In order to confirm that a patient presenting with a heart attack has in fact had one, doctors typically use bulky, expensive lab equipment ... which isn't always available to clinicians in developing nations or rural locations. That's why scientists from Korea's Pohang University of Science and Technology have created a simple thermometer-like device that reportedly does the job.

When the cardiac muscles are damaged – such as in the course of a heart attack – the concentration of a protein called troponin increases in the bloodstream. Microresonators, surface acoustic wave sensors and electrochemical sensors are among the devices usually used to measure troponin concentrations, although they're generally costly and non-portable. A gadget known as a lateral flow immunoassay is one less-bulky alternative, although it doesn't provide very precise readings.

Prof. Sangmin Jeon and his team instead looked at making something that worked like a simple alcohol or mercury thermometer.

To use it, a sample of the patient's blood serum is placed in a glass vial, along with a solution containing troponin antibody-functionalized dendritic platinum nanoparticles – these particles capture even very small amounts of troponin present in the serum. Hydrogen peroxide is then also added, and the vial is capped.

In a chemical reaction, the troponin causes the hydrogen peroxide to dissociate into water and oxygen, in turn causing the pressure inside the vial to increase. When a glass capillary tube containing ink is inserted through the vial's cap, that pressure causes the ink to rise within the tube. As with a thermometer, users can then just read the numeric markings on the tube, at the point to which the ink rises.

Along with its use in poor countries and remote locations, the device could conceivably also be used on-location by first responders.

A paper on the research was recently published in the journal Analytical Chemistry.