Multiplexed lateral flow immunoassays using high photostability gap-enhanced Raman nanotags: Highly sensitive, rapid,...

Area of Science:

• Analytical Chemistry
• Biomedical Engineering
• Biotechnology

Background:

• Accurate point-of-care tests (POCTs) are crucial for early diagnosis of diseases.
• Current lateral flow immunoassays (LFIA) often lack sensitivity and quantitative accuracy.
• There is a need for rapid, multiplexed diagnostic tools for infectious diseases and myocardial injury.

Purpose of the Study:

• To develop a sensitive and multiplexed POCT using surface-enhanced Raman scattering (SERS).
• To integrate gap-enhanced Raman tags (GERTs) for enhanced signal and photostability.
• To achieve simultaneous detection of multiple biomarkers for improved diagnostics.

Main Methods:

• Developed a SERS-based LFIA incorporating ultrahigh photostability GERTs.
• Utilized Raman comprehensive full-spectrum analysis and portable Raman detectors.
• Validated the assay for cardiac troponin I (cTnI), SARS-CoV-2 spike protein (RSSP), influenza A (FluA), and influenza B (FluB) detection.

Main Results:

• Achieved a detection limit of 0.65 pg/mL for cTnI, an order of magnitude more sensitive than fluorescent LFIAs.
• Demonstrated 2-3 orders of magnitude sensitivity improvement compared to colloidal gold for viral detection.
• Enabled simultaneous detection of RSSP, FluA, and FluB on a single test line.
• Obtained results within 15 minutes using a portable Raman detector.

Conclusions:

• The developed GERTs-based LFIA offers rapid, ultrasensitive, and quantitative detection capabilities.
• This method addresses the limitations of conventional LFIAs for critical conditions like myocardial infarction.
• The technology facilitates the development of advanced POCTs for clinical and analytical chemistry applications.