Research is early, but Chinese scientists say they use bartender tricks to trigger a new, reversible male contraceptive.
In rats, the method successfully maintained sexually active men impregnating women for more than two months.
"The two most commonly used male contraceptives are condom and vasectomy," said the team led by Xiaolei Wang of Nanchang University. "Reliable and reversible medium-term [2 to 20 weeks] the contraceptive method between a one-time condom and permanent contraception is urgently needed. "
Their potential solution was inspired by colored layered cocktails, often made by bartenders. In these liquid mixtures, different layers are formed in the glass. However, when mixing or heating, the layers are combined into a uniform liquid.
A promising but long way
So the Wang group has developed a form of male contraception in which material layers are injected into the vas deferens – the pipeline that semen travels from the testis to the urethra – to block it.
The blocking continues as long as the heat is not sufficient for the blocked area, causing the layers to mix, break, and disconnect the drainage pipe.
The Chinese group claims to have tested this method in male rats by injecting four layers of material into the container. Gradually, the injected layers were hydrogel, which forms a physical barrier to sperm; gold nanoparticles that heat when irradiating near infrared radiation; ethylenediaminetetraacetic acid (EDTA), a chemical that decomposes hydrogel and also kills sperm; and another layer of gold nanoparticles.
While in place, the liquid layers in vas deferens prevented male rats from impregnating females for more than 2 months, Wang's team reported on January 30 in the journal ACS Nano.
But when some male rats used to hold an infrared lamp several times, the layer was mixed and dissolved, and the male rats were able to impregnate women again. It offers an "effective and reversible way to fill the gaps in the current medium-term contraceptive strategy" for men, the team said.
But "although our method is promising, there is still a long way to practice," the Chinese team said. "Further animal experiments are needed to test material safety," they said, and the result is that animals often fail to climb people.
One fertility specialist in the United States has agreed that much more studies are needed.
"This study is a very preliminary look at male contraceptive injection," Dr. Mary Rausch of Northwell Health Fertility, Manhattan, New York. "Although it's a long way to go before it's ready for a test or certainly for people, it will be a breakthrough in medicine if it becomes fruitful.