Researchers have magnetized cattle sperm using tiny beads, enabling them to be guided by external fields toward an egg. The method formed healthy embryos in lab tests at rates matching standard sperm. It aims to support future in vivo fertilization inside the body.
Mariana Medina-Sánchez at CIC nanoGUNE in Spain led the work. Her team incubated cattle sperm with iron oxide and polystyrene beads, attaching about 30 per sperm head. The beads allowed directional control via weak magnetic fields without harming swimming speed or viability.
Embryos developed normally after the beads detached during egg penetration. The approach seeks to reduce invasive IVF steps by directing sperm through the reproductive tract to the fallopian tubes.
Kylie Dunning of Adelaide University called the study an exciting proof of concept. She noted that further tests are needed to confirm fertilization and healthy offspring in living animals.
The magnetic beads are visible on ultrasound and could be cleared naturally or removed by catheter. Results appear in a bioRxiv preprint posted in April.
