Systems, methods, and devices for treating cancer can produce field potentials of between 20 mV and 70 mV. In some cases, systems, methods, and devices provided herein can include a plurality of particles. The particles can include at least a first material and at least a second material, which can have electrode potentials configured to form a galvanic couple in the location of cancerous tissue to form a field potential adapted to preferentially target cancerous tissue over healthy tissue.
