On-demand release of encapsulated ZnO nanoparticles and chemotherapeutics for drug delivery applications

Nanomedicines offer high promise for the treatment of various diseases, and numerous novel approaches using nanomaterials have been developed over the years. In this report, we introduce a new strategy utilizing ZnO nanoparticles (nZnO) to trigger the rapid release of lipid-encapsulated therapeutics upon photo-irradiation with UV light (365 nm). In vitro studies demonstrate that encapsulation of nZnO effectively eliminates the cytotoxicity of nZnO, but this can be re-established upon release from the lipid coating. Using 5(6)-carboxyfluorescein as a model for hydrophilic drug loading, we show the ability to co-load drugs with nZnO into liposomes. Kinetic studies reveal the ability to release the majority of the dye within 60 minutes post-photo-irradiation and provide insights into factors that impact release kinetics. To further explore this, Jurkat T cell leukemia and T47D breast cancer cells were treated with co-encapsulated nZnO and the hydrophobic cancer drug paclitaxel. These studies revealed enhanced toxicity of the triggered release groups with an extreme difference noted in the viability profiles of the T47D breast cancer cell model. Taken together, these studies indicate that this system of co-encapsulating nZnO and chemotherapeutic drugs has the potential to minimize systemic toxicity, by controlling therapeutic release, while allowing for the localized selective destruction of cancer.