Au@1,4-benzenedithiol@Au core-shell {SERS} immunosensor for ultra-sensitive and high specific biomarker detection

By Wan, Liping; Zheng, Rongrong; Xiang, Juan
Published in Vibrational Spectroscopy NULL 2017

Abstract

Abstract A surface enhanced Raman scattering (SERS)-based immunosensor based on functional core-shell nanoparticles (Au@1,4-benzenedithiol@Au NPs) was developed for ultra-sensitive and high specific tumor marker detection. The engaged rigid dithiol molecule 1,4-benzenedithiol (1,4-BDT), which was used as a Raman reporter as well as a core-shell gap maker, connected the Au core and shell, facilitated the thickness controls of the shell and the core-shell gap. The thin Au shell in Au@1,4-BDT@Au prevented the dissociation of 1,4-BDT and its nonspecific interactions with co-existing proteins in complicated biological environment, which significantly improve the stability and sensitivity of the probe. To verify the validation of the Au@1,4-BDT@Au {SERS} immunosensor, a well-known prostate cancer marker, f-PSA antigen, was detected. As expected, the non-specific adsorption of co-existing proteins was significantly reduced, and the detection sensitivity of f-PSA was greatly enhanced with a limit of detection of 2.0 pg/mL. The linear correlation with the logarithm of concentration in wider range from 10 pg/mL to 10 ng/mL was achieved. The analysis of f-PSA-spiked human serum samples revealed that the method had high accuracy. Therefore, the dithiol Raman reporter-encoded Au@Au core-shell structure-based immunosensor is promising for the ultra-sensitive and high specific tumor marker detections.

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