birth control

Nano-fabric defends against HIV and sperm

U. WASHINGTON (US) — Scientists have developed an electrically spun cloth with nanometer-sized fibers that can simultaneously prevent HIV and offer contraception.

As reported in PLOS ONE, the cloth can dissolve to release drugs, providing a platform for cheap, discrete, and reversible protection.

“Our dream is to create a product women can use to protect themselves from HIV infection and unintended pregnancy,” says corresponding author Kim Woodrow, assistant professor of bioengineering. “We have the drugs to do that. It’s really about delivering them in a way that makes them more potent, and allows a woman to want to use it.”

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Electrospinning uses an electric field to catapult a charged fluid jet through air to create very fine, nanometer-scale fibers. The fibers can be manipulated to control the material’s solubility, strength, and even geometry. Because of this versatility, fibers may be better at delivering medicine than existing technologies such as gels, tablets, or pills.

No high temperatures are involved, so the method is suitable for heat-sensitive molecules. The fabric can also incorporate large molecules, such as proteins and antibodies, which are hard to deliver through other methods.

At a lab meeting last year, Woodrow presented the concept, and co-authors Emily Krogstad and Cameron Ball, both first-year graduate students, pursued the idea.

How it works

They first dissolved polymers approved by the Food and Drug Administration and antiretroviral drugs used to treat HIV to create a gooey solution that passes through a syringe.

As the stream encounters the electric field it stretches to create thin fibers measuring 100 to several thousand nanometers that whip through the air and eventually stick to a collecting plate (one nanometer is about one 25-millionth of an inch). The final material is a stretchy fabric that can physically block sperm or release chemical contraceptives and antivirals.

“This method allows controlled release of multiple compounds,” Ball says. “We were able to tune the fibers to have different release properties.”

One of the fabrics they made dissolves within minutes, potentially offering users immediate, discrete protection against unwanted pregnancy and sexually transmitted diseases.

Another dissolves gradually over a few days, providing an option for sustained delivery, more like the birth-control pill, to provide contraception and guard against HIV.

The fabric could incorporate many fibers to guard against many different sexually transmitted infections, or include more than one anti-HIV drug to protect against drug-resistant strains (and discourage drug-resistant strains from emerging). Mixed fibers could be designed to release drugs at different times to increase their potency, like the prime-boost method used in vaccines.

The electrospun cloth could be inserted directly in the body or be used as a coating on vaginal rings or other products.

Electrospinning has existed for decades, but it’s only recently been automated to make it practical for applications such as filtration and tissue engineering. This is the first study to use nanofibers for vaginal drug delivery.

‘Multiple options’

While this technology is more discrete than a condom, and potentially more versatile than pills or plastic or rubber devices, researchers say there is no single right answer.

“At the time of sex, are people going to actually use it? That’s where having multiple options really comes into play,” Krogstad says. “Depending on cultural background and personal preferences, certain populations may differ in terms of what form of technology makes the most sense for them.”

The team is focusing on places like Africa where HIV is most common, but the technology could be used in the US or other countries to offer birth control while also preventing one or more sexually transmitted diseases.

The research to date was funded by the National Institutes of Health and the University of Washington’s Center for AIDS Research.

The team will use a recently awarded Gates Foundation grant to evaluate the versatility and feasibility of their system. The group will hire more research staff and buy an electrospinning machine to make butcher-paper sized sheets. The expanded team will spend a year testing combinations that deliver two antiretroviral drugs used to treat HIV and a hormonal contraceptive, and then six months scaling up production of the most promising materials.

Source: University of Washington

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