Glowstick-inspired smartphone-readable reporters for sensitive, multiplexed lateral flow immunoassays

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Diagnostics

Background:

• The COVID-19 pandemic amplified the need for sensitive, cost-effective point-of-care (POC) diagnostic platforms.
• Lateral flow assays (LFAs) are crucial POC screening tools, but often require sensitive reporters and advanced readers.
• Existing methods face limitations in sensitivity, cost, and accessibility for widespread POC applications.

Purpose of the Study:

• To develop a novel, highly sensitive, and cost-effective LFA platform utilizing chemical excitation.
• To replace traditional optical excitation with a simpler, more accessible method for POC diagnostics.
• To demonstrate the platform's capability for multiplexed detection using smartphone readability.

Main Methods:

• Developed a "Glow LFA" platform employing standard fluorescent nanoparticle reporters.
• Utilized peroxyoxalate chemistry from inexpensive glowsticks for chemical excitation of fluorescent particles.
• Employed unmodified smartphones for reading the visible light emission from the chemi-excited particles.
• Validated the platform using human chorionic gonadotropin (hCG) as a model analyte and SARS-CoV-2 nucleoprotein.

Main Results:

• Achieved a limit of detection (LoD) of 39 pg/mL for hCG, over ten times more sensitive than standard gold nanoparticle LFAs.
• Successfully detected SARS-CoV-2 nucleoprotein at 100 pg/mL in nasal swab extract.
• Demonstrated multiplexed detection of three analytes (red, green, blue fluorescent reporters) on a single LFA strip using a smartphone camera.

Conclusions:

• The Glow LFA platform offers enhanced sensitivity, simplicity, and cost-effectiveness for POC diagnostics.
• Smartphone-readability and chemical excitation make this platform highly accessible for various diagnostic applications.
• The demonstrated multiplexing capability positions Glow LFA as a promising tool for advanced, multi-analyte POC testing.