Search results for "nanoparticle"

PHEA-graft-polybutylmethacrylate copolymer microparticles for delivery of hydrophobic drugs.

2012

Abstract Polymeric microparticles encapsulating two model hydrophobic drugs, beclomethasone dipropionate (BDP) and flutamide (FLU) were prepared by using the high pressure homogenization-solvent evaporation method starting from a oil-in-water emulsion. For the preparation of polymeric microparticles a α,β-poly(N-2-hydroxyethyl)- d , l -aspartamide (PHEA) graft copolymer with comb like structure was properly synthesized via grafting from atom transfer radical polymerization (ATRP) technique, by using two subsequent synthetic steps. In the first step a polymeric multifunctional macroinitiator was obtained by the conjugation of a proper number of 2-bromoisobutyryl bromide (BIB) residues to the…

Detoxifying antitumoral drugs via nanoconjugation: the case of gold nanoparticles and cisplatin

2021

Nanoparticles (NPs) have emerged as a potential tool to improve cancer treatment. Among the proposed uses in imaging and therapy, their use as a drug delivery scaffold has been extensively highlighted. However, there are still some controversial points which need a deeper understanding before clinical application can occur. Here the use of gold nanoparticles (AuNPs) to detoxify the antitumoral agent cisplatin, linked to a nanoparticle via a pH-sensitive coordination bond for endosomal release, is presented. The NP conjugate design has important effects on pharmacokinetics, conjugate evolution and biodistribution and results in an absence of observed toxicity. Besides, AuNPs present unique o…

Interactions of silica nanoparticles with lung epithelial cells and the association to flotillins

2012

Amorphous silica nanoparticles (aSNPs) gain increasing popularity for industrial and therapeutic claims. The lung with its surface area of 100-140 m(2) displays an ideal target for therapeutic approaches, but it represents also a serious area of attack for harmful nanomaterials. The exact nature of the cytotoxic effects of NPs is still unknown. Furthermore, cellular pathways and the destiny of internalized NPs are still poorly understood. Therefore, we examined the cytotoxicity (MTS, LDH) and inflammatory responses (IL-8) for different-sized aSNPs (30, 70, 300 nm) on our lung epithelial cells line NCI H441 and endothelial cell line ISO-HAS-1. Additionally, colocalization studies have been c…

Study of the dynamics of biomolecules by high speed atomic force microscopy and surface enhanced Raman spectroscopy

2015

This thesis focuses on the coupling of High–Speed Atomic Force Microscopy (HS-AFM) and Surface Enhanced Raman Spectroscopy (SERS) for biomolecule analysis. We have designed a fabrication protocol to manufacture “SERS-active” substrates. The efficacy of gold, silver and gold-silver bimetallic crystalline nanoparticle substrates were evaluated. We have investigated the impact of optical and morphological features of the substrates on Raman signal intensity by analyzing well-known samples such as bipyridine ethylene and methylene blue molecules. We took an interest in three distinct biological problematics with HS-AFM and SERS analyses. First, we have detected the chemical signature of cytochr…

Thermal Evolution of Titania Nanostructured Powders Obtained from Reverse Micelle Method

2012

Micro/nanostructured thin films : synthesis by ALD of composites associating TiO2 inverse opals and gold nanoparticles for photocatalysis applications

2021

The aim of this work was to improve the photocatalytic properties of titanium dioxide (TiO2) thin films, a semiconductor that is widely used for photocatalysis applications, particularly for the treatment of polluted water. For this purpose, two complementary approaches were studied: increasing the surface area available for photocalatytic reactions and coupling between TiO2 and gold nanoparticles.. For the first approach, TiO2 thin films with different morphological structures were fabricated by Atomic Layer Deposition: dense and porous flat films, and inverse opals films.In order to evaluate photocatalytic activity of the different films, the degradation of methylene blue in aqueous solut…

Hydrothermal Synthesis of Ionic Liquid [Bmim]OH-Modified TiO2 Nanoparticles with Enhanced Photocatalytic Activity under Visible Light

2010

TiO(2) nanocomposites modified with the ionic liquid [Bmim]OH are synthesized by a hydrothermal procedure. X-ray diffraction, Zeta-potential measurement, TEM, thermogravimetric analysis, photoluminescence, UV/Vis, FTIR, and X-ray photoelectron spectroscopy are used to characterize the TiO(2) nanocomposites. The TiO(2) nanocomposites consist of pure anatase particles of about 10 nm. The modification of [Bmim]OH on the surface of the TiO(2) particles extends the TiO(2) absorption edge to the visible-light region. The electrochemical redox potentials indicated that the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of [Bmim]OH match well with the valen…

Synthesis of Mesoporous Supraparticles on Superamphiphobic Surfaces

2015

A method for mesoporous supraparticle synthesis on superamphiphobic surfaces is designed. Therefore, supraparticles assembled with nanoparticles are synthesized by the evaporation of nanoparticle dispersion drops on the superamphiphobic surface. For synthesis, no further purification is required and no organic solvents are wasted. Moreover, by changing the conditions such as drop size and concentration, supraparticles of different sizes, compositions, and architectures are fabricated.

High-Performance TiO2 Nanoparticle/DOPA-Polymer Composites

2014

Many natural materials are complex composites whose mechanical properties are often outstanding considering the weak constituents from which they are assembled. Nacre, made of inorganic (CaCO 3 ) and organic constituents, is a textbook example because of its strength and toughness, which are related to its hierarchical structure and its well-defi ned organic–inorganic interface. Emulating the construction principles of nacre using simple inorganic materials and polymers is essential for understanding how chemical composition and structure determine biomaterial functions. A hard multilayered nanocomposite is assembled based on alternating layers of TiO 2 nanoparticles and a 3-hydroxytyramine…

Nano into Micro Formulations of Tobramycin for the Treatment of Pseudomonas aeruginosa Infections in Cystic Fibrosis.

2017

Here, nano into micro formulations (NiMs) of tobramycin for the treatment of Pseudomonas aeruginosa airway infections in cystic fibrosis (CF) are described. NiMs were produced by spray drying a solution containing polymers or sugars and a nanometric polyanion–tobramcyin complex (PTC), able to achieve a prolonged antibiotic release. NiMs properties were compared to TOBIPodhaler(Novartis), the only one commercially available dry powder inhalatory formulation based on porous microparticles. Produced NiMs showed adequate characteristics for pulmonary administration, as spherical shape, micrometric size, and high cytocompatibility toward human bronchial epithelial cells. Contrarily to TOBIPodhal…