1,721,050 research outputs found
Thin films of metal porphyrin-phtalocyanine blend: as a single nanostructured thin layer can became an optochemical sensors array
No full textA reusable optical biosensor for the ultrasensitive and selective detection of unamplified human genomic DNA with gold nanostars
No full textA Surface Plasmon Resonance imaging (SPRi) based DNA sensors for the selective and ultrasensitive human genomic DNA detection, directly extracted from lymphocytes (bypassing PCR amplification), is reported. To achieve DNA detection, a rationally chosen star-shaped nanoparticle (NP), namely gold nanostar (AuNS), has been applied, for the first time, in a sandwich-like assay based on the selective capturing of specific DNA targets and the subsequent signal amplification by a secondary DNA probe linked to AuNS. The plasmonic profile, size and electric field enhancements at the star tips contributed to the maximization of plasmon coupling between LSPs and SPs as aimed for analytical signal magnification. The system was first tested using short synthetic DNA target sequences and applied to DNA biosensing, lowering 610-fold the detection limit from 6.1nM (without NSs labeling) to 10pM (with NSs labeling). Then the biosensor was applied to genomic DNA samples, extracted from human lymphocytes and undergoing only to a simple ultrasonic fragmentation, lowering (~435 fold) the detection limit from 3.0fM (without NSs labeling) to 6.9aM (with NSs labeling). Thanks to the assay optimization, we proved that tuning the NSs surface coverage with DNA linked to nanoparticles is crucial not only for the increase of signals but also for the regenerability/reusability of the biosensor for tens of measurement cycles
Spin-coated thin films of different metal phthalocyanines and porphyrin-phthalocyanine blend for optochemical sensors of volatile organic compounds
No full textArsenate reductase from Thermus thermophilus conjugated to polyethylene glycol-stabilized gold nanospheres allow trace sensing and speciation of arsenic ions.
No full textWater sources pollution by arsenic ions is a serious environmental problem all around the world. Arsenate reductase enzyme (TtArsC) from Thermus thermophilus extremophile bacterium, naturally binds arsenic ions, As(V) and As (III), in aqueous solutions. In this research, TtArsC enzyme adsorption onto hybrid polyethylene glycol-stabilized gold nanoparticles (AuNPs) was studied at different pH values as an innovative nanobiosystem for metal concentration monitoring. Characterizations were performed by UV/Vis and circular dichroism spectroscopies, TEM images and in terms of surface charge changes. The molecular interaction between arsenic ions and the TtArsC-AuNPs nanobiosystem was also monitored at all pH values considered by UV/Vis spectroscopy. Tests performed revealed high sensitivities and limits of detection equal to 10 ± 3 M−12 and 7.7 ± 0.3 M−12 for As(III) and As(V), respectively
Optical sensing properties of phthalocyanines thin films in array configuration and their application in VOCs detection.
No full textCODEN: 69FXZK CAN 143:50408 AN 2004:85899
The amphiphilic hydrophobin Vmh2 plays a key role in one step synthesis of hybrid protein-gold nanoparticles
No full textWe report a simple and original method to synthesize gold nanoparticles in which a fungal protein, the hydrophobin Vmh2 from Pleurotus ostreatus and dicarboxylic acid-terminated polyethylene-glycol (PEG) has been used as additional components in a one step process, leading to hybrid protein-metal nanoparticles (NPs). The nanoparticles have been characterized by ultra-violet/visible, infrared and X-ray photoelectron spectroscopies, dynamic light scattering and also by electron microscopy imaging. The results of these analytical techniques highlight nanometric sized, stable, hybrid complexes of about 12nm, with outer surface rich in functional chemical groups. Interaction with protein and antibodies has also been exploited
Correction: Flavin-adenine-dinucleotide gold complex nanoparticles: chemical modeling design, physico-chemical assessment and perspectives in nanomedicine
No full textCorrection for 'Flavin-adenine-dinucleotide gold complex nanoparticles: chemical modeling design, physico-chemical assessment and perspectives in nanomedicine' by Celia Arib et al., Nanoscale Adv., 2021, 3, 6144-6156, https://doi.org/10.1039/D1NA00444A
Development of gold-polymer hybrid nanovectors for pancreatic cancer therapy
No full textLa nanomédecine est l'un des domaines en plein essor qui présente de nouvelles techniques de diagnostic et de traitement du cancer, elle peut faire intervenir différents types de nanomatériaux. Notamment, les nanoparticules d'or (AuNPs), qui possèdent des propriétés physicochimiques et optiques uniques. Ces propriétés en font un outil intéressant pour la thérapie chimiothérapeutique ciblée, l'imagerie tumorale et la thérapie photothermique. L'objectif de cette thèse est de développer et d'optimiser plusieurs formulations de nanovecteurs, afin d'améliorer la délivrance d'agents thérapeutiques. La première étape a été de concevoir une nouvelle génération de nanovecteurs qui ont été synthétisés par complexation de biomolécules (enzymes; albumine de sérum bovin (BSA), Superoxyde dismutase de Manganèse (MnSOD), catalase (CAT)) au sel d'or. Dans une seconde partie, nous avons développé un nanovecteur organique basé sur la complexation d'un polymère, le polyéthylène glycol diacide (PEG-COOH) avec un cofacteur (FAD). Ce complexe sera un précurseur pour le développement d'un nanovecteur hybride. La FAD joue un rôle clé dans un large éventail de réactions d'oxydoréduction cellulaires, qui sont impliquées dans les mécanismes métaboliques. L'objectif final est de développer plusieurs formulations de flavine pour le traitement du cancer. Ces nanovecteurs ont été caractérisés par des techniques physico-chimiques, en parallèle d'études in vitro. Enfin dans la dernière partie, nous avons développé un nanovecteur hybride à partir de sel d'or, et de peptides de pénétration cellulaire (Neurofilament à chaîne légère (NFL), Transcription Transactivator (TAT) et Vimentin (VIM)). Ces peptides sont connus pour leur capacité à traverser la membrane cellulaire. La caractérisation de ces nanovecteurs a été réalisée par différentes techniques de spectroscopie, suivie d'études de stabilité, d'internalisation cellulaire et d'études in vitro. Les deux nanovecteurs peptidiques complexés avec des nanoparticules d'or et FAD-PEG ont été appliqués sur des études in vivo de cancer du pancréas et du foie. Le but de ces études était de voir l'effet thérapeutique des nanovecteurs et leur impact sur le système immunitaire et les éventuels effets secondaires qui peuvent être générés. Ces études ont montré que les les NFL-BIOT-PEG-AuNPs et PEG-FAD peuvent être des candidats intéressants pour le traitement du cancer.Nanomedicine is one of the growing fields that presents new techniques for diagnosis and treatment of cancer, it may involve different types of nanomaterials. Notably, gold nanoparticles (AuNPs), which possess unique physicochemical and optical properties. These properties make them an interesting tool for the targeted chemotherapeutic therapy, tumor imaging and photothermal therapy. The objective of this thesis is to develop and optimize several nanovector formulations, to improve the delivery of therapeutic agents. The first step was to design a new generation of nanovectors which were synthesized by complexation of biomolecules (enzymes ; Bovine Serum Albumin (BSA), Manganese Superoxide Dismutase (MnSOD), catalase (CAT)) to the gold salt. In the second part, we developed an organic nanovector based on the complexation of a polymer, polyethylene glycol diacid (PEG-COOH) with a cofactor (FAD). This complex will be a precursor for the development of a hybrid nanovector. FAD plays a key role in a wide range of cellular redox reactions, which are involved in metabolic mecanisms. The final goal is to develop several formulations of flavin for the cancer treatment. These nanovectors have been characterized by physicochemical techniques, in parallel of in vitro studies. Finally, in the last part, we developed a hybrid nanovector from gold salt, and cell penetration peptides (Light Chain Neurofilament (NFL), Transcription Transactivator (TAT) and Vimentin (VIM)). These peptides known for their ability to cross the cell membrane. The characterization of these nanovectors were performed by different spectroscopy techniques, followed by stability studies, cellular internalization and in vitro studies. Both peptide nanovectors complexed with gold nanoparticles and FAD-PEG were applied on pancreatic and liver cancer in vivo studies. The aim of these studies were to see therapeutic effect of the nanovectors and their impact on the immune system and the possible side effects that may be generated. These studies has shown that PEG-FAD and NFL-BIOT-PEG-AuNPs can be interesting cadidates for the treatment of cancer
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