Nanoparticles that heat testicles can help men avoid pregnancy for 7 days

This method has been applied in China to neuter cats without castration.

This method has been applied in China to sterilize cats without castration. Every man has a "refrigerator" on his body. While the body temperature in other areas of the body fluctuates at 36.5 - 37 degrees Celsius, this refrigerator should always be 1-2 degrees cooler.

Can you guess what that part is? Testicles - are hung outside the male body to separate from the influence of body temperature. The reason is because the optimal temperature for sperm production is between 34.5-36 degrees Celsius.

Warmer, sperm production will be reduced and if the testicles overheat you can even become infertile. (Advice for men is to never put a laptop on your lap, wear tight clothes when exercising, and soak for too long in a hot tub.)

But a group of Chinese scientists are looking to apply the same principle to create a male contraceptive. The method called nanocontraception - based on ferromagnetic nanorods that temporarily heat the testicles - promises to help men share the responsibility with women, because birth control pills inherently have many side effects.

While the body temperature in other areas of the male body fluctuates at 36.5 - 37 degrees Celsius, the testicles should always be 1-2 degrees cooler.

Testicle heating

Basically, the current nanocontraception prototype works like this: Doctors will place your testicles on 2 magnets. Then they injected a nearby vein with a shot containing tiny iron oxide nanorods.

These iron oxide nanorods are only 1/1000th the size of a human hair, so they can move easily in blood vessels. They will be attracted to the testicles by the magnet. The magnet is then removed and replaced with an electric coil.

Next, the doctors will send an electric current through the coil to create a magnetic field, which heats the iron oxide nanorods, thereby increasing the temperature inside your testicles to a threshold of 37-42 degrees Celsius. At this temperature, your spermatogenesis will be temporarily inhibited and disabled. Now, you can have normal sex without conceiving.

Experiments on mice show that the effect of nanocontraception therapy lasts about 1 week before the ability to bear children is gradually restored. The iron oxide nanorods are then eliminated by the liver and spleen, returning your body to its original state.

Fei Sun, a biologist who led the research project at the Micro Physics National Laboratory, said that this method has now been applied in China to neuter cats without castration.

The team says they are also aiming for applications in livestock and zoos, before perfecting it so that it can be used by men, too.

A current challenge is to make this approach simpler and more accessible. Not all men are willing to inject an injection near their testicles and place a magnet or wire under their "refrigerator" once a week.

So, Sun says, they'll need to create an oral drug containing iron oxide nanoparticles and find a way to deliver them to the testicles without the need for a magnet. The heating process can also be simplified with some kind of device, like a chair with coils inside, like wireless charging for a phone.

Most importantly, the team needed to carefully calculate the temperature and reversal of this method of contraception. Because extreme heat can atrophy the testicles and lead to a long reversal process, up to several months or even permanently irreversible.

Nanocontraception has now been successfully applied to cats. The researchers are targeting zoo animals next, before testing it on humans.

Various male contraceptive methods are being developed

We know to this day, there are more contraceptives for women, more effective and easier to use than men. They have daily pills, emergency pills, IUDs, and slow-release implants. But men who want to prevent pregnancy have only 2 options: one is a condom, the other is a vasectomy. Both methods have disadvantages.

Condoms can be torn or worn incorrectly. Some men are also allergic to latex, the material that makes standard bags. A vasectomy is an invasive surgical procedure that can be painful and difficult to reverse.

This means that once a vasectomy is done, it is very difficult to reconnect them to have children again and it is rare for a young man to choose this method of contraception. So, the search for new contraceptive methods for men continues.

Why is it so difficult to make a male birth control pill?

In 2019, a team at the Los Angeles Biomedical Institute successfully conducted a phase I clinical trial of a male contraceptive called 11-beta-MNTDC.

The drug works by blocking testosterone in the testes, reducing spermatogenesis while allowing testosterone to appear in other areas of the body, keeping men with masculine appearance, beard, hair, voice. depression and function, normal libido.

In a study in the journal Nature Communications in 2021, US scientists also found that a compound called triptonide can prevent sperm from swimming forward. Tests on monkeys taking the drug showed that they would control their fertility for 3-6 weeks.

Also last year, a team of molecular engineers at the University of North Carolina developed a vaccine that binds sperm, preventing them from swimming through vaginal mucus to reach and fertilize an egg. .

This vaccine uses anti-sperm antibodies that are able to attach to their tails and render up to 97 percent of sperm immobilized. Anti-sperm antibodies have been observed in immunosuppressed patients or in some COVID-19 patients after they have recovered from the disease.

Antibodies from the injection tightly surround the sperm, preventing them from moving freely.

In addition to chemical drugs that can cause side effects, mechanical interventions with the vas deferens in men are also being studied for improvement. In 2016, for example, about 25 men in the US had a subcutaneous vasectomy valve implanted, allowing them to turn on/off their fertility at any time.

A similar measure called vasectomy is also being developed by scientists. Instead of cutting the vas deferens in half and tying them up like current vasectomy procedures, vasectomy only involves injecting a gel that seals the lumen of the vas deferens to help prevent sperm from escaping. .

This method is much easier to reverse than a traditional vasectomy, which requires surgery to reconnect. When you no longer want to plug the vas deferens, simply inject a liquid that dissolves the gel plug and that's it.

The vasectomy method is also being developed by scientists.

A temporary vas deferens idea

However, all of these new methods of male contraception are not yet on the market or can be made available to the masses. The reason is that this research field is little interested in developing by pharmaceutical companies because the investment capital is large but the return is low.

Therefore, scientists are currently only enlisting government funding to develop these new male contraceptives. That path of research will certainly take longer than it would have been done by private companies. Therefore, it is better for men to still have condoms in their wallet in case they need them.