High-throughput Anticancer Screening of Zinc Oxide Nanoparticles Using A549 Tumor Spheroids Generated by a Droplet-based Microfluidic Device

Droplet-based microfluidics is an advanced technique to generate multicellular spheroids. Despite the advantages of this method in generating desired-sized and monodisperse cell-laden droplets, this method needs well-adopted strategies for gelling droplets and extracting them from the oil phase. Herein, we employ a droplet-based microfluidic device to generate multicellular tumor spheroids using A549 cells and alginate hydrogel. The combined in situ and ex situ gelling method employed in our microfluidic device significantly decreases spheroid damage and loss during the spheroid extraction and washing processes. The results of live/dead assays also reveal that our strategy guarantees cell viability in tumor spheroids. Moreover, the anticancer effects of zinc oxide nanoparticles are investigated using the generated tumor spheroids. The results show that the utilized agent is toxic for A549 cells, and toxicity depends on the employed doses of treatments. Although these results are similar to those of monolayer cultures reported previously, drug resistance in our tumor spheroid models is much higher.