Search results for "Gold nanoparticle"

A Colorimetric Probe for the Selective Detection of Norepinephrine Based on a Double Molecular Recognition with Functionalized Gold Nanoparticles

2019

[EN] A simple colorimetric probe for the selective and sensitive detection of neurotransmitter norepinephrine (NE), an important biomarker in the detection of tumors such as pheochromocytoma and paraganglioma, is described. The sensing strategy is based on the use of spherical gold nanoparticles functionalized with benzaldehyde and boronic acid-terminated moieties. A double molecular recognition involving on one hand the aromatic aldehyde and the aminoalcohol group of NE, and on the other hand the boronic acid and the catechol moiety of the neurotransmitter, results in analyte triggered aggregation of the gold nanoparticles, leading to a bathochromic shift of the SPR band in the UV-vis spec…

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.

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…

SYNTHESIS AND CHARACTERIZATION OF NEW AMPHIPHILIC COPOLYMERS BASED ON A POLY(HYDROXYETHYL)-D,L-ASPARTAMIDE (PHEA) FOR THE COATING OF GOLD NANOPARTICL…

2012

Enhanced efficiency in plastic planar heterojunction solar cells by AuNPs positioned at donor-acceptor interfaces

2018

A new class of copolymers containing oligothiophene moieties with different length and fullerene units have been designed and prepared by an easy and inexpensive one-step synthetic approach. The incorporation of small quantities of these copolymers into bulk heterojunction (BHJ) solar cells with donor regioregular polythiophene (P3HT) and acceptor fullerene derivate (PCBM) results in a good control of the phase separation process without further affecting the BHJ optoelectronic properties. Indeed, these copolymers allow modulating under thermal annealing the growth of domains whose size depends on the length of the copolymer repetitive units. Domain size on the same length scale of the P3HT…

Gold nanoparticles stabilized by modified halloysite nanotubes for catalytic applications

2019

A highly sustainable prototype of a flow system based on gold nanoparticles (4.2 nm) supported on thiol-functionalized halloysite nanotubes (HNTs) was developed for catalytic applications. The catalytic performances were evaluated using the reduction of 4-nitrophenol to 4-aminophenol as a model system. Under the best experimental conditions (0.0001 mol%, 1.97 × 10−8 mg of Au nanoparticles), an impressive apparent turnover frequency value up to 2 204 530 h−1 was achieved and the halloysite-based catalyst showed full recyclability even after ten cycles. The high catalytic activity confirms the importance of the use of HNTs as support for Au nanoparticles that can exert a synergistic effect bo…

Polymeric monolithic microcartridges with gold nanoparticles for the analysis of protein biomarkers by on-line solid-phase extraction capillary elect…

2020

In this study, polymeric monoliths with gold nanoparticles (AuNP@monolith) were investigated as microcartridges for the analysis of protein biomarkers by on-line solid-phase extraction capillary electrophoresis-mass spectrometry (SPE-CE-MS). “Plug-and-play” microcartridges (7 mm) were prepared from a glycidyl methacrylate (GMA)-based monolithic capillary column (5 cm x 250 µm i.d.), which was modified with ammonia and subsequently functionalized with gold nanoparticles (AuNPs). The performance of these novel microcartridges was evaluated with human transthyretin (TTR), which is a protein related to different types of familial amyloidotic polyneuropathies (FAP). Protein retention depended on…

Conformation and dynamics of the ligand shell of a water-soluble Au102 nanoparticle

2016

Inorganic nanoparticles, stabilized by a passivating layer of organic molecules, form a versatile class of nanostructured materials with potential applications in material chemistry, nanoscale physics, nanomedicine and structural biology. While the structure of the nanoparticle core is often known to atomic precision, gaining precise structural and dynamical information on the organic layer poses a major challenge. Here we report a full assignment of 1H and 13C NMR shifts to all ligands of a water-soluble, atomically precise, 102-atom gold nanoparticle stabilized by 44 para-mercaptobenzoic acid ligands in solution, by using a combination of multidimensional NMR methods, density functional t…

Assembly of citrate gold nanoparticles on hydrophilic monolayers

2016

Abstract Self-assembled monolayers (SAMs) as model surfaces were linked onto planar gold films thorough lipoic acid or disulfide groups. The molecules used were polyethylene glycol (EG-S-S), N -[tris-(hydroxymethyl)methyl]acrylamide polymers with and without lipoic acid (Lipa-pTHMMAA and pTHMMAA) and a lipoic acid triazine derivative (Lipa-MF). All the layers, but Lipa-MF with a primary amino group were hydroxyl terminated. The layers were characterized by contact angle measurements and atomic force microscopy, AFM. Citrate stabilized nanoparticles, AuNPs in water and phosphate buffer were allowed to assemble on the layers for 10 min and the binding was followed in real-time with surface pl…

Comparative evaluation of the impact on endothelial cells induced by different nanoparticle structures and functionalization

2015

In the research field of nanoparticles, many studies demonstrated a high impact of the shape, size and surface charge, which is determined by the functionalization, of nanoparticles on cell viability and internalization into cells. This work focused on the comparison of three different nanoparticle types to give a better insight into general rules determining the biocompatibility of gold, Janus and semiconductor (quantum dot) nanoparticles. Endothelial cells were subject of this study, since blood is the first barrier after intravenous nanoparticle application. In particular, stronger effects on the viability of endothelial cells were found for nanoparticles with an elongated shape in compa…