title: microAg particle-based molecular sensing/recognition via surface-enhanced Raman spectroscopy.
abstract: In this study, we demonstrate that powders of commercially available 2-microm-sized Ag (microAg) can be used as a core material for constructing molecular sensing/recognition units operating via surface-enhanced Raman scattering (SERS). This is possible because microAg powders are very efficient substrates for both the infrared and Raman-spectroscopic characterization of molecular adsorbates prepared in a similar manner on silver surfaces. The Raman spectrum of organic monolayers on powdered silver is a SERS spectrum. The agglomeration of microAg particles in a highly concentrated buffer solution could be prevented by the deposition of polar molecules like 1,4-phenylenediisocyanide (1,4-PDI), and mixed self-assembled monolayers of 1,4-PDI and N-(+)-biotinyl-6-aminocaproic acid on microAg particles were then confirmed via the SERS of 1,4-PDI to selectively recognize the avidin arrays formed on a separate biotinylated substrate. According to a dose response curve, avidin at >10(-6)g/mL could be easily identified by the present method. In addition, the non-specific adsorption of microAg particles was found to be negligibly small, probably because the Ag particles were too heavy to be retained on organic substrates solely by non-specific interaction.
authors.affiliation: Laboratory of Intelligent Interfaces, School of Chemistry, Seoul National University, Seoul 151-742, Republic of Korea. kwankim@snu.ac.kr
authors.forename: Kwan
authors.initials: K
authors.lastname: Kim
authors.forename: Nam Hoon
authors.initials: NH
authors.lastname: Kim
authors.forename: Hyoung Kun
authors.initials: HK
authors.lastname: Park
mesh_terms: D001360:Avidin / Q000032:analysis* / Q000276:immunology; D015374:Biosensing Techniques / Q000379:methods*; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D007118:Immunoassay / Q000379:methods*; D008863:Microspheres; D010316:Particle Size; D012834:Silver / Q000737:chemistry*; D013059:Spectrum Analysis, Raman / Q000379:methods*; D020349:Surface Plasmon Resonance / Q000379:methods*
chemical_list: D020099:Coated Materials, Biocompatible; D001360:Avidin; D012834:Silver