Chinese scientists develop reversible, long-term male contraception technique

BEIJING, April 6 (Xinhua) -- Chinese scientists have developed a potential long-term male contraception technique that is reversible and noninvasive.

The researchers from Harbin Medical University and the National Center for Nanoscience and Technology in China described in a study recently published in the journal ACS Nano a hydrogel injected into men's spermaduct that can be cleared by extracorporeal ultrasound.

Nearly half of pregnancies worldwide are unintended mainly due to a failure of contraception, resulting in negative effects on women's health. The male contraception techniques, primarily condoms and vasectomy, cannot be both highly effective and reversible at the same time.

The hydrogel is a mixture composed of titanium dioxide, calcium chloride and sodium alginate conjugated with thioketal, according to the study.

The mixture agents are injected into the vas deferens in a one-time procedure, and they can transform from liquid to hydrogel within 160 seconds, thereby significantly blocking the tubes and inhibiting the movability of sperm, the study shows.

When fertility is needed, a noninvasive remedial ultrasound can make titanium dioxide generate reactive oxygen species, which then cleaves the thioketal to destroy the network of the hydrogel.

The refertility rate is thus restored to 100 percent, according to the study.

Ultrasounds can also monitor the occlusion and recanalization process in real time.

The technique could be used in the future as a reliable, safe and reversible male contraceptive strategy that addresses an unmet need for men to control their fertility, the researchers said.