A SERS-based lateral flow assay for the stroke biomarker S100-β

Area of Science:

• Biomarker detection
• Nanotechnology applications
• Assay development

Background:

• S100-β is a crucial protein biomarker for stroke diagnosis.
• Existing detection methods often lack the sensitivity required for early diagnosis.
• Lateral flow assays (LFAs) offer rapid, point-of-care testing potential.

Purpose of the Study:

• To develop a highly sensitive SERS-based LFA for quantitative S100-β analysis.
• To improve detection limits for S100-β compared to existing methods.
• To utilize gold nanoparticles (GNPs) functionalized with Raman reporters for enhanced signal.

Main Methods:

• A SERS-based LFA was designed using 5,5'-dithiobis-2-nitrobenzoic acid (DTNB) functionalized gold nanoparticles (GNPs) as SERS tags.
• The assay quantifies S100-β by monitoring the Raman signal intensity at 1332 cm⁻¹.
• Optimized assay conditions were established for S100-β detection.

Main Results:

• The SERS-LFA demonstrated superior performance compared to bare GNPs in LF strips.
• The assay achieved a wide linear range for S100-β detection from 1 pg·mL⁻¹ to 40 ng·mL⁻¹.
• An ultra-low limit of detection of 0.14 pg·mL⁻¹ was achieved, three times lower than colorimetric or fluorimetric methods.

Conclusions:

• The developed SERS-LFA provides a highly sensitive and quantitative method for S100-β detection.
• This assay holds promise for early and accurate stroke diagnosis.
• The use of DTNB-functionalized GNPs significantly enhances assay sensitivity and performance.