Highly sensitive protein detection using recombinant spores and lateral flow immunoassay.

Area of Science:

• Biotechnology
• Biosensors
• Assay Development

Background:

• Lateral flow immunoassays (LFIs) are widely used for rapid detection.
• Gold nanoparticles (AuNPs) improve LFI sensitivity but have limitations.
• Spore-based surface display is effective for enzyme immobilization and vaccine development.

Purpose of the Study:

• To enhance the sensitivity of LFIs using recombinant spores.
• To develop a rapid protein detection kit combining streptavidin-displayed spores and LFI.
• To explore the use of fluorescent recombinant spores for detection.

Main Methods:

• Engineered recombinant spores displaying streptavidin on their surface.
• Combined spore-based signal amplification with LFI using AuNPs as reporters.
• Detected model proteins (β-galactosidase and eGFP) using the developed assay.
• Utilized fluorescence microscopy for eGFP detection.

Main Results:

• Achieved a detection limit of 10^-15 mol for β-galactosidase, a 1000-fold improvement over conventional LFI (10^-12 mol).
• Demonstrated naked-eye detection using AuNPs as colorimetric signals.
• Detected eGFP with a limit of 10^-16 mol using fluorescence microscopy.
• The enhanced LFI maintained the advantages of traditional LFIs.

Conclusions:

• Recombinant spores significantly amplify signals in LFIs, drastically improving detection limits.
• The developed spore-based LFI assay offers a highly sensitive and rapid method for protein detection.
• Fluorescent recombinant spores provide an alternative detection strategy with excellent sensitivity.