In this age of laser-etched microfluidic lab-on-a-chip devices that analyze samples of bodily fluids on the spot, it's kind of ... fun, perhaps, to hear about a similar device that could conceivably be assembled by a grade school student, using their allowance money. The matchbox-sized sensor, developed by scientists from The University of Texas at Austin, is designed to detect acute pancreatitis using blood samples. Important as its purpose may be, though, the materials used to build the device include things like household aluminum foil, milk, a 12-cent LED bulb, and JELL-O.

Acute pancreatitis involves a sudden inflammation of the pancreas, and can cause severe stomach pain, nausea, fever, shock and even death. The sensor for detecting the disorder was created by U Texas professor of chemistry and biochemistry Richard Crooks, and his graduate student Brian Zaccheo.

The testing process begins with a drop of blood being placed onto a layer of gelatin and milk protein. If that blood contains high levels of the enzyme trypsin, which is over-abundant in people with acute pancreatitis, it will break down the gelatin. Next, a drop of sodium hydroxide – also known as lye – is added to the mix. If the gelatin was already broken down by trypsin, then the lye will have no trouble trickling down to a strip of the aluminum foil. Once that foil has corroded, a circuit will be able to form within the sensor, between a magnesium anode and an iron salt at the cathode. Within no more than an hour, the LED will proceed to illuminate, letting everyone know that medical attention is needed.

The sensor doesn't require batteries or any outside power source, and each one would likely cost less than one U.S. dollar to produce.

Zaccheo and Crooks believe that the device would be ideal for use not only in developing nations, but also in situations where batteries aren't readily available. Because of the speed at which it produces results, it could even be useful in well-equipped hospitals.

"I want to develop biosensors that are easy to use but give a high level of sensitivity," said Zaccheo. "All you need for this, for instance, is to know how to use a dropper and a timer."