Light Sensor Detects Ultra-Low Levels of Traumatic Brain Injury Biomarkers

Researchers at the Beijing Institute of Technology developed a metasurface biosensor chip that detects traumatic brain injury (TBI) biomarkers at concentrations as low as femtograms per milliliter. According to Professor Guangyuan Li, the light-based sensor provides a faster, more sensitive alternative to current time-consuming laboratory methods for diagnosing head injuries.

How does the metasurface biosensor detect brain injury?

The device uses metasurfaces—ultra-thin materials with microscopic etched patterns—to manipulate light with high precision. Professor Guangyuan Li and his team coated a gold metasurface with antibodies designed to target specific TBI biomarkers. When these target molecules bind to the antibodies, the light wavelengths reflected by the surface shift slightly.

This shift allows the sensor to identify the presence of biomarkers even at extremely low concentrations. To verify the technology, the researchers built two separate sensors targeting the glial fibrillary acidic protein (GFAP) and S100 calcium-binding protein β (S100β). The sensors accurately detected wavelength shifts based on biomarker concentration, maintaining sensitivity even when other biomarkers were present in the sample.

Why is femtogram-level sensitivity critical for TBI diagnosis?

Current methods for measuring TBI biomarkers are often slow and involve multiple complex laboratory steps, according to Professor Li. High sensitivity reduces the time between injury and diagnosis, which helps clinicians choose treatment courses faster and provides early warnings for potential complications.

The ability to detect GFAP and S100β at such low levels is part of a broader trend in light-based diagnostics. Similar optical sensors are currently being explored for real-time diabetes monitoring and early cancer diagnosis to increase precision over conventional blood tests.

Where will this technology be used in the future?

The ultimate goal is a point-of-care format that requires only a finger prick of blood. Yunhui Liu, PhD, an associate professor at the Shenzhen Institutes of Advanced Technology, stated this could reduce unnecessary CT scans for low-risk patients while flagging high-risk cases sooner.

Liu noted that this technology could expand biomarker detection to settings where time is critical, including:

• Ambulances during emergency transport.
• Rural clinics with limited laboratory infrastructure.
• Sports venues for immediate concussion screening.
• Hospital emergency departments.

What hurdles remain before clinical adoption?

The technology isn’t ready for the clinic yet. Professor Li’s team must first reduce manufacturing costs for the gold metasurfaces. They are also working on improving fluid handling and packaging to make the sensor practical for medical staff to use.

The final step involves clinical trials. These trials will validate whether the sensor’s performance in a laboratory setting translates to accurate results in real-world patients with varying health profiles.

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