Schematic representation showing the mechanism of the selective determination of sodium ions using curcumin functionalised copper nanoparticles (CuC)-based colorimetric probe. Credit: Chandra, N. et al. Sci. Rep. (2022) 12:6247
Researchers have designed a highly sensitive paper-based sensor that can be used to measure and monitor changes in sodium ion levels in human blood serum and urine1.
Sodium ions help to maintain the balance of fluid and electrolytes in the human body. Deviation from normal levels has been linked to disorders such as stroke and kidney problems.
The sensor can be used as a low-cost, point-of-care diagnostic tool, say scientists at the Central University of Kerala in India.
They synthesised curcumin-modified clusters of copper nanoparticles and then coated a specific type of paper with the modified nanoparticles to make the sensor.
The researchers tested the sensor with an artificial urine sample, human blood serum and sodium-ion-based solutions. The colour of the paper-based strips changed from yellow to pale pink and then orange as the concentration of sodium ions in the body fluids and solutions increased.
Such visual detection is an eco-friendly, low cost and easy way to diagnose sodium concentration in urine and sweat, the researchers say.
The strips remained stable after being stored at 4°C for three months. The sensor also selectively detected sodium ions despite the presence of other biological components and ions in the blood serum.
