TechMed Twente turns sperm cells into trackable microrobots

A team of researchers from the TechMed Center at the University of Twente has transformed real sperm cells into tiny, magnetically controlled microrobots. These sperm cells can now be tracked in real time using X-ray images, a breakthrough in medical microrobotics. According to the research group, this development 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. This makes them promising candidates for use in medical microrobotics. Sperm cells are almost impossible to see in the human body using traditional imaging methods such as X-rays. They are small, have a low density, and are almost transparent to radiation. “Until now, it has been almost impossible to visualize sperm cells in the body,” says UT researcher Islam Khalil, lead author of the study.

Coating sperm cells

Together with researchers and physicians from 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-rays and responsive to external magnetic fields. For the first time, microrobots that utilize sperm cells have been tracked and controlled within a full-scale anatomical model.

Once inside, they can deliver drugs to hard-to-reach places such as the uterus or fallopian tubes. The drugs are delivered directly into the sperm cell bodies. “We are turning nature's own cell donor systems into programmable microrobots,” says Khalil. This could be an important advance for targeted treatments of conditions such as uterine cancer, endometriosis, or fibroids, for which there are currently no precise options for administering drugs.

Safely observing the moment of fertilization

In addition to the precise delivery of drugs, the technology could also offer new insights into the mystery of what exactly happens in the body during fertilization. By tracking the movement of sperm cells in the reproductive system in a non-invasive manner, researchers aim to gain a deeper understanding of unexplained infertility, the transport mechanisms of sperm cells, and potentially improve IVF techniques.

Tests showed that the sperm nanoparticle clusters remained biocompatible and did not cause significant toxicity to human uterine cells even after 72 hours of exposure. This makes them suitable candidates for future in vivo applications.