Researchers have created biodegradable, magnetic nanomaterials that reduce the likelihood of lab mice having children for 30 days
Since contraceptives came into existence, women have carried the burden of using them. From hormone-changing pills to painful implanted coils, the array of options for people assigned female at birth have exacted a price from the user. Pills, which can work well for some people, can also trigger depressive mood swings and significantly harm mental health. IUDs, known as coils, have their own history of immense pain – with the issue coming to highlight how female pain is often dismissed or neglected by medical professionals.
With the rise of blood clot fears via COVID-19 injections, many compared the risks to birth control pills – explaining that people using oral contraceptives face a significantly higher blood clot risk, but there are often no other viable options.
On the other hand, male contraceptives have been incredibly limited. The options are either insecure and temporary, such as condoms, or extremely difficult to reverse, like vasectomies.
Weihua Ding, Fei Sun and colleagues wanted to create a functional male contraceptive, using one key observation – when testes are heated, sperm count lowers. Those trying for babies are often told to avoid tight pants, which overheat the genitals.
However, until now, that kind of contraception risks damaging the skin by applying heat.
How does this new male contraceptive idea work?
In one clear, fascinating phrase: Nanoparticles, heated up by magnetic fields.
Weihua Ding and Fei Sun instead looked at a type of contraceptive that would not need to be directly injected into the testes.
One type of nanoparticle was coated with polyethylene glycol (PEG) and the other with citric acid. Although the PEG-coated nanoparticles could be heated to higher temperatures, they were not as easily moved by magnets as the other ones.
So then, the researchers injected repeated doses of citric acid-coated nanoparticles into the bloodstream of mice for 2 days, guided the nanomaterials to the testes with magnets, and then applied an alternating magnetic field to the area for 15 minutes. The nanoparticles heated the testes to a temperature of 104 F, shrinking them and inhibiting the creation of sperm.
Is it long-lasting?
No.
It took 30 to 60 days after treatment for the mice to recover their sperm counts.
But it did work – the mice, despite engaging in sexual activity, could not father any pups 7 whole days after this treatment of magnetic fields and nanoparticles. This strategy needs to be adapted to humans, but signals the beginning of a whole new type of contraception.
The mice were back to fathering about 12 pups per pregnant female, at day 60.
The scientists found that nanoparticles did not damage any cells and were gradually eliminated from the body, naturally – similarly to how mRNA vaccine technology works.
The team believe that this could be the next breakthrough in the sparse landscape of male contraception.
