Acid cleavable surface enhanced raman tagging for protein detection.

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Biochemistry

Background:

• Dye conjugation enhances surface-enhanced Raman spectroscopy (SERS) sensitivity for biomolecules.
• Existing methods may face challenges with signal interference or sensitivity limitations.

Purpose of the Study:

• To introduce and validate a novel acid-cleavable SERS tag (ACST) method.
• To demonstrate the effectiveness of ACST for sensitive protein detection using SERS.

Main Methods:

• Development of an ACST prototype using Rhodamine B, an acid-cleavable linker, and a protein-reactive moiety.
• Acid cleavage of ACST tags under mild conditions (1.5% trifluoroacetic acid).
• SERS detection of ACST-tagged bovine serum albumin (BSA).

Main Results:

• Complete acid cleavage of ACST tags was achieved at room temperature.
• Quality SERS spectra were obtained from acid-cleaved ACST-BSA conjugates, unlike intact conjugates dominated by fluorescence.
• Achieved SERS detection sensitivity of ~5 nM for BSA and ~1.5 nM for ACST, with a dynamic range of four orders of magnitude.

Conclusions:

• The ACST method offers a significant improvement in SERS detection sensitivity for biomolecules.
• Separation of the SERS tag moiety after cleavage further enhances sensitivity.
• This cleavable tagging strategy shows potential for reducing protein interference in fluorescence-based detection.