Quantification of Protein Biomarker Using SERS Nano-Stress Sensing with Peak Intensity Ratiometry

Abstract

We report a surface enhanced Raman spectroscopy (SERS) ratiometry method based on peak intensity coupled in a nano-stress sensing platform to detect and quantify biological molecules. Herein, we employed an antibody-conjugated [Formula: see text]-aminothiophenol (ATP) functionalized on a bimetallic-film-over-nanosphere (BMFON) substrate as a sensitive SERS platform to detect human haptoglobin (Hp) protein, which is an acute phase protein and a biomarker for various cancers. Correlation between change in the ATP spectral characteristics and concentration of Hp protein was established by examining the peak intensity ratio at 1572[Formula: see text]cm[Formula: see text] and 1592[Formula: see text]cm[Formula: see text] that reflects the degree of stress experienced by the aromatic ring of ATP during Hp protein–antibody interaction. Development of this platform shows the potential in developing a low-cost and sensitive SERS sensor for the pre-screening of various biomarkers.