Assemblage lipides/particules de polymère – conception et applications biomédicales

Conférence en universitéNational audienc

Interests of chitosan nanoparticles conically cross-linked with tripolyphosphate for biomedical applications

International audienceThe process of ionic gelation is one of the easiest ways to develop chitosan nanoparticles reported so far in the literature. Its success is mainly due to its one-shot synthesis, and to the mild environment required to produce the nanoparticles. The nanoparticle formation all along this process has been therefore thoroughly studied to lead to particles with a nanometric size, a narrow size distribution, and a spherical shape that are ideal for biomedical uses. The purpose of this review is to compile the biomedical applications that have been considered in the literature for these chitosan nanoparticles prepared by ionic gelation using tripolyphosphate as ionic agent. Their intrinsic biological properties such as non-toxicity, antimicrobial activity, mucoadhesivity and haemocompatibility are firstly discussed and compared to those of chitosan solutions. Then, the different bioactive species (drugs and biomacromolecules) incorporated in these chitosan nanoparticles, their maximal incorporation efficiency, their loading capacity, and their principal associated biomedical applications are presented

Toward an optimized treatment of intracellular bacterial infections: input of nanoparticulate drug delivery systems

International audienceIntracellular pathogenic bacteria can lead to some of the most life-threatening infections. By evolving a number of ingenious mechanisms, these bacteria have the ability to invade, colonize and survive in the host cells in active or latent forms over prolonged period of time. A variety of nanoparticulate systems have been developed to optimize the delivery of antibiotics. Main advantages of nanoparticulate systems as compared with free drugs are an efficient drug encapsulation, protection from inactivation, targeting infection sites and the possibility to deliver drugs by overcoming cellular barriers. Nevertheless, despite the great progresses in treating intracellular infections using nanoparticulate carriers, some challenges still remain, such as targeting cellular subcompartments with bacteria and delivering synergistic drug combinations. Engineered nanoparticles should allow controlling drug release both inside cells and within the extracellular space before reaching the target cells

A close collaboration of chitosan with lipid colloidal carriers for drug delivery applications

International audienc

Controlled Radical Polymerization of Acrylic Acid in Protic Media

International audienc

An overview of lipid membrane supported by colloidal particles

International audienc

Chitosan hydrogels for sustained drug delivery

International audienc

Lateral Organization of Lipid Membranes Induced by Amphiphilic Polymer Inclusions

International audienc

Elaboration of chitosan nanoparticles: Favorable impact of a mild thermal treatment to obtain finely divided, spherical, and colloidally stable objects

International audienceThe elaboration of chitosan (CS) nanoparticles via an ionic gelation process using sodium tripolyphosphate (TPP) as cross-linking agent was thoroughly studied in order to develop colloidally stable, spherical CS nanoparticles with a reproducible sub-micrometer size, and a narrow size distribution. To this end, the most relevant parameters involved in the synthesis such as CS chains concentration and molecular weight as well as ionic strength and pH of CS initial solutions were investigated and optimized. The physicochemical characterization of resulting CS nanoparticles was carried out in terms of size, size distribution, and surface charge by quasi-elastic light scattering (QELS), nanoparticle tracking analysis (NTA), and zeta potential measurements. Morphological characterization using classical and cryogenic transmission electron microscopy (TEM and cryo-TEM) was then performed revealing a high number of aggregates mixed to individualized nanoparticles with drop-like and irregular shapes. These limitations were overcome by applying a specific and optimized thermal treatment which appeared to significantly reduce the aggregate number, and to restructure the CS nanoparticles into highly spherical objects. Based on all these findings, reproducible, cationic (zeta potential = +37 +/- 5 mV), stable (at least 4 months at 20 degrees C), spherical, and mainly individualized CS nanoparticles of 100 +/- 30 nm (determined from cryo-TEM images) were obtained

First systematic MALDI/ESI Mass Spectrometry Comparison to Characterize Polystyrene Synthesized by Different Controlled Radical Polymerizations

International audienc