{"id":52126,"date":"2025-10-07T15:43:33","date_gmt":"2025-10-07T19:43:33","guid":{"rendered":"https:\/\/engineering.jhu.edu\/materials\/?post_type=news&p=52126"},"modified":"2025-10-16T10:16:37","modified_gmt":"2025-10-16T14:16:37","slug":"new-sensor-detects-markers-evident-in-human-breath-toxins-in-air","status":"publish","type":"news","link":"https:\/\/engineering.jhu.edu\/materials\/news\/new-sensor-detects-markers-evident-in-human-breath-toxins-in-air\/","title":{"rendered":"New Sensor Detects Markers Evident in Human Breath, Toxins in Air"},"content":{"rendered":"

A team led by Johns Hopkins materials scientists has developed a new type of potentially wearable sensor using specially designed plastic-like materials that can detect acetone in human breath\u2014a marker that could help diagnose diabetes\u2014and identify other harmful chemicals in the air for environmental monitoring. Their research appears in the Journal of Materials Chemistry C<\/em><\/a>.<\/em><\/p>\n

\u201cThis technology could change the game in how we monitor our health and the environment,\u201d said lead author Howard Katz<\/a>, a professor of materials science and engineering at the Whiting School of Engineering. \u201cImagine having a small wearable device that could sniff out diabetes through your breath or alert you to dangerous air pollution in real time.\u201d<\/p>\n

Katz\u2019s team set out to modify existing organic field-effect transistors or OFETs\u2014electronic switches made from carbon-based materials that can change their electrical properties when exposed to chemicals\u2014to elicit heightened electrical responses to volatile organic compounds in the air. VOCs are chemicals, such as formaldehyde, benzene, and acetone, that rapidly evaporate and become airborne, causing potential health issues.<\/p>\n

\u201cWe wanted to create a semiconductor, which is a tiny switch that controls the flow of electricity in these devices, using a polymer we had experimented with before. We adjusted the polymer\u2019s molecular composition by adding aniline, a substance commonly used in dyes, because we thought that it would detect gaseous acetone,\u201d he said.<\/p>\n

The researchers already knew that diketopyrrolopyrrole (DPP) polymers were good conductors of electricity and that aniline is reactive with acetone. They combined the two to attempt to make the device especially sensitive to acetone, making three polymers with varied concentrations of aniline.<\/p>\n

\u201cWe chose to use different amounts of aniline to assess which would enable the device to work best,\u201d says Katz. \u201cWe knew aniline could decrease the amount of current that could flow in a material, so the device would need more voltage to get more current. Too much voltage would make the semiconductor unstable and cause the OFET not to work.\u201d<\/p>\n

After aniline was attached to the polymers and placed in the device as semiconductors, the researchers conducted separate experiments with the three compounds by placing them in an airtight chamber. They then measured the current running through the device when the chamber contained only air before adding a very small amount of acetone, about 50 parts per million. \u201cWhen the device was in the controlled environment with only air, the current running through it steadily increased. As soon as we added acetone, the current decreased \u2013 indicating that the transistors had recognized the presence of the gas and responded to it,\u201d says Katz.<\/p>\n

The team then inserted acetic acid, commonly known as vinegar, into the chamber, followed by dimethyl carbonate, a substance used in lithium-ion batteries. \u201cThese substances are molecularly similar to acetone, so we wanted to ensure that the device we made was especially sensitive to acetone and not just any gas,\u201d says Katz.<\/p>\n

After they found that the current continued to increase when the other gases were introduced, they tested the compounds as liquids in the chamber to see if the device\u2019s response changed. \u201cIn this instance, we saw that the device was far more responsive to liquid acetone, an interesting finding which we hope to investigate further,\u201d says Katz.<\/p>\n

With their preliminary results, the researchers created more of the aniline-DPP polymer devices, adjusting the amount of aniline attached to the polymer, and repeated the experiments.<\/p>\n

\u201cWe wanted to make the best combination to allow the most possible current to run through the device while maintaining its super-selectivity to detect gaseous acetone,\u201d says Katz. \u201cWe made about half a dozen of these devices total, discarding one polymer from the first round of experiments because the combination of polymer and acetone prevented current from entering the device. We learned that we can\u2019t add too much aniline because the device won\u2019t work.\u201d<\/p>\n

Having fine-tuned their device to achieve maximum sensitivity to acetone, the team is now working to bring their technology to market.<\/p>\n

\u201cWe are moving forward with scaling this material up and producing it, perhaps as a wearable device that could detect illness within the body,\u201d says Katz.<\/p>\n

The research team included Sasikumar Mayarambakam, a postdoc in materials science and engineering at the Whiting School; Riley Bond, ENGR\u201925 (PhD), Jimetochukwu Solomon, a researcher at Coppin State University’s Center for Organic Synthesis, and Hany F. Sobhi, professor of organic and clinical chemistry at Coppin State University.<\/p>\n

This work was funded by the National Science Foundation, Partnerships for Innovation.<\/a><\/p>\n","protected":false},"template":"","class_list":["post-52126","news","type-news","status-publish","hentry","news_categories-research"],"acf":[],"yoast_head":"\nNew Sensor Detects Markers Evident in Human Breath, Toxins in Air - Department of Materials Science & Engineering<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/engineering.jhu.edu\/materials\/news\/new-sensor-detects-markers-evident-in-human-breath-toxins-in-air\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"New Sensor Detects Markers Evident in Human Breath, Toxins in Air - Department of Materials Science & Engineering\" \/>\n<meta property=\"og:description\" content=\"A team led by Johns Hopkins materials scientists has developed a new type of potentially wearable sensor using specially designed plastic-like materials that can detect acetone in human breath\u2014a marker…\" \/>\n<meta property=\"og:url\" content=\"https:\/\/engineering.jhu.edu\/materials\/news\/new-sensor-detects-markers-evident-in-human-breath-toxins-in-air\/\" \/>\n<meta property=\"og:site_name\" content=\"Department of Materials Science & Engineering\" \/>\n<meta property=\"article:modified_time\" content=\"2025-10-16T14:16:37+00:00\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data1\" content=\"4 minutes\" \/>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"New Sensor Detects Markers Evident in Human Breath, Toxins in Air - 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