A new and cheaper way to detect salt concentrations in body fluids has been developed by biomaterial scientists at Penn State. With the help of citric acid-based fluorescent sensor, this development allows a more inexpensive method to detect chlorides – the main diagnostic marker in cystic fibrosis.
Biomedical engineering professor Jian Yang states that their method uses the natural molecule citrate that is important for healthier bones. He adds that besides bone health, salt concentrations on sweat may be connected to other health conditions.
In addition to being low cost, Professor Yang’s chloride sensor is much more sensitive over a wide range of chemicals against other known detection methods. Bromide, another salt compound that throw-off clinical lab tests, can also be detected using Yang’s fluorescent sensor. Also, the presence of citrate on the sensor means chloride and bromide can now distinguished in bodily fluids. Professor Yang’s group is currently in development of a new standard for disease diagnosis through bromide detection.
With developing countries in mind, Yang is now working with Zhiwen Liu, a Penn State electrical engineering professor, to make his sensor portable. The idea is to build a citrate-based salt concentration sensor that can work only with a cellphone. This means no other pricey laboratory equipment is needed which could be a problem if Yang’s sensor is to be implemented in poor countries.
Liu said that their aim is to develop a low cost device that can be automated. “[It] requires no titration by trained staff or expensive instrumentation as in hospitals,” Liu adds. He hopes that the device would provide fast and almost instantaneous result.
Compared with gold standard sweat test lab tests, Yang’s sensor provided similar results. The results of this test were published in a Chemical Science article entitled “Citrate-based fluorescent materials for low-cost chloride sensing in the diagnosis of Cystic Fibrosis.”
Cystic fibrosis occurs in 1 in 2,500 to 3,500 white newborns making it one of the more common genetic diseases in the United States. For other ethnic groups like African Americans and Asian Americans, the numbers are 1 in 17,000 and 1 in 31,000 respectively. This data is provided by the U.S. National Library of Medicine.
Pulmonary specialist Robert Vender confirms that all patients being diagnosed for cystic fibrosis undergoes sweat testing. “To date, measurements of sweat chloride — in millimoles per liter — are only used for diagnostic purposes. However, given the recent scientific and medical advances in CF patient-directed therapy and the development and FDA approval of therapies specifically designed to modify cystic fibrosis transmembrane conductance regulator protein function, serial measurements of sweat chloride may have potential as a therapeutic surrogate indicator of drug effect and is currently measured in many pharmaceutical-industry sponsored studies as a response to these novel treatments.” Dr. Vender works for the Penn State Health Milton S. Hershey Medical Center and has been treating patients with cystic fibrosis for years. He adds, however, that the link between the presence of sweat chloride and actual outcomes such as improved lung function is still a subject of a number of researches.
“Our citrate-based platform for designing fluorescent sensors provides us with great versatility in tailoring sensors to specific applications, “ said Jimin Kim, a Penn state graduate student and one of the lead authors of Yang’s research. Kim hopes that this is just the beginning of the development of more sensors with interesting uses.
More information can be found at: Penn State.