Hand-held Raman spectrometer-based flexible plasmonic biosensor for label-free multiplex urinalysis

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Materials Science

Background:

• Urinalysis is a key non-invasive method for health assessment.
• Surface-enhanced Raman scattering (SERS) offers potential for sensitive urine analyte detection.
• Existing methods may lack the simplicity and portability for widespread use.

Purpose of the Study:

• To develop a wearable diaper sensor for label-free urine biomolecule detection using SERS.
• To evaluate the sensor's performance in identifying urea, creatinine, and bilirubin.
• To demonstrate the sensor's utility for non-invasive disease monitoring.

Main Methods:

• Fabrication of a flexible, raspberry-shaped gold (Au) substrate on silicon wafer for SERS.
• Integration of the SERS substrate into a wearable diaper sensor.
• Utilizing a handheld Raman spectrometer for signal acquisition.
• Label-free detection and quantification of target biomolecules in urine.

Main Results:

• The SERS sensor demonstrated excellent uniformity and stability.
• High sensitivities were achieved for urea (4.17 × 10⁻³ M), creatinine (5.90 × 10⁻⁶ M), and bilirubin (1.38 × 10⁻⁷ M).
• The sensor successfully monitored biomolecules at diagnostic thresholds.

Conclusions:

• The developed wearable diaper SERS sensor offers a flexible, portable, and multifunctional platform for urinalysis.
• This technology facilitates simple, label-free identification of key urine biomarkers.
• The sensor holds promise for non-invasive disease diagnosis and continuous medical monitoring.