Fluorescent nanogels as methotrexate transporters and their potential application in breast cancer therapy

Nanometric drug delivery systems (DDSs) like nanogels are the future materials in nanomedicine against cancer. Fluorescent DDS have the potential to generate an application in theragnostics. In this study, intrinsic fluorescent nanogels (FNG) were synthesized <i>via</i> a scalable polymerization methodology based on surfactant-free emulsion polymerization of <i>N,N′</i>-diethyl(aminoethyl methacrylate) (DEAEM) and poly(ethylene glycol) methacrylate (PEGMA) using a fluorescent crosslinker. They were characterized by NMR, dynamic light scattering (DLS), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), TGA, and fluorescence spectroscopy. These nanogels are responsive; the hydrodynamic diameter and fluorescence intensity depend on the pH; the higher the pH, the smaller the size and the higher the fluorescence intensity. Methotrexate (MTX) was loaded into the nanogels for its physicochemical characterization and <i>in vitro</i> evaluation of cell viability against the breast cancer cell lines MDA-MB-231 and MCF-7. Cytotoxicity depended on the composition of the fluorescent nanogel; MTX showed resistance in the cell lines evaluated; however, once loaded into the nanogel, it was possible to develop a promising system for the delivery of MTX to potentially treat breast cancer, including triple-negative breast cancer cells.