Cells coated with magnetic nanoparticles could transform future of fertility

A team of researchers at the TechMed Center of the University of Twente has transformed real sperm cells into tiny, magnetically controlled microrobots. These sperm bots can now be tracked in real time using X-ray imaging, a breakthrough in medical microrobotics.

This development, now published in npj Robotics, could open new doors in reproductive medicine, drug delivery, and infertility diagnostics.

Sperm cells are naturally fast, flexible swimmers that can navigate the complex environment of the female reproductive tract, making them promising candidates for use in medical microrobotics. Sperm cells are nearly impossible to see inside the human body using traditional imaging methods like X-ray. They’re small, low-density, and nearly transparent to radiation.

“Until now, visualizing sperm inside the body was nearly impossible,” says UT researcher Islam Khalil, lead author of the study.

Coating sperm cells

Together with researchers and medical professionals from the Radboud University Medical Center and the University of Waterloo (Canada), researchers at the University of Twente coated real sperm cells with magnetic nanoparticles. This made them visible under X-ray and responsive to external magnetic fields. For the first time, these sperm-based microrobots can now be tracked and steered inside a life-sized anatomical model.

Once inside, they can potentially deliver drugs to hard-to-reach places such as the uterus or fallopian tubes. The medication is loaded directly into the sperm cell bodies. “We’re turning nature’s own cell delivery systems into programmable microrobots,” says Khalil. This could be an important advancement for targeted treatments for conditions like uterine cancer, endometriosis, or fibroids, all of which currently lack precise drug delivery options.

Peeking safely into fertilization

In addition to precise drug delivery, the technology could also offer new insights into the mystery of what happens inside the body during fertilization. By tracking sperm movement noninvasively inside the reproductive system, researchers hope to better understand unexplained infertility, sperm transport mechanisms, and even improve IVF techniques.

Tests showed that the sperm-nanoparticle clusters remained biocompatible, causing no significant toxicity to human uterine cells even after 72 hours of exposure. This makes them suitable candidates for future in-vivo applications.