Minimally Invasive Probe Measures Key Metabolic Markers Simultaneously

Glucose trends guide diabetes care, while lactate can signal sepsis or tissue hypoxia, and ethanol levels matter for intoxication and brain injury management. Delays in obtaining these values can hinder timely interventions and increase risk. To help address this challenge, a newly introduced fiber-based technology aims to measure glucose, lactate, and ethanol simultaneously at the point of care.

Researchers at The University of Texas at Austin have developed a mid-infrared fiber probe that tracks three biomarkers in real time within tissue. The device is the smallest of its kind, measuring 1.1 millimeters in diameter, which supports minimally invasive use. It is designed to provide faster, more comprehensive metabolic insight for clinicians.

The probe integrates two silver halide optical fibers inside a polyetheretherketone tube and is encased by a semi-permeable membrane. One fiber features an angled tip to deliver and collect light, while the second is gold-coated to function as a mirror. The membrane prevents direct contact with tissue, improving biocompatibility and reducing interference from larger molecules such as proteins.

A quantum cascade laser (QCL) supplies mid-infrared light that interacts with local molecules. Each target—glucose, lactate, and ethanol—absorbs light at specific wavelengths, generating a spectral signature that enables quantification without altering the compounds. This approach allows continuous, in situ measurement and avoids disturbing the local tissue environment.

Conventional microdialysis requires inserting a probe, collecting fluid samples, and processing them offline, which delays results and is labor-intensive. Such delays can limit rapid response to evolving metabolic crises. By providing real-time data directly in tissue, the fiber probe is intended for hospital use and other medical settings, with potential adaptation to a wearable device. The work is published in Nature Communications (2026) and was demonstrated using ex vivo human skin. The university has filed a patent application.

“Real-time monitoring of biomarkers like glucose, lactate and ethanol is essential for understanding metabolic health and guiding treatment decisions in critical care settings,” said Tanya Hutter, professor in the Cockrell School of Engineering's Walker Department of Mechanical Engineering and lead author  of the study. "Our compact fiber probe offers a unique solution to measure these compounds simultaneously, providing a more complete picture of the metabolic state."

“Unlike microdialysis, it doesn't disturb the local tissue environment, so it is more representative of what's actually happening inside the tissue,” said Tse-Ang Lee, a Ph.D. student in Hutter's lab and a co-author on the new paper.

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