Poly(lipoic acid)-based nanoparticles as a new therapeutic tool for delivering active molecules.

Pluronic-coated polylipoic acid-based nanoparticles (F127@PLA-NPs) have great potential as biodegradable nanovectors for delivering active molecules to different organs in complex diseases. In this study we describe the in vivo biodistribution, safety and ability to deliver molecules of F127@PLA-NPs in healthy rats following intravenous administration. Adult rats were injected with 10 mg/kg of rhodamine B-labeled F127@PLA-NPs, and NPs fluorescence and MFI rate were measured by confocal microscopy in whole collected organs. The NPs accumulation rate was maximal in the heart, compared to the other organs. At the cellular level, myocytes and kidney tubular cells showed the highest NPs uptake. Neither histopathological lesion nor thrombogenicity were observed after NPs injection. Finally, F127@PLA-NPs were tested in vitro as miRNAs delivery nanosystem, and they showed good ability in targeting cardiomyocytes. These results demonstrated that our F127@PLA-NPs constitute a biological, minimally invasive and safe delivery tool targeting organs and cells, such as heart and kidney.

Nanoparticles Based on Cross-Linked Poly(Lipoic Acid) Protect Macrophages and Cardiomyocytes from Oxidative Stress and Ischemia Reperfusion Injury.

The control of radical damage and oxidative stress, phenomena involved in a large number of human pathologies, is a major pharmaceutical and medical goal. We here show that two biocompatible formulations of Pluronic-stabilized, poly (lipoic acid)-based nanoparticles (NP) effectively antagonized the formation of radicals and reactive oxygen species (ROS). These NPs, not only intrinsically scavenged radicals in a-cellular DPPH/ABTS assays, but also inhibited the overproduction of ROS induced by tert-Butyl hydroperoxide (t-BHP) in tumor cells (HeLa), human macrophages and neonatal rat ventricular myocytes (NRVMs). NPs were captured by macrophages and cardiomyocytes much more effectively as compared to HeLa cells and non-phagocytic leukocytes, eventually undergoing intracellular disassembly. Notably, NPs decreased the mitochondrial ROS generation induced by simulated Ischemia/Reperfusion Injury (IRI) in isolated cardiomyocytes. NPs also prevented IRI-triggered cardiomyocyte necrosis, mitochondrial dysfunction, and alterations of contraction-related intracellular Ca2+ waves. Hence, NPs appear to be an effective and cardiomyocyte-selective drug to protect against damages induced by post-ischemic reperfusion.

Hydrolytic cleavage of nerve agent simulants by gold nanozymes.

Although banned by the Chemical Weapons Convention, organophosphorus nerve agents are still available and have been used in regional wars, terroristic attacks or for other crtaiminal purposes. Their degradation is of primary importance for the severe toxicity of these compounds. Here we report that gold nanoparticles passivated with thiolated molecules bearing 1,3,7-triazacyclononane and 1,3,7,10-tetraazacyclododecane ligands efficiently hydrolyze nerve agents simulants p-nitrophenyl diphenyl phosphate and methylparaoxon as transition metal complexes at 25 °C and pH 8 with half-lives of the order of a few minutes. Mechanistically, these catalysts show an enzyme-like behavior, hence they constitute an example of nanozymes. The catalytic site appears to involve a single metal ion and its recognition of the substrates is driven mostly by hydrophobic interactions. The ease of preparation and the mild conditions at which they operate, make these nanozymes appealing catalysts for the detoxification after contamination with organophosphorus nerve agents, particularly those poorly soluble in water.

Poly(lipoic acid)-Based Nanoparticles as Self-Organized, Biocompatible, and Corona-Free Nanovectors.

Herein we present an innovative approach to produce biocompatible, degradable, and stealth polymeric nanoparticles based on poly(lipoic acid), stabilized by a PEG-ended surfactant. Taking advantage of the well-known thiol-induced polymerization of lipoic acid, a universal and nontoxic nanovector consisted of a solid cross-linked polymeric matrix of lipoic acid monomers was prepared and loaded with active species with a one-step protocol. The biological studies demonstrated a high stability in biological media, the virtual absence of "protein" corona in biological fluids, the absence of acute toxicity in vitro and in vivo, complete clearance from the organism, and a relevant preference for short-term accumulation in the heart. All these features make these nanoparticles candidates as a promising tool for nanomedicine.

Specific and nondisruptive interaction of guanidium-functionalized gold nanoparticles with neutral phospholipid bilayers.

Understanding and controlling the interaction between nanoparticles and biological entities is fundamental to the development of nanomedicine applications. In particular, the possibility to realize nanoparticles capable of directly targeting neutral lipid membranes would be advantageous to numerous applications aiming at delivering nanoparticles and their cargos into cells and biological vesicles. Here, we use experimental and computational methodologies to analyze the interaction between liposomes and gold nanoparticles (AuNPs) featuring cationic headgroups in their protecting monolayer. We find that in contrast to nanoparticles decorated with other positively charged headgroups, guanidinium-coated AuNPs can bind to neutral phosphatidylcholine liposomes, inducing nondisruptive membrane permeabilization. Atomistic molecular simulations reveal that this ability is due to the multivalent H-bonding interaction between the phosphate residues of the liposome's phospholipids and the guanidinium groups. Our results demonstrate that the peculiar properties of arginine magic, an effect responsible for the membranotropic properties of some naturally occurring peptides, are also displayed by guanidinium-bearing functionalized AuNPs.

Multifunctional, CD44v6-Targeted ORMOSIL Nanoparticles Enhance Drugs Toxicity in Cancer Cells.

Drug-loaded, PEGylated, organic-modified silica (ORMOSIL) nanoparticles prepared by microemulsion condensation of vinyltriethoxysilane (VTES) were investigated as potential nanovectors for cancer therapy. To target cancer stem cells, anti-CD44v6 antibody and hyaluronic acid (HA) were conjugated to amine-functionalized PEGylated ORMOSIL nanoparticles through thiol-maleimide and amide coupling chemistries, respectively. Specific binding and uptake of conjugated nanoparticles were studied on cells overexpressing the CD44v6 receptor. Cytotoxicity was subsequently evaluated in the same cells after the uptake of the nanoparticles. Internalization of nanocarriers loaded with the anticancer drug 3N-cyclopropylmethyl-7-phenyl-pyrrolo- quinolinone (MG2477) into cells resulted in a substantial increase of the cytotoxicity with respect to the free formulation. Targeting with anti-CD44v6 antibodies or HA yielded nanoparticles with similar effectiveness, in their optimized formulation.