Label-Free Highly Sensitive Detection of Proteins in Aqueous Solutions Using Surface-Enhanced Raman Scattering

• Published in: Analytical chemistry (Washington) Vol. 81; no. 9; pp. 3329 - 3333
• Main Authors: Han, Xiao X, Huang, Genin Gary, Zhao, Bing, Ozaki, Yukihiro
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.05.2009
• Subjects: Analytical chemistry; Aqueous solutions; Chemistry; Enzymes - analysis; Exact sciences and technology; Hydrogen-Ion Concentration; Proteins; Proteins - analysis; Reproducibility of Results; Scattering; Sensitivity and Specificity; Silver - chemistry; Solutions; Spectrophotometry, Ultraviolet; Spectrum Analysis, Raman; Staining and Labeling; Sulfates - chemistry; Surface Properties; Time Factors; Water - chemistry; Trace analysis; Enzyme; Sulfates; Avidin; Protein; Glycosylases; Sensitivity; Reproducibility; Glycosidases; Detection limit; Surface Enhanced Raman Spectrometry; Hemoglobin; Hydrolases; Qualitative analysis; Pretreatment; Aqueous solution; Lysozyme; Quantitative analysis
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac900395x

We detected concentration-dependent surface-enhanced Raman scattering (SERS) spectra of several label-free proteins (lysozyme, ribonuclease B, avidin, catalase, and hemoglobin) for the first time in aqueous solutions. Acidified sulfate was used as an aggregation agent to induce high electromagnetic enhancement in SERS. Strong SERS spectra of simple and conjugated protein samples could easily be accessed after the pretreatment with the aggregation agent. The detection limits of the proposed method for lysozyme and catalase were as low as 5 μg/mL and 50 ng/mL, respectively. This detection protocol for label-free proteins has combined simplicity, sensitivity, and reproducibility and allows routine qualitative and relatively quantitative detections. Thus, it has great potential in practical high-throughput protein detections.