Bioinspired Disordered Flexible Metasurfaces for Human Tear Analysis Using Broadband Surface-Enhanced Raman...

Area of Science:

• Nanotechnology
• Biomedical Engineering
• Spectroscopy

Background:

• Flexible surface-enhanced Raman scattering (SERS) is promising for point-of-care diagnostics.
• Traditional flexible SERS devices lack reliable broadband enhancement due to periodic or random nanostructures.
• Substrate interference is a significant challenge in flexible SERS applications.

Purpose of the Study:

• To develop a flexible SERS metasurface with tunable, broadband enhancement.
• To address the limitations of existing flexible SERS technologies for practical biosensing.
• To create a reliable platform for non-invasive biosensing of biomarkers.

Main Methods:

• Fabrication of a flexible metasurface (flex-MS) using bioinspired quasi-(dis)ordered metal-insulator-metal (MIM) nanostructures.
• Design of MIM nanostructures to create spectrally variable, spatially controlled electromagnetic hotspots.
• Blocking of background Raman signals from the substrate using the MIM design.

Main Results:

• The flex-MS exhibits broadband yet tunable SERS enhancement.
• Quasi-(dis)ordering of nanostructures effectively controls SERS enhancement profiles.
• Demonstrated successful detection of human tear uric acid (25-150 μM) ex vivo.
• Ex vivo results showed good agreement with a commercial enzyme-based assay.

Conclusions:

• Bioinspired quasi-(dis)ordered nanostructures provide a reliable method for tunable broadband SERS.
• The developed flex-MS effectively localizes signals and mitigates substrate interference.
• This technology holds potential for non-invasive, point-of-care diagnostic applications.