The production of highly sensitive sensors is a complex process: It requires many steps and the almost dust-free environment of special cleanrooms. A research team from Materials Science at Kiel University (CAU) and from Biomedical Engineering at the Technical University of Moldova has now developed a procedure to produce extremely sensitive and energy-efficient sensors using 3-D printing. The simple and cost-effective production method is also suitable for industrial production, the team recently explained in the renowned specialist journal Nano Energy. Their sensor, which they present here, is able to precisely measure the concentration of acetone vapor using a special structuring at the nano level. As the acetone concentration in the breath correlates with blood sugar levels, the research team hopes to have made a step towards producing a breath test for diabetics that could replace the daily checking of their blood sugar levels by finger pricks.