Flexible electronic sensors based on paper — an inexpensive material — have the potential to some day cut the price of a wide range of medical tools, from helpful robots to diagnostic tests. Scientists have now developed a fast, low-cost way of making these sensors by directly printing conductive ink on paper. They published their advance in the journal ACS Applied Materials & Interfaces.
Anming Hu and colleagues point out that because paper is available worldwide at low cost, it makes an excellent surface for lightweight, foldable electronics that could be made and used nearly anywhere. Scientists have already fabricated paper-based point-of-care diagnostic tests and portable DNA detectors. But these require complicated and expensive manufacturing techniques. Silver nanowire ink, which is highly conductive and stable, offers a more practical solution. Hu’s team wanted to develop a way to print it directly on paper to make a sensor that could respond to touch or specific molecules, such as glucose.
The researchers developed a system for printing a pattern of silver ink on paper within a few minutes and then hardening it with the light of a camera flash. The resulting device responded to touch even when curved, folded and unfolded 15 times, and rolled and unrolled 5,000 times. The team concluded their durable, lightweight sensor could serve as the basis for many useful applications.