Electrical Engineering students Claire Lochner, Yasser Kahn and Adrien Pierre created an organic medical sensor that measures oxygen in the blood. Thanks to a recent invention by Berkeley engineers, measuring oxygen levels in the blood could soon be as simple as strapping a bandage on a finger. Although pulse oximeter sensors — which measure blood-oxygen saturation levels and pulse rate — are already available, they tend to be inconvenient and somewhat expensive. As an alternative to the conventional device, Electrical Engineering doctoral students Yasser Kahn, Claire Lochner and Adrien Pierre developed an organic version of the pulse oximeter sensor that is pliable and cheap enough for everyday use. Typically, the devices use rigid materials that constrict movement, but the students used flexible organic electronics that read pulse and oxygen as accurately as the earlier type. Because it is vital to maintain a certain level of oxygen in the blood stream, pulse oximeters also use two different colors of light to determine the ratio between oxygen-rich and oxygen-poor blood. Instead of using the typical green and red infrared LEDs in the sensor to measure oxygen levels, the students used organic green and red light, which proved to be more flexible and just as reliable. “With further improvement, this sensor can be placed on different parts of the body — even placed in the body — to see if a newly transplanted organ, for example, is getting enough oxygen,” Khan says. The results from the project were recently published in the science journal Nature Communications. Their work is the first step in “creating medical sensors that are more like smart Band-Aids — flexible, comfortable, inexpensive and disposable,” Lochner adds. Khan, who focuses on wearable medical electronics, says that his passion for working on projects that have a “real-life impact” aligns with the team’s future goals for the sensor. Although it will still be a few more years until the invention is available to the public, the students hope to begin clinical testing as soon as they have honed the prototype.