.
关键词： doxorubicin,near-infrared laser,single-stranded DNA,mesoporous silica nanoparticles,drug controlled release,gold nanoparticles
更新于2025-09-16 10:30:52
-
SPR responsive xylenol orange functionalized gold nanoparticles- optical sensor for estimation of Al3+ in water
摘要： Xylenol orange functionalized gold nanoparticles (XO-AuNPs), prepared by reducing HAuCl4 in presence of xylenol orange were found to be selective and sensitive for optical sensing of Al3+ in water. XO-AuNPs nanoparticles were characterized by transmission electron microscopy (TEM), x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS); the nanoparticles formed were of spherical shape and of uniform size of 3-12 nm. The interaction between Al3+ and XO-AuNPs at pH ~3 was studied by XPS analysis. XPS and TEM studies revealed that aggregation of XO-AuNPs in the presence of Al3+ takes place through analyte induced cross-linkage mechanism. Al3+ induced selective aggregation of the XO-AuNPs lead to a visual change in color of the colloidal solution from deep red to blue. The changes in characteristic absorption peak of XO-AuNPs were monitored; the ratio of A550nm/A515nm was used to quantify the concentration of Al3+ in water samples. The method gave a linear response from 50?300 ppb (R2 = 0.985) of Al3+ in drinking water with a detection limit of 12 ppb. The proposed method did not suffer any major interference from concomitant transition metal ions and anions. The developed method was simple, rapid and useful for determination of Al3+ in drinking water samples.
关键词： Aluminium,UV-visible spectroscopy,Optical sensor,Gold nanoparticles,X-ray photoelectron spectroscopy,Xylenol orange
更新于2025-09-16 10:30:52
-
[IEEE 2019 International Conference on Optical MEMS and Nanophotonics (OMN) - Daejeon, Korea (South) (2019.7.28-2019.8.1)] 2019 International Conference on Optical MEMS and Nanophotonics (OMN) - Tunable Plasmonics by Self-Assembled Stretchable Superlattices on Macroscopic Scale
摘要： We present a process to create flexible 2D superlattices of nanoparticles, self-assembled into discrete and long-range ordered clusters. The process is readily scalable and grants access to mechano-responsive nanostructures on square centimeter areas. The elastic properties of the support allow for post-assembly tailoring of the lattice periodicity. The corresponding change in collective lattice coupling results in a gradual shift of the extinction maximum upon mechanical strain. Our results give a proof-of-principle for tunable plasmonics by mechano-responsive nanostructures.
关键词： enhanced spectroscopy,lattice plasmons,mechano-plasmonics,self-assembly,gold nanoparticles
更新于2025-09-16 10:30:52
-
[IEEE 2019 16th International Multi-Conference on Systems, Signals & Devices (SSD) - Istanbul, Turkey (2019.3.21-2019.3.24)] 2019 16th International Multi-Conference on Systems, Signals & Devices (SSD) - Investigation of Laser Induced Graphene Electrodes Modified by MWNT/AuNPs for Detection of Nitrite
摘要： In this paper, a novel low cost electrode material for sensing is presented which demonstrates excellent electrochemical response to nitrite while being amenable to implementation in disposable point of care nitrite sensors. Laser induced grapheneous carbon (LIG) is based on a simple laser engraving method to fabricate electrodes by inducing conductive paths onto Kapton polymer substrate. The working electrode was modified by Gold Nanoparticles (AuNPs), multiwalled carbon nanotubes (MWCNT) and AuNPs/MWCNT. The modified electrodes were characterized by electron microscopy energy x-ray dispersive spectroscopy (SEM-EDX), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Surface morphology and electrochemical methods confirms confirm the successful implementation of LIG electrodes whose electrocatalytic performance is highly improved after modification. This suggests the synergetic effect between AuNPs and MWCNTs with the excellent conductivity and large specific surface area. By means of square wave voltammetry (SWV), the limit of detection of the proposed sensor is 6.75 μM, which is low enough for practical applications. In conclusion, AuNPs/MWCNT modified LIG electrodes demonstrated good electrochemical behavior and promising future use in disposable nitrite electrochemical sensors.
关键词： electrochemical sensing,nitrite detection,carbon nanotubes,gold nanoparticles,Laser induced graphene
更新于2025-09-16 10:30:52