Researchers have been trying to develop a practical way to use microneedles — tiny needles less than 1 mm in length — for routine do-it-yourself medical monitoring. Microneedles are so short that they stay within the skin and do not make contact with any neurons, meaning that they cause no pain. Rather than extracting blood, they draw up fluid in the skin that contains most of the important biomarkers that blood tests look for. Several types of microneedles exist, but until now, making a practical device that quickly analyzes the fluid has proved elusive. “We have overcome this problem by developing a way to combine porous microneedles with paper-based sensors,” says Kim. “The result is low-cost, disposable, and does not require any additional instruments.”
