By Tiffany O’Callaghan | Time.com

Among the 78 research projects to receive $100,000 grants from the Bill & Melinda Gates Foundation earlier this week as part of the Grand Challenges in Global Health initiative, is an effort by researchers at the University of North Carolina, Chapel Hill, to develop a non-invasive, reversible form of birth control for men — using ultrasound. Based on preliminary trials in rats, researchers James Tsuruta and Paul Dayton hope to develop a technique that would render men temporarily infertile for up to six months after one or two ultrasound exposures.

The project is one of 10 to receive grants toward the goal of creating new technologies for contraception. Other projects geared toward men include a male contraceptive pill that researchers say would work by limiting the maturation of sperm, and research into the specific chemical compounds in the vagina that guide sperm to egg — which researchers hope to recreate in the lab and potentially use to "disrupt" sperm navigation en route to the egg. (Earlier this year, researchers at the University of California, San Francisco uncovered clues about how pH levels impact how sperm swim, and expressed hope that further research in this arena could yield possibilities for male contraception as well.)

In early trials, Tsuruta and Dayton at UNC were able to halt rats’ sperm production for up to six months after giving the animals two blasts of ultrasound spaced by two days, the New Scientist reports. The researchers believe that ultrasound disrupts sperm production with a combination of heat and shaking, and plan to further explore the mechanism at work with the new funding.

Ultimately, the researchers hope to develop a contraceptive technique that could provide long-lasting yet reversible infertility for men. As Tsuruta told the BBC:

"We think this could provide men with up to six months of reliable, low-cost, non-hormonal contraception from a single round of treatment... Our long-term goal is to use ultrasound from therapeutic instruments that are commonly found in sports medicine or physical therapy clinics as an inexpensive, long-term, reversible male contraceptive suitable for use in developing to first world countries."