Rapid melatonin test can help astronauts and others easily monitor their biological rhythm

A simple test developed at Washington State University could eventually allow astronauts and others in round-the-clock occupations to monitor their biological rhythms in just minutes using a drop of blood, a paper test strip, and a smartphone-based reader. An interdisciplinary team of WSU researchers created an inexpensive, 15-minute test using fluorescent nanoparticles to measure melatonin levels, which rise and fall along with a person's internal biological clock.