Nanocontraception
Nanorods for contraception or male sterilization?
ChemPort.Ru based on RSC materials: Will nanorods be the next big male contraceptive idea?Researchers from China have developed a new method of male contraception – a rapid injection of gold nanorods into the testicles, followed by irradiation of reproductive organs with infrared light for 10 minutes.
The operation has so far been tested only on mice, but researchers are confident that it can be applied to cats, dogs and even humans.
Methods of contraception of pets have recently been in the focus of attention of veterinary researchers - in the USA alone, owners annually hand over to shelters about 4 million cats and dogs born as a result of insufficient attention to their pets. Sterilization is a common practice, however, since surgical intervention and postoperative rehabilitation of an animal takes time, researchers are trying to find simpler and cheaper alternatives that, moreover, could give only a temporary effect.
A promising direction of animal contraception is warming up the testicles of animals with, for example, hot baths or microwave radiation. Heating suppresses the functions of the testicles and can even contribute to irreversible damage to the seminal tubules, which will lead to loss of fertility. Researchers from Fei Sun's group from the University of Science and Technology of China were able to develop the idea of heating reproductive organs by developing what researchers consider a convenient, effective and cheap method of sterilization.
The process involves local anesthesia of the testicles, followed by injection of gold nanorods into them.
The nanorods are functionalized with methoxypolyethylene glycol, which leads to the fact that when the nanorods are irradiated with infrared radiation, they begin to resonate. When the testicles are irradiated with an infrared laser, the resonant vibrations of the gold nanorods contribute to the gradual heating of the testicles.
The researchers tested the new methodology on six groups of mice injected with different concentrations of gold nanorods. The smallest concentration led to the heating of the testicles to 40o !!!C, while the fertility of the mice fell to almost zero for a week, and 60 days after such treatment it grew to 50% of the initial value, followed by slow growth. A higher concentration of nanorods made it possible to heat the reproductive organs of laboratory rodents up to 45o!!!With and led to their complete loss of fertility. The behavior of the mice exposed did not change.
Sun is confident that temporary contraception, which can be achieved using small doses of gold nanorods, may be interesting not only for pet owners, but perhaps also for male contraception in humans. Sun stresses that currently the only relatively effective and appropriate method of male contraception is the use of a condom. The researcher adds that in the future he is going to test the methodology developed by the group on other animals, including great apes and, possibly – in the future – on human volunteers.
William Holt from the Zoological Society of London emphasizes that an injection will still require an appeal to a veterinarian, that is, it will not be possible to completely shift the regulation of the number of cats and dogs to their owners yet. However, Holt says that if such a technique is safe for humans, gold nanorods may well become an alternative to vasectomy.
Article by Li et al. Achieving a New Controllable Male Contraception by the Photothermal Effect of Gold Nanorods is published in the journal Nano Letters.
Portal "Eternal youth" http://vechnayamolodost.ru10.06.2013