Fully automated microdfluidics device using lab-on-a-disc technology to extract and measure caffeine.Caffeine drinks are ubiquitous and it would be unimaginable for many of us to go a day without caffeine. But certainly one begins to worry about how much caffeine one consumes every day.

A team of researchers led by Prof. Young-Tae Chang from National University of Singapore and Prof. Yoon-Kyoung Cho from Ulsan National Institute of Science and Technology (UNIST), Korea, have developed convenient way to see how much caffeine is in your drink. Their invention is a fluorescent caffeine detector and a detection kit that lights up like a traffic light when caffeine is present in various drinks and solutions. The novel caffeine sensor, named Caffeine Orange, can be used for handy visualization of the amount of caffeine in coffee or energy drinks.

Naked-eye sensing for various caffeine concentrations is possible based on color changes upon irradiation with the detection kit. A light is emitted to the drink with a green laser pointer. Solutions with high caffeine concentrations turn red while solutions with moderate and low caffeine concentrations turn yellow and green, respectively, when the drink is irradiated with a laser pointer.

To fully utilize the traffic light caffeine sensor, they need to extract caffeine from solutions. An automated system incorporating microfluidics techniques, referred to as “lab-on-a-disc”, was developed by the UNIST research team, and was applied to extract and to measure caffeine.

“Applying lab-on-a-disc technology to real life application with the novel caffeine sensor is very meaningful,” said Cho. “We will continue to develop new sensors applicable to various materials utilizing lab-on-a-chip technology.”

Beverages containing caffeine, such as coffee, tea, soft drinks, and energy drinks, enjoy great popularity around the world while various studies have raised both positive and negative health related concerns. But it is clear that caffeine overdose can lead to caffeine intoxication, with symptoms such as anxiety, irregular heartbeat, and insomnia. In extreme cases, a large overdose can lead to hallucinations, depression, or even death.

“You can use this caffeine detection kit as a ‘traffic-light caffeine amount designator’,” said Chang. “The reddish orange color indicates a stop sign for people who cannot uptake caffeine, while yellow and green indicate a warning signal and safe zone respectively.”

In addition, due to its abundant existence in domestic wastage, caffeine was found to be an important indicator of natural water system pollution by domestic drain.

Caffeine Orange exhibits a 250-fold fluorescence enhancement upon caffeine activation and high selectivity responding to caffeine analogs that have similar chemical structures.

This research was supported by the Singapore-Peking-Oxford Research Enterprise and Word Class University program, and Basic Science Research Program through the National Research Foundation (NRF) by the Ministry of Education , Science and Technology in Korea.

Homepage of Yoon-Kyoung Cho

Make Caffeine Visible: A Fluorescent Caffeine “Traffic Light” Detector