Nanoparticle formation from poly(acrylic acid) and oppositely charged peptides

Cationic peptides self assemble upon interacting with sodium salt of oppositely charged polymer, poly(acrylic acid), PAA, giving rise to water-soluble nanoparticles at very low concentration (0.1 mM of PAA). The morphology of these kinds of nanoparticles is mainly governed by the composition of the complexes, which can be expressed as Z+/−, i.e., the ratio of positively charged units to the concentration of anionic units of the polymers present in the system. In the present study, at lower Z+/−, the particles are elongated in shape but adopt spherical shape of 75-100 nm in diameter at higher Z+/− values. We propose that the nanoparticles containing cationic peptides obtained by this methodology can serve as delivery system to enhance the antinociception effect of the chimeric peptide with previously administered doses.