RESUMO
In this study, we performed a systematic evaluation of the synthesis parameters of a multiresponsive core-shell nanoplatform (Fe3O4 nanoparticles coated by poly(N-isopropylacrylamide). These nanocomposites allow the possibility of controlling specific properties, such as particle size and morphology. The polymer coating was performed by in-situ free-radical polymerization of N-isopropylacrylamide on Fe3O4 nanoparticles to obtain a nanocomposite with a core-shell structure. We monitored the size and morphology of the nanocomposite by scanning transmission electron microscopy. Electrophoretic mobility determined the evolution of ζ-potentials during coating. We assessed the functionalization of the Fe3O4 nanoparticles by Fourier-transform infrared spectroscopy and ultraviolet-visible spectroscopy. The core-shell systems exhibited a collapsed structure when heated above the lower critical solution temperature, which was determined by dynamic light scattering. Squid based vibrating sample magnetometer tests were performed to verify superparamagnetic behavior at room temperature. The platform was approved as biocompatible for the HeLa and MDA-MB-231 cell lines by MTT assays, and it shows the desired properties for potential use in localized and controlled drug delivery.