Biomaterials scientists from Penn State, University Park, PA, have developed a new, inexpensive method for detecting salt in sweat or other bodily fluids. The fluorescent sensor, derived from citric acid molecules, is highly sensitive and highly selective for chloride, the key diagnostic marker in cystic fibrosis.

Jian Yang, professor of biomedical engineering, is collaborating with Penn State electrical engineer professor Zhiwen Liu to build a handheld device that measures the salt concentrations in sweat. A mobile device could be especially useful in developing countries where people have limited access to expensive analytical equipment.

Yang's material can also differentiate chloride from bromide, another salt that interferes with the results of traditional clinical laboratory tests.

Beyond cystic fibrosis, the researchers say that the platform can also be used to detect other diseases that display abnormal concentrations of chloride, such as metabolic alkalosis, Addison's disease, and amyotrophic lateral sclerosis.