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Surface Enhanced Raman Spectroscopy Detection of Biomolecules Using EBL Fabricated Nanostructured Substrates
Published on: March 20, 2015
A direct method for detecting proteins in body fluids by Surface-Enhanced Raman Spectroscopy under native conditions
Dan Li1, Zhe Zhang2, Xiaotong Wang3
1College of Pharmacy, Harbin Medical University, No. 157, Baojian Road, Nangang District, Harbin City, Heilongjiang Province, China; Institute of Physics, Guizhou University, No. 2708, South Section of Huaxi Avenue, Guiyang City, Guizhou Province, China.
Abstract:
Surface enhanced Raman spectroscopy (SERS) is widely used in biomolecular detection. However, maintaining the native structure of proteins while obtaining sensitive and reproducible SERS signals of unlabeled proteins remains a challenge. In this study, dichloromethane (DCM) and CaCl2 were used to optimize the aggregation of Ag nanoparticles (AgNPs), and several proteins were analyzed comprehensively. Calcium ions removed citrate ions outside AgNPs, inducing hot spots and achieving high-sensitivity SERS signals of proteins. Furthermore, 20 random samples of 0.5 μg/mL hemoglobin were analyzed by this method. The obtained spectra showed good repeatability and a high quality. Using the peak intensity of DCM as internal parameter, the differences in peak intensities at the same position were analyzed to distinguish different proteins and evaluate changes in protein structure. Subsequently, the protein content in protein mixtures and serum was quantified and a good linear relationship between peak intensity and protein concentration was obtained. This method shows great promise in the fields of food testing and clinical diagnosis.
