Lab-on-a-bubble surface enhanced Raman indirect immunoassay for cholera

Area of Science:

• Biotechnology
• Nanotechnology
• Analytical Chemistry

Background:

• Cholera toxin (CT) poses a significant public health threat, necessitating sensitive and rapid detection methods.
• Current diagnostic assays, such as lateral flow and magnetic pull-down assays, have limitations in sensitivity or speed.
• Surface-enhanced Raman scattering (SERS) offers a highly sensitive and specific detection modality.

Purpose of the Study:

• To develop a novel, rapid, and sensitive assay for the detection of the cholera toxin beta (β) subunit.
• To introduce a new platform technology, termed "lab on a bubble" (LoB), for antigen detection in solution.
• To evaluate the performance of the LoB assay compared to existing methods.

Main Methods:

• A sandwich assay was designed using buoyant silica microspheres functionalized with anti-CT antibodies.
• Gold nanoparticles, tagged with a Raman reporter and silica-shelled with anti-CT antibodies, were used as signal probes.
• The assay relies on the formation of a buoyant complex that floats to the surface for detection via SERS.

Main Results:

• The developed assay successfully detected the cholera toxin β subunit using a SERS-based "lab on a bubble" approach.
• The assay demonstrated a limit of detection of 1100 ng for the CT β subunit in a buffer system.
• The buoyant nature of the assay components facilitates easy separation and detection.

Conclusions:

• The "lab on a bubble" (LoB) assay represents a promising new platform for rapid antigen detection.
• SERS coupled with buoyant micro/nanoparticles offers advantages in sensitivity and ease of use over conventional methods.
• Further development of the LoB platform could lead to improved diagnostics for various analytes.