Oxidative stress has been described in diseases such as Amyotrophic Lateral Sclerosis, presenting a potential target for the development of new therapies. Magnetic Resonance Imaging (MRI) is a technique frequently used to study the nervous system. Manganese ions (Mn2+) are part of a healthy brain and can be used for long-term T1-weight imaging due to its ability to be a contrast agent. Thus, Manganese Enhanced MRI has been used to guide intrathecal drug/cell delivery. Additionally, the ability to scavenge Reactive Oxygen Species (ROS) has been studied, using manganese dioxide (MnO2) nanoparticles, which decompose hydrogen peroxide in water, oxygen and Mn2+. In this work, we propose the development of nanoreactores composed of a methacrylated gellan-gum (GG-MA) blended with manganese dioxide (MnO2) nanoparticles, which will be delivered and guided by MRI. Due to its biocompatibility, biodegradability, easy functionalization and high affinity to Mn2+, GG-MA matrix was used to reduce the toxicity of the MnO2 nanoparticles. A previously described protocol was followed to produce GG-MA, and further characterization was performed by FTIR and 1H-NMR. Regarding the MnO2 nanoparticles, a comparison between synthetized and commercially available ones was performed. The nanoreactors were submitted to several tests regarding their rheology, stability, permeability and morphology. Cell viability and ROS scavenging ability of these nanoreactors will also be studied.