Diabetes is a rising global health problem, with incidence numbers expected to reach 643 million people by 2030¹. In the hope of providing a better quality-of-life for these patients, a less invasive treatment arises: islet transplantation. Nevertheless, there are still big challenges to overcome: graft survival (hypoxia, engraftment) plus immunosuppression aggressiveness. Thus, the main goal of this work is to synthetize hybrid nanoparticles (NPs), using a biocompatible and biodegradable polymer, poly(lactic-co-glycolic acid) - PLGA, to encapsulate immunosuppressive drugs (cyclosporine A and rapamycin) and (para)magnetic nanoparticles (MNPs), magnetite and manganese oxide, for theranostics. Inherent properties of MNPs (MRI contrast generation, O₂ production, heat generation) synergize with therapeutic effects of the drugs (immunosuppression) and their controlled delivery, to realize long sought-after goals of transplantation. The PLGA NPs were synthethized by a emulsification solvent evaporation method (double emulsion) and thoroughly characterized. The obtained particles were spherical and have a diameter of approximatedly 200 nm. Due to the presence of MnO the particles are able to generate oxygen and T₁ constrast in MRI. The particles can also generate T₂ constrast in MRI due to the presence of magnetite. The PLGA NPs presented a high encapsulation eficiency for both drugs and a controlled release over time. In conclusion, this DDS is a promising tool to overcome the main challenges of islet transplantation in type 1 Diabetes.