Ethylcellulose nanoparticles prepared from nano-emulsion templates as new folate binding haemocompatible platforms.

Ethylcellulose is a biocompatible polymer attracting increasing interest for biomedical applications. In the present work, the formation of folate-ethylcellulose nanoparticle complexes from nano-emulsion templates prepared by a low-energy approach, using aqueous components suitable for biomedical applications has been investigated. The composition of the aqueous component is shown to be crucial for the formation of stable nano-emulsions and influences the zeta potential values. The ethylcellulose nanoparticles with mean sizes around 100 nm were obtained from the nano-emulsions by solvent evaporation and showed positive zeta potential values above +20 mV due to the presence of the cationic surfactant. The nanoparticles were successfully complexed with folate, as evidenced by both particle size and zeta potential measurements. The complexes prepared with HEPES buffered glucose solution showed excellent haemocompatibility, which make them promising for parenteral therapeutic applications and also for those in which easy access to systemic circulation may occur, like in lungs.

Quantifying the bioadhesive properties of surface-modified polyurethane-urea nanoparticles in the vascular network.

Nanomedicine research is currently requiring new standard methods to quantify the biocompatibility and bioadhesivity of emerging biomaterials designed to be used in contact with blood or soft tissues. In this study, we used biotinylated polyurethane-urea nanoparticles as a model to examine the applicabitility of an adapted hemagglutination assay to quantify the bioadhesive potential of these nanoparticles to red blood cells and, in turn, to extrapolate this data to vascular endothelial cells. We demonstrated that biotinylated nanoparticles adsorb to human erythrocytes and preferentially gather in erythrocyte contact areas. Moreover, these nanoparticles promoted a higher percentage of pig and human erythrocyte agglutination than naked polyurethane-urea nanoparticles in a biotin concentration-dependent manner. Conversely, pegylated nanoparticles were used as a negative control of the technique thus showing decreasing hemagglutination values as compared to naked nanoparticles until a minimum threshold. Furthermore, hemagglutination assay demonstrated an excellent positive correlation with bioadhesion quantification in human endothelial cells and the endothelial layer of pig aorta thus validating the hemagglutination assay described here as a useful method for predicting nanoparticle bioadhesivity to vascular endothelium. Therefore, the methodology described here is a versatile and straightforward method that allows evaluating the bioadhesive features of surface-modified polyurethane-urea nanoparticles in contact with blood and the vascular network and appears as a powerful tool to better design any drug delivery systems or implantable devices for biomedical applications.

Polyurethane and polyurea nanoparticles based on polyoxyethylene castor oil derivative surfactant suitable for endovascular applications.

The design of new, safe and effective nanotherapeutic systems is an important challenge for the researchers in the nanotechnology area. This study describes the formation of biocompatible polyurethane and polyurea nanoparticles based on polyoxyethylene castor oil derivative surfactant formed from O/W nano-emulsions by polymerization at the droplet interfaces in systems composed by aqueous solution/Kolliphor(®) ELP/medium chain triglyceride suitable for intravenous administration. Initial nano-emulsions incorporating highly hydrophilic materials were prepared by the phase inversion composition (PIC) method. After polymerization, nanoparticles with a small particle diameter (25-55 nm) and low polydispersity index were obtained. Parameters such as concentration of monomer, O/S weight ratio as well as the polymerization temperature were crucial to achieve a correct formation of these nanoparticles. Moreover, FT-IR studies showed the full conversion of the monomer to polyurethane and polyurea polymers. Likewise the involvement of the surfactant in the polymerization process through their nucleophilic groups to form the polymeric matrix was demonstrated. This could mean a first step in the development of biocompatible systems formulated with polyoxyethylene castor oil derivative surfactants. In addition, haemolysis and cell viability assays evidenced the good biocompatibility of KELP polyurethane and polyurea nanoparticles thus indicating the potential of these nanosystems as promising drug carriers.

Formation of Pegylated polyurethane and Lysine-coated polyurea nanoparticles obtained from O/W nano-emulsions.

The present work describes the formation of Pegylated polyurethane and Lysine-coated polyurea nanoparticles obtained from O/W nano-emulsions via an interfacial polycondensation process in the aqueous solution/polysorbate 80/diisocyanate/medium chain triglyceride systems. The initial nano-emulsions were prepared using the phase inversion composition (PIC) method. Dynamic light scattering studies revealed the changes in the particle size occurring during the process of nanoparticle formation. Well-defined polymeric nanoparticles with a small particle diameter (below 80 nm) and low polydispersity index were obtained using a highly hydrophilic component (polyethylene glycol or lysine) and an aliphatic diisocyante monomer. FT-IR and AFM studies showed that the polymeric matrix of nanoparticles was built by copolymers derived from reaction between the diisocyanate and the hydroxyl groups of both nonionic surfactant and the highly hydrophilic component. Pegylated-polyurethane and lysine-coated polyurea nanoparticles designed in this study are promising tools for future applications in biomedical sciences.