In vitro toxicity studies of biodegradable, polyelectrolyte nanocapsules

Abstract

BackgroundToxicity of nanomaterials is one of the most important factors limiting their medical application. Evaluation of in vitro nanotoxicity allows for the identification and elimination of most of the toxic materials prior to animal testing. The current knowledge of the possible side effects of biodegradable nanomaterials, such as liposomes and polymeric organic nanoparticles, is limited. Previously, we developed a potential drug delivery system in the form of nanocapsules with polyelectrolyte, biodegradable shells consisting of poly-l-lysine and poly-l-glutamic acid (PGA), formed by the layer-by-layer adsorption technique.MethodsHemolysis assay, viability tests, flow cytometry analysis of vascular cell adhesion molecule-1 expression on endothelium, analysis of nitric oxide production, measurement of intracellular reactive oxygen species levels, detection of antioxidant enzyme activity, and analysis of DNA damage with comet assay were performed to study the in vitro toxicity of nanocapsules.ResultsIn this work, we present the results of an in vitro analysis of toxicity of five-layer positively charged poly-l-lysine–terminated nanocapsules (NC5), six-layer negatively charged PGA-terminated nanocapsules (NC6) and five-layer PEGylated nanocapsules (NC5-PEG). PGA and polyethylene glycol (PEG) were used as two different “stealth” polymers. Of all the polyelectrolyte nanocapsules tested for blood compatibility, only cationic NC5 showed acute toxicity toward blood cells, expressed as hemolysis and aggregation. Neither NC6 nor NC5-PEG had proinflammatory activity evaluated through changes in the expression of NF-κB–dependent genes, iNOS and vascular cell adhesion molecule-1, induced oxidative stress, or promoted DNA damage in various cells.ConclusionOur studies clearly indicate that PGA-coated (negatively charged) and PEGylated polyelectrolyte nanocapsules do not show in vitro toxicity, and their potential as a drug delivery system may be safely studied in vivo.

<p>In vivo Studies on Pharmacokinetics, Toxicity and Immunogenicity of Polyelectrolyte Nanocapsules Functionalized with Two Different Polymers: Poly-L-Glutamic Acid or PEG</p>

“…Therefore, their application might limit systemic side effects of enclosed therapeutic while maintaining their medical effectiveness. We also performed detailed in vitro toxicity analysis of the nanocapsules functionalized with PGA or PEG and confirmed the lack of deleterious effects towards cultured cells 21. Here, we present the results of in vivo evaluation of nanocapsules with an external layer composed of PGA (PGA-terminated nanocapsules, NC-PGA) or with an external layer composed of the copolymer of poly- l -lysine and polyethylene glycol (PEG-terminated nanocapsules, NC-PEG).…”

“…The following polyelectrolyte nanocarriers were synthesized by the encapsulation of nanoemulsion droplets in polyelectrolyte multilayer shell: NC-PGA (PGA-terminated six-layer polyelectrolyte nanocapsules), NC-PEG (PEG-terminated seven-layer polyelectrolyte nanocapsules) for toxicity analyses and NC-PGA-RhB (fluorescently labeled PGA-terminated six-layer polyelectrolyte nanocapsules), NC-PEG-RhB (fluorescently labeled PEG-terminated seven-layer polyelectrolyte nanocapsules) for pharmacokinetic and biodistribution analyses. This method has been described in detail in our previous papers 21. Briefly, nanoemulsion droplets were formed by dispersing 0.1 mL of oil phase (34 mg/mL AOT dissolved in chloroform) into 200 mL aqueous polycation solution (0.1 mg/mL in 15 mM NaCl).…”

“…The stability of nanocapsules in serum was determined previously 24. Contamination of nanocapsules with lipopolysaccharide (LPS) was excluded with a method based on the detection of NO (nitrate oxide) produced by murine primary endothelial cells and macrophages in response to nanocapsules and cytokines 21…”

<p>Analysis of toxicity and anticancer activity of micelles of sodium alginate-curcumin</p>

“…DNA damage in bone marrow-derived cells (1×10 5 cells/100 µL of PBS) was assessed by comet assay, according to the previously described procedure 19. Fifty cells were randomly selected from two slides per sample and percentage of DNA in the comet tail (% DNA damage) was determined for each cell using epifluorescence microscope (Olympus IX-50, Olympus Corporation, Tokyo, Japan) with CCD camera and COMET ASSAY 2.9 software (Comet Plus, Theta System GmbH, Germany).…”

Polymeric Core-Shell Nanoparticles Prepared by Spontaneous Emulsification Solvent Evaporation and Functionalized by the Layer-by-Layer Method

“…Presently, polyethylene glycol (PEG) is the polymer most often used for nanomaterial functionalization. Alternative strategies replacing PEG with poly-amino acids, e.g., poly-L-glutamic acid (PGA) has been also implemented lately [9][10][11]. One of the powerful methods of surface modification is the sequential adsorption of charged nano-objects called the layer-by-layer (LbL) method [11][12][13][14].…”