A flexible plasmonic SERS hydrogel patch for metabolite sensing on bio-interfaces

Area of Science:

• Materials Science and Engineering
• Biomedical Engineering
• Analytical Chemistry

Background:

• Growing demand for real-time, non-invasive monitoring of biochemical molecules necessitates advanced flexible sensing materials.
• Rigid Surface-Enhanced Raman Spectroscopy (SERS) substrates lack mechanical compatibility for dynamic biological surfaces.
• Need for adaptable SERS platforms for applications in skin and neural tissue monitoring.

Purpose of the Study:

• To develop a flexible SERS hydrogel patch for label-free detection of metabolites at bio-interfaces.
• To enhance mechanical compatibility and conformal adhesion for dynamic biological surfaces.
• To demonstrate in situ metabolite monitoring capabilities for potential biomedical applications.

Main Methods:

• Integration of a self-assembled silver nanoparticle film with an ultrathin polyvinyl alcohol (PVA) hydrogel layer.
• Fabrication of a flexible SERS hydrogel patch for conformal adhesion to biological tissues.
• Utilized SERS for label-free detection of metabolites, including glucose, uric acid, and urea.

Main Results:

• The SERS hydrogel patch demonstrated good plasmonic enhancement, mechanical durability, and SERS stability.
• Achieved label-free detection of metabolites within 6 minutes of analyte exposure.
• Detected glucose down to 1 μM, uric acid to 50 μM, and urea to 1 mM.
• Successful ex vivo demonstration on porcine brain and muscle tissues.

Conclusions:

• The flexible SERS hydrogel patch is a viable platform for in situ metabolite monitoring at bio-interfaces.
• The developed patch offers a promising solution for non-invasive biochemical sensing in dynamic biological environments.
• Potential applications include brain-machine interfaces and implantable sensors requiring real-time biochemical feedback.