SERS biodetection using gold-silica nanoshells and nitrocellulose membranes

Area of Science:

• Biotechnology
• Analytical Chemistry
• Nanotechnology

Background:

• Sensitive detection of biological antigens is crucial for diagnostics.
• Existing methods often require larger sample volumes and are time-consuming.
• Developing rapid and reproducible bioassays remains a key challenge.

Purpose of the Study:

• To develop a rapid, reproducible, and easy-to-execute surface-enhanced Raman scattering (SERS) bioassay.
• To enable detection of low volumes and total amounts of biological antigens.
• To create a versatile platform for potential multiplexed analyte detection.

Main Methods:

• Developed a "half-sandwich" assay utilizing a nitrocellulose (NC) membrane for analyte capture.
• Employed gold-silica nanoshells functionalized with a mixed monolayer for SERS probe construction.
• Modified nanoshells with poly(ethylene glycol) (PEG)-conjugated Raman-active chromophores and antibodies via (ortho-pyridyl) disulfide-PEG-succinimidyl ester.

Main Results:

• Achieved capture of subnanogram analyte amounts from as little as one microliter of sample.
• Generated SERS signals proportional to the amount of antigen present on the NC membrane.
• Demonstrated detection of total antigen amounts as low as 1.25 ng in specific cases.

Conclusions:

• The developed SERS method offers a rapid and sensitive approach for biological antigen detection.
• The assay's performance is reproducible and adaptable for various antigens.
• This technology holds potential for multiplexed detection applications in diagnostics and research.