Search results for "Colloidal gold"
showing 10 items of 161 documents
Immunochromatographic Assay for Quantitation of Milk Progesterone.
1996
We describe a rapid immunochromatographic method for the quantitation of progesterone in bovine milk. The method is based on a 'competitive' assay format using the monoclonal antibody to progesterone and a progesterone-protein conjugate labelled with colloidal gold particles. The monoclonal antibody to progesterone is immobilized as a narrow detection zone on a porous membrane. The sample is mixed with colloidal gold particles coated with progesterone-protein conjugate, and the mixture is allowed to migrate past the detection zone. Migration is facilitated by capillary forces. The amount of labelled progesterone-protein conjugate bound to the detection zone, as detected by photometric scann…
Electrochemical detection of uric acid and ascorbic acid using r-GO/NPs based sensors
2021
Abstract A sensitive and selective electrochemical sensor, based on reduced graphene oxide and gold nanoparticles obtained by simple co-electrodeposition, was developed for the detection of uric acid and ascorbic acid. Because of the electrochemical oxidation of both uric and ascorbic acid depending on the pH, the sensor performances were studied at different pH values. Excellent results were obtained for uric acid detection in a linear range from 10 to 500 µmol dm−3 with a sensitivity of 0.31 µA cm−2 µM−1. A limit of detection and quantification of 3.6 µM and 10.95 µmol dm−3, respectively, was calculated. Sensors showed good selectivity toward different interfering species present in the m…
Resorcinol Functionalized Gold Nanoparticles for Formaldehyde Colorimetric Detection
2019
[EN] Gold nanoparticles functionalized with resorcinol moieties have been prepared and used for detecting formaldehyde both in solution and gas phases. The detection mechanism is based on the color change of the probe upon the aggregation of the nanoparticles induced by the polymerization of the resorcinol moieties in the presence of formaldehyde. A limit of detection of 0.5 ppm in solution has been determined. The probe can be deployed for the detection of formaldehyde emissions from composite wood boards.
Characterization of Emergence of the Coulomb Blockade in a Pearl-Like DNA-AuNP Assembly
2023
Due to its superior self-assembly properties and vast functionalization pos-sibilities DNA has long been one of the most promising candidates forfabrication of nanoscale electrical components using molecular buildingblocks. There exist already many demonstrations on optical devices based onorganizing metallic nanoparticles (NP) via DNA self-assembly, but despite thepromises only few DNA based electrical devices or studies have been realizedso far. Here we study the gold NP conjugated and metallized DNA TX-tile-structure, which we recently showed to exhibit the room temperature Coulombblockade, the pre-requisition for a single electron transistor. The properties ofthe obtained Coulomb blocka…
Electrochemical detection of dopamine with negligible interference from ascorbic and uric acid by means of reduced graphene oxide and metals-NPs base…
2021
Abstract Dopamine is an important neurotransmitter involved in many human biological processes as well as in different neurodegenerative diseases. Monitoring the concentration of dopamine in biological fluids, i.e., blood and urine is an effective way of accelerating the early diagnosis of these types of diseases. Electrochemical sensors are an ideal choice for real-time screening of dopamine as they can achieve fast, portable inexpensive and accurate measurements. In this work, we present electrochemical dopamine sensors based on reduced graphene oxide coupled with Au or Pt nanoparticles. Sensors were developed by co-electrodeposition onto a flexible substrate, and a systematic investigati…
Partial Reduction and Selective Transfer of Hydrogen Chloride on Catalytic Gold Nanoparticles
2017
© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim HCl in solution accepts electron density from Au NPs and partially reduces at room temperature, as occurs with other simple diatomic molecules, such as O2 and H2. The activation can be run catalytically in the presence of alkynes to give exclusively E-vinyl chlorides, after the regio- and stereoselective transfer of HCl. Based also on this method, vinyl chloride monomer (VCM) can be produced in a milder and greener way than current industrial processes.
Gold nanoparticles/electrochemically expanded graphite composite: A bifunctional platform toward glucose sensing and SERS applications
2019
Abstract An integrated nanogold/expanded graphite based sensor was fabricated by a former electrochemical etching of the pencil lead electrode (PLE) and a later in-situ deposition of gold nanoparticles (AuNPs). The electrochemical pretreatment of PLE (EPLE) created a 3D graphene-like surface, enhanced the electrode surface area and facilitated the electron transfer ability within 5 min without any hazardous chemicals added. The obtained AuNPs/EPLE sensor had an excellent electrochemical response to glucose with a wide linear concentration range, from 0.05 to 38 mM and 38 to 60 mM, and a low detection limit of 5 μM (S/N = 3). Furthermore, the AuNPs/EPLE sensor was successfully employed to de…
Mapping the plasmonic response of gold nanoparticles embedded in TiO2thin films
2015
We present the mapping of the plasmonic properties of gold nanoparticles that are embedded in a TiO2 thin film deposited over two different substrates, glass and silicon. An improved electron energy-loss spectroscopy (EELS) imaging technique was used to extract plasmon maps with nanometre resolution. Several representative cases of randomly dispersed NPs have been examined to carefully evaluate surrounding effects on the optical response of such nanostructured material. Data were compared to analytical calculations and showed good agreement. These results validate previous structural and far-field optical results and provide a clear description of the optical phenomena that take place at a …
Glycopeptide-functionalized gold nanoparticles for antibody induction against the tumor associated mucin-1 glycoprotein
2015
We report the preparation of gold nanoparticle (AuNP)-based vaccine candidates against the tumor-associated form of the mucin-1 (MUC1) glycoprotein. Chimeric peptides, consisting of a glycopeptide sequence derived from MUC1 and the T-cell epitope P30 sequence were immobilized on PEGylated AuNPs and the ability to induce selective antibodies in vivo was investigated. After immunization, mice showed significant MHC-II mediated immune responses and their antisera recognized human MCF-7 breast cancer cells. Nanoparticles designed according to this report may become key players in the development of anticancer vaccines.