Poly-L-asparagine nanocapsules as anticancer drug delivery vehicles

This work presents for the first time the development of novel poly-L-asparagine (PASN) nanocapsules and the in vitro evaluation of their potential as anticancer drug delivery systems. The design of PASN nanocapsules was inspired by the well-known avidity of cancer cells for the amino acid L-asparagine together with the expected ability of this hydrophilic polymer to escape to the mononuclear phagocytic system. Besides, these nanocapsules have an oily reservoir, which enables the efficient encapsulation of lipophilic drugs. PASN nanocapsules were obtained by an emulsification-polymer layer deposition process, which involves using a cationic surfactant as a bridge for the interaction of PASN with the lipid core. PASN nanocapsules showed sizes of around 170-200 nm and negative zeta potential values (around -20 mV to -40 mV). The model anticancer drug docetaxel was efficiently encapsulated (around 75%) and retained within the nanocapsule's structure upon dilution in a simulated physiological medium. Moreover, these nanocapsules exhibited the ability to interact with the NCI-H460 human cancer cells and to enhance the cellular toxicity of the anticancer drug. All these features together with their adequate stability profile render these nanocapsules a new attractive platform for anticancer intracellular drug delivery.