Sulfate-Directed Silver Dendrites with Enhanced Stability for Ultrasensitive SERS-Based Therapeutic Drug Monitoring

Area of Science:

• Materials Science
• Analytical Chemistry
• Nanotechnology

Background:

• Silver-based surface-enhanced Raman spectroscopy (SERS) substrates provide high sensitivity but are limited by poor long-term stability due to oxidation.
• Oxidative degradation restricts the practical application of conventional SERS substrates in real-world scenarios.

Purpose of the Study:

• To develop oxidation-resistant SERS substrates with enhanced stability and reproducibility.
• To establish a reliable platform for sensitive detection of analytes in complex matrices.

Main Methods:

• Synthesis of sulfate-directed silver dendrites (s-AgDs) utilizing sulfate ions to promote anisotropic growth and form a protective sulfate layer.
• Characterization of s-AgDs morphology, stability, and SERS performance over extended periods.
• Demonstration of s-AgDs utility for detecting clinically relevant drugs in aqueous and blood plasma samples.

Main Results:

• s-AgDs exhibited suppressed surface oxidation and maintained robust SERS performance for over seven months under ambient conditions.
• The dendritic morphology of s-AgDs resulted in high hot-spot density, enabling sub-picomolar sensitivity.
• Successful detection of five clinically relevant drugs in aqueous and blood plasma matrices with minimal pretreatment and high reproducibility.

Conclusions:

• Sulfate-directed silver dendrites (s-AgDs) represent a stable, reproducible, and oxidation-resistant SERS platform.
• The developed s-AgDs are suitable for sensitive and reliable detection of analytes in complex biological samples.
• This technology holds significant potential for point-of-care therapeutic drug monitoring applications.