Single-Use Sensor Strip Similar to Hand-Held Glucometer Detects Cerebrospinal Fluid Leaks

Researchers from the University of Florida (Gainesville, FL, USA) and Yang Ming-Chiao Tung University (Taipei, Taiwan) have been developing rapid clinical testing for CSF leaks after trauma, surgery, tumors, and other defects are vital, because such leaks can cause life-threatening conditions, such as meningitis and intercranial infection. Cerebrospinal fluid is present in the brain and spinal cord and provides critical physiological functions, such as shock absorption and waste removal. CSF directly links extracranial space to subarachnoid space, a compartment within which are the major cerebral blood vessels. In addition to trauma, surgery and congenital defects, CSF leaks are likely to occur because of obesity, high intercranial pressure, and obstructive sleep apnea. Cerebrospinal leaks can come out through the nose or the ears.

Detecting such leaks using primary conventional methods, such as immunofixation electrophoresis (IFE) and enzyme-linked immunosorbent assay (ELISA) require hours or days to turn around results. Secondary methods, such as optical techniques that rely on MRI, often fail to identify the specific leak site. The researchers collected nine human clinical samples and introduced the test fluid into a small liquid channel on the tip of the sensor strips. The liquid channel held electrodes, which contained antibodies on the surface specific to proteins found only in human cerebrospinal fluid. Once the test fluid was inserted into the liquid channel, a few short electrode pulses were sent through the electrodes. The circuit board then analyzed the signal and produced a four-digit number that correlates to the concentration of the protein, called beta-2-transferrin, found in CSF.

The researchers were able to detect beta-2-transferrin in the fluid sample even when other proteins and salts were present and from samples across different patients. The researchers used similar technology to detect proteins in SARS-CoV2, the virus that causes COVID-19. Their next phase of research will focus on detecting various cancer and heart disease biomarkers.

"We were surprised to find out that our detection method could not only provide the result within one second, but our detection limit was also a lot more sensitive for a very diluted concentration than existing detection methods," said study co-author Minghan Xian.

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University of Florida 
Yang Ming-Chiao Tung University