Polymeric layer-by-layer microcapsules containing iron oxide magnetic nanoparticles exposed to breast cancer cells: A viability study using tetrazolium-based (MTT) and calcein-AM assays (LIVE-DEAD)

Layer-by-Layer capsules combined with nanoparticles are emerging as promising and secure vehicles for drug delivery. The integration of nanoparticles introduces intelligent functionalities, particularly in targeted therapy. This investigation focused on assessing the impact of drug carriers on the viability of MDA-MB-231 breast cancer cells. Specifically, polymeric capsules were synthesized using a Layer-by-Layer approach, incorporating iron oxide magnetic nanoparticles. The Layer-by-Layer method involved constructing six bilayers of PAH/PSS on a CaCO₃ template, with iron oxide magnetic nanoparticles (MNPs) interspersed between the layers. The core was removed by applying the chelating agenlt EDTA, resulting in the fabrication of hollow capsules. Characterization of the capsules was performed using SEM and bright-field microscopy. Successful synthesis was confirmed as capsules/MNPs responded to an external magnetic field. Various concentrations of capsules/MNPs were introduced to cells, and cell viability was assessed using the tetrazolium-based MTT assay for quantitative measurements and the calcein-AM assay (Live-dead) for real-time visualization of live and dead cells. The findings revealed that adding 20 µl of capsule suspension (containing 14,000 capsules) to 100 µl of cell culture suspension preserved 90% cell viability. This study implies a feasible concentration of capsules for delivering compounds to cancer cells without inducing toxicity to normal cells.