The gel, which consists of the polymers PBA (phenylboronic acid) and SHA (salicylhydroxamic acid), stays liquid while in contact with the acidity that is normal in a vagina. However, when the pH level gets lower, which happens when semen is introduced, the gel molecules bind together and become semi-solid.

The team found it efficiently traps HIV viruses and will further study its ability to block other pathogen viruses and spermatozoids. A paper on their research was published in the journal Advanced Functional Materials.

"We did it to develop technologies that can enable women to protect themselves against HIV without approval of their partner," said Patrick Kiser, Utah bioengineering professor, who is on the research team behind the gel.

The “molecular condom” is a step forward in microbicide research. Previously scientists focused on solutions that killed viruses or prevented their replication rather than blocked them physically as happens with the polymer gel.

Kiser says he hopes to see the gel pass clinical trials in three to six years. The resulting product is estimated to have a shelf cost per dose comparable to that of male condoms.

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