Carboxymethyl chitosan/ionic liquid imidazolium-based nanoparticles as nanocarriers for zinc phthalocyanine and its photodynamic activity

Abstract

New nanocarriers have contributed to develop the so-called third-generation photosensitizers for use in the photodynamic therapy (PDT). In this paper, nanoparticles based on carboxymethyl chitosan (CMC) and a monocationic ionic liquid imidazolium-based (IL) (1-dodecyl-3-methylimidazolium bromide, C12MIMBr), loaded with photosensitizer zinc phthalocyanine (ZnPc) was developed for application in PDT. The CMC/IL@ZnPc nanoparticles were characterized by their physicochemical properties, photodynamic activity and drug release profile, and while their performances were compared with those containing conventional surfactants. The polymeric nanoparticles display a nanometric hydrodynamic radius, low polydispersity index, negative zeta potential, high drug loading and encapsulation efficiencies higher than 98%. Moreover, CMC/IL@ZnPc nanoparticles have the ability to produce cytotoxic singlet oxygen (1O2) and the values of singlet oxygen quantum yields (ΦΔ) are appropriated for application in PDT. In vitro release kinetic of ZnPc from nanoparticles exhibited a sustained release profile controlled by diffusion, without burst effect. Our findings highlight that CMC/IL-based nanoparticles have potential to be employed as nanocarriers for hydrophobic photosensitizers in PDT.