Search results for "nanoparticle"

Nitroarene hydrogenation catalysts based on Pd nanoparticles glued with PDA on inorganic supports: Multivariate Curve Resolution as an useful tool to…

2021

[EN] Two green catalysts based on Pd(0) nanoparticles (Pd NPs) anchored through PDA on porous silica and magnetite have been synthesized using a generalized simple and reproducible "two-step" methodology. Both catalysts were tested for a model reaction, the hydrogenation of 4-nitrophenol using NaBH4 as the hydrogenating agent, and especially good activity has been achieved in the case of the catalysts containing magnetite as inorganic core (Pd NPs-PDA@Fe3O4). We analyzed the effect associated with the catalyst separation method (centrifugation or magnetically) that affect to the distribution and aggregation degree of the Pd NPs. In addition, we also correlate the final catalyst morphology w…

Ciprofloxacin releasing gellan gum/polydopamine based hydrogels with near infrared activated photothermal properties.

2021

Abstract In this work, with the aim to obtain a wound dressing hydrogel, an amine derivative of gellan gum was crosslinked in the presence of 4arm-polyethylenglycole-vinylsulfone. Through this easy and reproducible chemical procedure, a hydrogel with advanced elastic properties and hydrolytic resistance under physiological conditions was obtained. The incorporation of different quantities of polydopamine in the gelling solutions allows to obtain different hydrogels with marked photothermal properties when irradiated with a laser in the near infrared at 810 nm. The organic nanoparticles, reacting with the amino groups of the polysaccharide derivative, contribute to increase the storage modul…

Gold nanostars coated with neutral and charged polyethylene glycols: A comparative study of in-vitro biocompatibility and of their interaction with S…

2015

Gold nanostars (GNS) have been coated with four different polyethylene glycols (PEGs) equipped with a -SH function for grafting on the gold surface. These PEGs have different chain lengths with average MW = 2000, 3000, 5000 and average number of -O-CH2-CH2 - units 44, 66, and 111, respectively. Two are neutral and two are terminated with -COOH and -NH2 functions, thus bearing negative and positive charges at physiological pH, thanks to the formation of carboxylate and ammonium groups. The negative charge of the GNS coated with PEG carboxylate has also been exploited to further coat the GNS with the PAH (polyallylamine hydrochloride) cationic polymer. Vitality tests have been carried out on …

Mucoadhesive PEGylated inulin-based self-assembling nanoparticles: In vitro and ex vivo transcorneal permeation enhancement of corticosteroids

2019

Abstract As transcorneal drug delivery is still a challenge, the scope of the present study was to prepare useful nanosystems able to enhance transcorneal permeation/penetration of drugs. Moreover, this work aims to evaluate the effectiveness of inulin-based nanosystems in the specific field of ocular drug delivery and the effect of PEG chains to promote mucoadhesion, stability and transcorneal penetration/permeation enhancer effect of self-assembling nanoparticles in vitro (transwell systems and HCE) and ex vivo (Franz cells and bovine cornea). In particular, inulin was chosen as the starting natural polysaccharide polymer to design a novel amphiphilic derivative named INU-EDA-RA-PEG capab…

Excess free energy of nanoparticles in a polymer brush

2008

Abstract We present an efficient method for direct determination of the excess free energy Δ F of a nanoparticle inserted into a polymer brush. In contrast to Widom's insertion method, the present approach can be efficiently implemented by Monte Carlo or Molecular Dynamics methods also in a dense environment. In the present investigation the method is used to determine the free energy penalty Δ F ( R , D ) for placing a spherical particle with an arbitrary radius R at different positions D between the grafting plane and the brush surface. Deep inside the brush, or for dense brushes, one finds Δ F  ∝  R 3 whereas for shallow nanoclusions Δ F  ∝  R 2 , regardless of the particle interaction (…

SURFACE MODIFICATION OF EAA WITH FUNCTIONALIZED SILICA NANOPARTICLES

2009

Polymeric nanoparticles as a new generation of anti-oxidant carriers

2016

In recent years, polymeric nanoparticles have been the object of growing scientific interest, especially as drug carriers. In this work, PEO-PPO-PEO (F127, commercial Pluronic F127®) nanoparticles has been used as carriers for naturally occurring anti-oxidant, such as quercetin (Q).

Composite nanoparticles based on hyaluronic acid chemically cross-linked with alpha,beta-polyaspartylhydrazide.

2007

In this paper, new composite nanoparticles based on hyaluronic acid (HA) chemically cross-linked with alpha,beta polyaspartylhydrazide (PAHy) were prepared by the use of a reversed-phase microemulsion technique. HA-PAHy nanoparticles were characterized by FT-IR spectroscopy, confirming the occurrence of the chemical cross-linking, dimensional analysis, and transmission electron micrography, showing a sub-micrometer size and spherical shape. Zeta potential measurements demonstrated the presence of HA on the nanoparticle surface. A remarkable affinity of the obtained nanoparticles toward aqueous media that simulate some biological fluids was found. Stability studies showed the absence of chem…

Protein-Based Nanoparticles for the Delivery of Enzymes with Antibacterial Activity.

2018

Proteins represent a versatile biopolymer material for the preparation of nanoparticles due to their biocompatibility, biodegradability, and low immunogenicity. This study presents a protein-based nanoparticle system consisting of high surface PEGylated lysozyme polyethylene glycol-modified lysozyme (LYZmPEG ). This protein modification leads to a solubility switch, which allows a nanoparticle preparation using a mild double emulsion method without the need of surfactants. The method allows the encapsulation of large hydrophilic payloads inside of the protein-based nanoparticle system. Native lysozyme (LYZ) was chosen as payload because of its innate activity as natural antibiotic. The mild…

PEGYLATED POLYASPARTAMIDE–POLYLACTIDE BASED NANOPARTICLES PENETRATING CYSTIC FIBROSIS ARTIFICIAL MUCUS

2016

Here, the preparation of mucus-penetrating nanoparticles for pulmonary administration of ibuprofen in patients with cystic fibrosis is described. A fluorescent derivative of α,β-poly(N-2-hydroxyethyl)-D,L-aspartamide is synthesized by derivatization with rhodamine, polylactide, and poly(ethylene glycol), to obtain polyaspartamide− polylactide derivatives with different degrees of pegylation. Starting from these copolymers, fluorescent nanoparticles with different poly(ethylene glycol) content, empty and loaded with ibuprofen, showed spherical shape, colloidal size, slightly negative ζ potential, and biocompatibility toward human bronchial epithelial cells. The high surface poly(ethylene gly…