Affordable plasmonic biosensing: democratizing SERS with scalable, field-compatible substrate fabrication

Area of Science:

• Plasmonic biosensing
• Field-deployable diagnostics
• Surface-Enhanced Raman Spectroscopy (SERS)

Background:

• Traditional SERS biosensing faces challenges in field applications due to high costs, complex fabrication, and equipment requirements.
• Existing methods lack the stability and reproducibility needed for point-of-care (PoC) diagnostics.
• There is a need for accessible, cost-effective, and robust SERS substrates for remote and resource-limited environments.

Purpose of the Study:

• To develop a democratized and cost-effective fabrication kit for SERS substrates.
• To enable the local production of sensitive and reproducible SERS biosensors using simple materials and techniques.
• To demonstrate the feasibility of field-deployable SERS for detecting bacteria and pesticides.

Main Methods:

• Developed a low-cost fabrication kit utilizing common materials and electrochemistry.
• Employed battery-powered fabrication for SERS substrate production, independent of a power grid.
• Conducted reproducibility analysis across multiple batches and demonstrated applications in pesticide and bacteria detection.

Main Results:

• The fabrication kit costs $39.54, with consumables at 1.33¢ per test, enabling cost-effective SERS substrate production.
• Consistent plasmonic enhancement and high sensitivity were achieved, with pesticide detection down to 0.1 ppm.
• Successfully identified bacteria, including *Escherichia coli* and *Bacillus subtilis*, and trace levels of pesticides (Thiram, Thiabendazole).

Conclusions:

• The developed SERS fabrication kit offers a democratized, cost-effective solution for field-deployable biosensing.
• This technology overcomes traditional barriers, enabling sensitive and reproducible diagnostics in resource-restricted areas.
• Paired with portable spectrometers, it promises a new era of accessible public health and food safety testing.