title: Detection of proteins on silica-silver core-shell substrates by surface-enhanced Raman spectroscopy.
abstract: We have employed the proposed Silica-Silver Core-Shell (SSCS) SERS-active substrates to detect four model proteins: lysozyme (a protein without chromophore), cytochrome c (a protein with chromophore of heme), fluorescein isothiocyanate (FITC)-anti human IgG (labeled with FITC) and atto610-biotin/avidin (recognition with labeled small molecules). SERS spectra of these proteins and Raman labels on the SSCS substrates show both high sensitivity and reproducibility, which are due to electromagnetic SERS enhancement with additional localization field within closely packed Ag nanoparticles decorated on the SiO(2) nanoparticles and the aggregation of SiO(2)@Ag particles. We have found that the SERS intensities of atto610-biotin/avidin adsorbed on the SSCS substrates are about 20 times stronger than those from Ag plating on Au-decorated substrate. Moreover, the broad surface plasmon resonance (SPR) of the proposed substrates will extend SERS applications to more biological molecules with different laser excitations.
authors.affiliation: State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun 130012, PR China.
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
authors.forename: Xiaoxia
authors.initials: X
authors.lastname: Han
authors.forename: Jingxiu
authors.initials: J
authors.lastname: Yang
authors.forename: Ji
authors.initials: J
authors.lastname: Zhou
authors.forename: Wei
authors.initials: W
authors.lastname: Song
authors.forename: Bing
authors.initials: B
authors.lastname: Zhao
authors.forename: Weiqing
authors.initials: W
authors.lastname: Xu
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Ozaki
mesh_terms: D001360:Avidin / Q000032:analysis; D001710:Biotin / Q000032:analysis; D045304:Cytochromes c / Q000032:analysis / Q000378:metabolism; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D009113:Muramidase / Q000032:analysis / Q000378:metabolism; D012822:Silicon Dioxide / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D013059:Spectrum Analysis, Raman; D020349:Surface Plasmon Resonance; D013499:Surface Properties
chemical_list: D007074:Immunoglobulin G; D001360:Avidin; D012834:Silver; D001710:Biotin; D012822:Silicon Dioxide; D045304:Cytochromes c; D009113:Muramidase