P. Veratti

Characterization of lysosome-destabilizing DOPE/PLGA nanoparticles designed for cytoplasmic drug release.

Polymeric nanoparticles (NPs) offer a promising approach for therapeutic intracellular delivery of proteins, conventionally hampered by short half-lives, instability and immunogenicity. Remarkably, NPs uptake occurs via endocytic internalization leading to NPs contents release within lysosomes. To overcome lysosomal degradation and achieve NPs and/or loaded proteins release into cytosol, we propose the formulation of hybrid NPs by adding 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) as pH sensitive component in the formulation of poly-lactide-co-glycolide (PLGA) NPs. Hybrid NPs, featured by different DOPE/PLGA ratios, were characterized in terms of structure, stability and lipid organization within the polymeric matrix. Experiments on NIH cells and rat primary neuronal cultures highlighted the safety profile of hybrid NPs. Moreover, after internalization, NPs are able to transiently destabilize the integrity of lysosomes in which they are taken up, speeding their escape and favoring cytoplasmatic localization. Thus, these DOPE/PLGA-NPs configure themselves as promising carriers for intracellular protein delivery.

Exploiting Bacterial Pathways for BBB Crossing with PLGA Nanoparticles Modified with a Mutated Form of Diphtheria Toxin (CRM197): In Vivo Experiments

Drugs can be targeted to the brain using polymeric nanoparticles (NPs) engineered on their surface with ligands able to allow crossing of the blood-brain barrier (BBB). This article aims to investigate the BBB crossing efficiency of polymeric poly lactide-co-glycolide (PLGA) NPs modified with a mutated form of diphtheria toxin (CRM197) in comparison with the results previously obtained using PLGA NPs modified with a glycopeptide (g7-NPs). Different kinds of NPs, covalently coupled PLGA with different fluorescent probes (DY405, rhodamine-B base and DY675) and different ligands (g7 and CRM197) were tested in vivo to assess their behavior and trafficking. The results highlighted the possibility to distinguish the different kinds of simultaneously administered NPs and to emphasize that CRM-197 modified NPs and g7-NPs can cross the BBB at a similar extent. The analysis of BBB crossing and of the neuronal tropism of CRM197 modified NPs, along with their BBB crossing pathways were also developed. In vivo pharmacological studies performed on CRM197 engineered NPs, loaded with loperamide, underlined their ability as drug carriers to the CNS.

AFM/TEM Complementary Structural Analysis of Surface-Functionalized Nanoparticles

In the field of nanomedicine, the characterization of functionalized drug delivery systems, introduced on market as efficacious and selective therapeutics, represents a pivotal aspect of great importance. In particular, the morphology of polymeric nanoparticles, the most studied nanocarriers, is frequently assessed by transmission electron microscopy (TEM). Despite of TEM high resolution and versatility, this technology is frequently hampered by both the complicated procedure for sample preparation and the operative condition of analysis. Considering the scanning probe microscopies, atomic force microscopy (AFM) represents an extraordinary tool for the detailed characterization of submicron-size structure as the surface functionalization at the atomic scale. In this paper we discussed the advantage and limits of these microscopies applied to the characterization of PLGA nanoparticles functionalized with three different kinds of ligands (carbohydrate ligand, an antibody and quantum dots crystals) intentionally designed, created and tailored with specific physico-chemical properties to meet the needs of specific applications (targeting or imaging).