Analytical Biochemistry 2009-08-01

Protein separation and identification using magnetic beads encoded with surface-enhanced Raman spectroscopy.

Bong-Hyun Jun, Mi Suk Noh, Gunsung Kim, Homan Kang, Jong-Ho Kim, Woo-Jae Chung, Min-Soo Kim, Yong-Kweon Kim, Myung-Haing Cho, Dae Hong Jeong, Yoon-Sik Lee

Index: Anal. Biochem. 391(1) , 24-30, (2009)

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Abstract

This article presents a prototype of a surface-enhanced Raman spectroscopy (SERS)-encoded magnetic bead of 8mum diameter. The core part of the bead is composed of a magnetic nanoparticle (NP)-embedded sulfonated polystyrene bead. The outer part of the bead is embedded with Ag NPs on which labeling molecules generating specific SERS bands are adsorbed. A silica shell is fabricated for further bioconjugation and protection of SERS signaling. Benzenethiol, 4-mercaptotoluene, 2-naphthalenethiol, and 4-aminothiophenol are used as labeling molecules. The magnetic SERS beads are used as substrates for protein sensing and screening with easy handling. As a model application, streptavidin-bound magnetic SERS beads are used to illustrate selective separation in a flow cytometry system, and the screened beads are spectrally recognized by Raman spectroscopy. The proposed magnetic SERS beads are likely to be used as a versatile solid support for protein sensing and screening in multiple assay technology.