Fabrication of chitosan based nanocomposite with legumain sensitive properties using charge driven self-assembly strategy.

Chitosan (CS) based nanoparticles (NPs) have several advantages in delivering drugs. They are usually prepared in a micro-emulsion solvent system but this route can leave significant levels of potentially harmful organic solvent residue in the NPs. In this study, we prepared CS based nanocomposites using charge driven self-assembly in an aqueous buffer, thus avoiding the use of organic solvents. Doxorubicin (DOX) was covalently attached to positive charged CS with a legumain substrate peptide to confer targeted drug release property, since legumain is often overexpressed in tumors or tumor associated micro environments. This DOX prodrug solution interacted with negative charged methoxyl poly (ethylene glycol)-block-poly (glutamic acid) copolymer (PEG-PGA) in an aqueous buffer forming nanocomposite with a regular morphology. The particle size and zeta potential of these NPs was regulated by the addition of different PEG-PGA concentrations into the DOX prodrug solution. Due to its potential for legumain triggered release, this DOX NP exhibited enhanced cytotoxicity against choroidal melanoma cell line (Mum-2C) and reduced cytotoxicity on normal human corneal epithelial cells (HCEC), suggesting a good potential for enhanced targeted delivery of chemotherapeutic agents. A chitosan based nanocomposite with legumain sensitive properties are rapidly controllable prepared in aqueous buffer by charge driven self-assembly strategy, without using micro-emulsion solvent system and cross-linking agents.