A salivary urea sensor based on a microsieve disposable gate AlGaN/GaN high electron mobility transistor

Area of Science:

• * Biomedical Engineering
• * Materials Science
• * Analytical Chemistry

Background:

• * Saliva contains abundant biomarkers for non-invasive testing.
• * Saliva impurities often necessitate pre-processing, limiting convenient daily use of biosensors.
• * Existing high electron mobility transistor (HEMT) biosensors face signal interference from saliva's charged impurities.

Purpose of the Study:

• * To develop a HEMT biosensor integrated with a micro-sieve for improved saliva analysis.
• * To address signal interference caused by impurities in saliva for HEMT-based biosensors.
• * To enable accurate, real-time detection of specific markers in saliva.

Main Methods:

• * Fabricated a disposable-gate AlGaN/GaN HEMT biosensor.
• * Integrated a micro-sieve as a pre-treatment unit to remove large particles from saliva.
• * Evaluated sensor performance using urea detection in phosphate-buffered saline (PBS) and artificial/human saliva.

Main Results:

• * The HEMT biosensor demonstrated excellent linearity (R² = 0.9977) and high sensitivity (6.552 μA dec⁻¹) for urea sensing across a wide concentration range (1 fM to 100 mM).
• * The micro-sieve integration maintained high sensitivity in artificial saliva compared to sensors without the sieve.
• * Successful direct detection of urea in human saliva was achieved, validating the device's real-world applicability.

Conclusions:

• * The micro-sieve effectively removes impurities, enhancing the accuracy of HEMT biosensors for saliva analysis.
• * The integrated HEMT biosensor offers a promising platform for sensitive and real-time detection of biomarkers in saliva.
• * This technology has significant potential for rapid, non-invasive diagnostic applications using saliva.