We have seen a bunch of interesting biohybrid robot concepts here in the past. Researchers at Case Western Reserve University have managed to combine tissues from a sea slug with flexible 3D printed components to build biohybrid robots that crawl like sea turtles on the beach.
The muscle is currently controlled by an external electrical field, but the next iteration will include ganglia. Such robots can be used to locate the source of a toxic leak in a pond or search the ocean floor for things. More info is available here.