Sperm cell empowerment: X-ray-guided magnetic fields for enhanced actuation and localization of cytocompatible biohybrid microrobots.

Magnetic microrobots have the potential to revolutionize medicine by navigating pathways to deliver precision-targeted therapy. However, a significant challenge arises. There commonly is a trade-off between magnetic responsiveness, detectability using medical imaging systems and cytotoxicity from increased amounts of magnetic content. Addressing this, we study biohybrid microrobots comprising clusters of iron oxide nanoparticle-coated sperm cells. These sperm-templated microrobots offer benefits over microrobots driven by live sperm, such as longer shelf-life and operation time, full directional and speed control and easy fabrication. To demonstrate their potential for use in clinical settings, we developed an X-ray-guided robotic platform investigating the magnetic response and detectability of these biohybrid clusters across varying nanoparticle concentrations, notably demonstrating simultaneous actuation and localization of sperm for the first time. These improvements advance the research closer to unleashing the potential of biohybrid microrobots for medical applications within the reproductive tract.