Blocking Sperm by Reinforcing Cervical Mucus

Contraceptive Technology Innovation

Frederik Petursson Madsen

Circle Biomedical | CEO
Human sperm stained for semen quality testing in the clinical laboratory.

Human sperm stained for semen quality testing in the clinical laboratory. Photo: Bobjgalindo. Via Wikimedia Commons, licensed under CC BY-SA 4.0.

The author wishes to thank Thomas Crouzier, group leader at KTH Royal Institute of Technology in Stockholm, Sweden, for his contributions to this blog post.

Over the past several decades, contraceptive innovation has mainly focused on advancing hormone-based technologies, which proven themselves to be highly effective at preventing pregnancy. However, their side effects are often cause for discontinuance.

Concerns about hormonal contraception have been well documented by women living in the US and Europe. They are also being raised in low- and middle-income countries, where 26% of women who want to avoid pregnancy do not use hormonal contraceptives because of known or perceived side effects; another 24% opt out because they have infrequent sex and/or do not want a systemic solution.

Fueled by a new generation of women not willing to accept hormone-induced side effects, a group of mucus engineers (you heard me right) and entrepreneurs is challenging the contraceptive status quo. How did this all unfold? Back in 2014 while attending the Copenhagen Business School, I started to research the contraceptive market. I quickly realized that it is ripe for disruption because women are changing their opinions about their willingness to intake hormones. Unfortunately, the current method mix lacks a non-hormonal contraceptive that combines convenience, non-invasiveness, and high efficacy. This realization prompted me to team up with biomedical researchers in Copenhagen in search of a technology that could fill this gap. Two years later, an encounter with Thomas Crouzier, a mucus gel expert from Sweden’s KTH Royal Institute of Technology, has led to intriguing, pre-clinical research on a contraceptive technology based on cervical mucus.

Mucus gel—the lining that covers the lungs, stomach, intestines, and vagina—has many functions. It protects us from infection, provides necessary lubrication for blinking, talking, and swallowing, and hosts the billions of bacteria in our gut’s microbiome. Thomas’ team of mucus engineers is exploring how these gels can be engineered to enhance their functionalities. They discovered that it is possible to rapidly reinforce the barrier properties of mucus gels using small biopolymers. Using this approach, they demonstrated how they could slow the diffusion of dextran polymers and cholera proteins in mucus gel.

At Circle Biomedical, we are exploring how this same approach might be used for an in-depth crosslinking of ovulatory cervical mucus gel to produce a robust and effective barrier that sperm cells can’t penetrate. Imagine a woman vaginally inserting a small capsule that releases the biopolymer as it dissolves. Within one to two minutes, her cervical mucus would be fortified, making it impossible for sperm cells to permeate it.

While a final dosing level and release profile are still to be determined, we are hopeful that the impenetrable mucus state could be maintained for up to 24 hours. Aside from being convenient to use, the technology would likely generate minimal side effects since only the naturally occurring cervical mucus plug would be modified; there would be no systemic impacts. To date, our work has focused on in vitro testing of the technology, using sperm-penetration assays. We hope to conduct an in vivo proof of concept in 2019, pending funding support.

Women the world over are looking for easy-to-use, on-demand options that are non-hormonal. How novel would it be if one of their own natural barriers—cervical mucus—could be the basis for a highly effective, game-changing contraceptive?

This blog series is a collaboration with FHI 360 and can also be found on the CTI Exchange.