www.who.int/news-room/fact-sheets/detail/endometriosis">200 million people, including children, around the world have endometriosis, a chronic disease in which the lining of the uterus grows outside of the uterus. More severe symptoms, such as extreme pain and potentially infertility, can often be mitigated with early identification and treatment, but no single point-of-care diagnostic test for the disease exists despite the ease of access to the tissue directly implicated. While Penn State Professor Dipanjan Pan said that the blood and tissue shed from the uterus each month is often overlooked - and even stigmatized by some - as medical waste, menstrual effluent could enable earlier, more accessible detection of biological markers to help diagnose this disease.
Pan and his group developed a proof-of-concept device capable of detecting HMGB1, a protein implicated in endometriosis development and progression, in menstrual blood with 500% more sensitivity than existing laboratory approaches. The device, which looks and operates much like a pregnancy test in how it detects the protein, hinges on a novel technique to synthesize nanosheets made of the atomically thin 2D material borophene, according to Pan, Dorothy Foehr Huck & J. Lloyd Huck Chair Professor in Nanomedicine and corresponding author of the study detailing the team's work, published this week (July 17) on the cover of ACS Central Science.
"Despite the significant potential of menstrual effluent as a diagnostic tool for women's health, it often faces substantial challenges due to social stigma and limited access to affordable diagnostic methods," said Pan, who is a professor of nuclear engineering and of materials science and engineering. He is also affiliated with the Departments of Biomedical Engineering and of Radiation Oncology.
Existing diagnostic approaches involve intravenous blood tests and laboratory analyses coupled with imaging studies and extensive patient history collection for clinicians to make a definitive diagnosis. Such challenges contribute to delays in diagnosing endometriosis, with one study of 218 women revealing a delay of up to 12 years in the United States, he explained.
"By leveraging the novel 2D material borophene, our approach offers a unique opportunity to reduce menstrual stigma while advancing women's health," Pan said.
Borophene is a derivative of the chemical element boron similar to the more commonly researched graphene, a lightweight 2D material made from carbon, Pan said. Borophene, however, boasts an advantage over graphene.
"Work from my group demonstrates that borophene is highly biocompatible and a biodegradable material, making it highly suitable for biomedical applications," Pan said, but he noted that fabricating the pure form of the material can pose challenges. Traditional methods involve several steps, which can degrade the quality and yield of the desired resulting product, and harsh solvents, like isopropyl alcohol, that can make the product unsuitable for biomedical applications.
In this study, the researchers swapped out the alcohol solvent for water. They dispersed powdered boron in the water, breaking down the chemical and reforming it into "pristine" nanosheets, according to Pan. The team then fixed antibodies that would recognize the protein HMGB1 to the nanosheets.
"Think of planting a garden," Pan said. "The ground - the nanosheets - must be even and clear of weeds before you can fertilize the soil - adding the antibodies. Then, you have the best environment to support the desired vegetables - the HMGB1 proteins. That was our goal here, to create a uniform foundation on which the antibodies could recognize and capture the HMGB1 proteins."
Pan and his team used multiple imaging and chemical analysis techniques to validate that the antibodies correctly caught and bound to HMGB1, the protein implicated in endometriosis.
The researchers arranged the validated nanosheets into a test device, similar to a pregnancy test that displays either one line if negative or two if positive. As the blood sample flows over the test strip, if any HMGB1 proteins are present, they bind to the antibodies, which darkens the test strip.
To test the sensitivity of the device, the researchers spiked menstrual blood with various concentrations of HMGB1 and found the test successfully detected the protein at low concentrations with five times more sensitivity compared to existing laboratory tests that require extensive preparation and analysis.
"Clinical evidence indicates that HMGB1 levels in menstrual blood are significantly elevated in individuals with endometriosis compared to healthy controls," Pan said. "However, early-stage or asymptomatic cases may present with only modest increases - that's why high sensitivity to low HMGB1 concentrations is essential. Early detection is critical for timely intervention. Unlike other laboratory-based tests, our approach balances sensitivity with practicality for settings without centralized medical access and laboratory facilities, addressing unmet needs in endometriosis screening."
Pan said the test could even be integrated into menstrual pads, enabling discreet and convenient monitoring of HMGB1 levels at home.
"The ability to detect critically important biomarkers via a decentralized platform, like our approach, empowers patients with facilitating widespread use in more rural areas or settings without expansive medical resources," Pan said. "This study highlights the broader research opportunities essential for realizing next-generation biotechnologies, with 2D materials at their core, and I'm excited about the potential of this highly promising class of nanomaterial for advanced health care applications."
Next, the researchers said they plan to scale up their approach for clinical studies, improve the device's sensitivity even further, and expand the test to detect additional disease biomarkers such as HPV and cervical cancer.
Other contributors, all who work in or completed work as students in Pan's laboratory at Penn State, include co-first authors Satheesh Natarajan, postdoctoral researcher in nuclear engineering, and Ketan Dighe, graduate student in biomedical engineering; Teresa Aditya, assistant research professor of nuclear engineering; Pranay Saha, postdoctoral researcher in nuclear engineering; David Skrodzki, graduate student in materials science and engineering; Purva Gupta, who graduated from Penn State with a bachelor of science in biomedical engineering in May and who helped support the effort to establish free menstrual product dispensers across University Park in 2023; Nivetha Gunaseelan, doctoral student in biomedical engineering; Shraddha Krishnakumar, doctoral student in biomedical engineering. Dighe, Gupta and Gunaseelan were awarded the inaugural National Academy of Inventors Dr. Barry B. Bercu Biomedical Collegiate Inventor Prize in 2024 for their work on this project.
The Centers for Disease Control and Prevention, the U.S. National Science Foundation, the Department of Defense Congressionally Directed Medical Research Program and the National Institutes of Health supported this work.
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