What you probably already know: Scientists have built robots that can play soccer, mimic sloths and even do our dishes. Microrobots that can safely travel through living organisms are also paving the way for medical breakthroughs by enabling precise, minimally invasive treatments and diagnoses — including surgery — at the cellular level. Now, a team in the Netherlands is using the technology to develop magnetically controlled “sperm bots” that could lead to big breakthroughs in reproductive care.
Why? Sperm cells are nearly impossible to track inside the body using traditional imaging techniques like X-ray, partly because of their small size, density and behavior. In a 2020 study, researchers unveiled a solution: biohybrid magnetic sperm microrobots. By coating bull sperm cells in magnetic nanoparticles, the team created “biocompatible, controllable, and detectable biohybrid tools for in vivo targeted therapy.” A new study involving many of the same researchers found that by increasing the concentration of iron oxide nanoparticles (keeping the levels below the toxicity threshold for human uterine cells), the sperm bots became easier to track and control. The team then tested the bots in a 3D-printed model of the female reproductive tract that was filled with fluid, directing the tiny machines with wireless magnetic fields through a replica cervix, uterine cavity and toward the fallopian tubes. They were able to track the sperm bots in real time using X-ray imaging.
What it means: “Until now, visualizing sperm inside the body was nearly impossible,” said University of Twente researcher Islam Khalil, lead author of the study. Previous in vivo tracking methods, which have only been tested on animals, have been limited to invasive techniques involving surgery under anesthesia. For all of our modern advances in reproductive medicine, scientists still don’t fully understand many fundamental processes related to how sperm behave in the female reproductive tract. These gaps in knowledge “contribute to a high rate of unexplained infertility, lack of diagnostic tools and treatment options,” the authors write. The ability to track sperm noninvasively in real time could change this, leading to more accurate diagnoses and advancements in technologies like IVF. Sperm bots could also revolutionize the treatment of conditions such as uterine cancer, endometriosis, or fibroids by carrying medicine to hard-to-reach places, such as the uterus or fallopian tubes. “We’re turning nature’s own cell delivery systems into programmable microrobots,” Khalil said.
What happens next: While these recent studies have laid important groundwork, more research is needed before sperm bots can be deployed to help humankind. The authors note that future tests should involve more life-like soft-tissue models of female reproductive tracts, and focus on the bots’ potential to get stuck in surrounding tissues or struggle to navigate the flow of bodily fluids.
— Story by Cambrie Juarez
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