Fluorescent lab-on-a-chip device detects caffeine

For most people, it would be crazy to imagine going one day without consuming a caffeinated drink such as coffee, tea, cola, or an energy drink to stay alert. What's more, most are likely unaware of how much caffeine they're actually consuming—too much of it can have dangerous effects on health. Recognizing this, researchers at the National University of Singapore and Ulsan National Institute of Science and Technology (UNIST; Ulsan, Korea) have developed a fluorescent caffeine sensor and detection kit that warns the consumer when caffeine is present in their drinks—and tells them if they need to curb their intake.

Dubbed Caffeine Orange, the non-toxic, fluorescent caffeine sensor is a microfluidic lab-on-a-disc device that measures caffeine concentrations in beverages in about 1 min. When a sample in the sensor is irradiated with a 532 nm green laser pointer, it then signals the consumer like a traffic light: Beverages containing high caffeine concentrations turn red, while those with moderate and low caffeine concentrations turn yellow and green, respectively. The sensor exhibits 250-fold fluorescence enhancement upon caffeine activation, giving consumers a clear signal.

The Caffeine Orange kit is currently in prototype stage, but if commercialized would cost about $2 to produce, says Prof. Young-Tae Chang of the National University of Singapore, who led the work in tandem with Prof. Yoon-Kyoung Cho of UNIST.

Full details of the work appear in the journal Scientific Reports; for more information, visit www.nature.com/srep/2013/130723/srep02255/full/srep02255.html.