Electrohydrodynamically Atomized pH-Responsive PLGA/ZnO Quantum Dots for Local Delivery in Lung Cancer

Targeted drug delivery to cancerous tissues using nanomaterials is a challenging task that is fast gaining attention. Here, we report the fabrication of ZnO quantum dots (QDs) encapsulated in the biodegradable copolymer poly(DL-lactide-co-glycolide) (PLGA) nanoparticles using an electrohydrodynamic atomization process to enhance cytotoxicity against the metastatic cancer A549 cell line. The encapsulation and the small size increased the cellular uptake of the PLGA/ZnO QDs. Furthermore, the PLGA/ZnO QDs are pH-responsive and can therefore target cancerous cells based on the acidic tumor microenvironment, leaving healthy cells less affected. PLGA/ZnO QDs induced cell death and obstructed cell invasion and migration at low concentrations (7.5 µg/mL). We verified these activities through thiazolyl blue, tetrazolium blue (MTT), scratch assay, and clonogenic assays on metastatic A549 cells, with normal human lung cells, Human Small Airway Epithelia Cells (SAECs) as the controls. Thus, PLGA-encapsulated ZnO QDs, owing to their selective localization, ability to enter cells, cytotoxicity, and retention effect, could provide a potential platform for tumor-directed drug therapy.