Biosensors in Smart Fabrics Monitor Respiration Rate and Temperature

This will provide point-of-care diagnostics to health-care professionals and greater freedom for patients.

Pentacene, a hydrocarbon molecule, and carbon nanotubes were used to develop the sensors. The addition of carbon nanotubes to the pentacene increased sensor sensitivity. As an organic semiconductor, pentacene is efficient and easy to control. Both sensors were fabricated directly on flexible polymeric substrates.

The strain sensor, for monitoring respiration rate, consists of a Wheatstone bridge, an instrument that measures unknown electrical resistance, and a thin pentacene film that acts as a sensing layer. A physiologic strain, such as breathing, creates a mechanical deformation of the sensor, which then affects the electrical current's resistance. The temperature sensor uses a thin-film transistor, which deposits thin film semiconductors on substrates. The thin-film transistor enables observation of electrical current in linear response to temperature change.

Electrical-engineering scientists at the University of Arkansas (Fayetteville, AR, USA) fabricated and tested these two similar but slightly different biosensors. "We're trying to move diagnostic testing out of the laboratory and directly to the patient,” said Dr. Taeksoo Ji, assistant professor of electrical engineering. "Although there has been some success at this effort over the past decade, traditional materials are not suitable for manufacturing low-cost, large-area sensor devices. The advantages of organic semiconductors will allow manufacturers to produce devices that are light, flexible, and easily integrated into biomedical applications such as smart vests and fabrics.”

Prof. Vijay Varadan, director of the college of Engineering's Center for nano-, bio-, and info-technology sensors, and professor of neurosurgery at the University of Arkansas, reported that the "smart” fabric could monitor vital signs and collect and send data to an information hub in real time. The gathered information provides immediate detection of physiologic abnormalities, which will allow physicians to begin treatment or prevent illness before problems reach an acute stage.


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