1. Engineers at UC San Diego have developed microrobots that can navigate through the lungs to deliver cancer-fighting medication directly to metastatic tumors. 2. These microrobots, a combination of biology and nanotechnology, use green algae cells to swim and deliver drug-filled nanoparticles to lung tumors. 3. The treatment has shown improved survival rates in mice with lung metastases from melanoma, suggesting potential for future human clinical trials.