Daigou Mizoguchi

Laser Desorption/Ionization Mass Spectrometry (LDI-MS) of Lipids with Iron Oxide Nanoparticle-Coated Targets.

Iron oxide nanoparticle (NP)-coated target plates were employed for the direct detection and analysis of low molecular weight lipids by laser desorption/ionization (LDI) mass spectrometry (MS). We have demonstrated that the use of the iron oxide NP-coated target provides a simple, direct, and rapid detection method for lipid standards and epidermal surface lipids without any cumbersome sample pretreatment as well as mass spectra that are free of background matrix peaks. Lipid standards (1-stearoyl-sn-glycero-3-phosphocholine, 1,2-dioleoyl-sn-glycerol, 1-palmitoyl-2-oleoyl-3-linoleoyl-rac-glycerol, 1,2-distearoyl-sn-glycero-3-phosphocholine) were detected as either protonated or cationated species. Clean MS/MS spectra for each lipid were also successfully obtained. Pre-MS surface cleaning of the target plates with UV-ozone treatment successfully removed organic contaminants that would interfere with the mass spectra especially in the low molecular weight region. Preliminary application of the presented target plate to the detection of endogenous lipids in latent fingerprints showed promising results and for potential use in the visualization and chemical composition determination of latent fingerprints by nanoparticle assistance.

Fabrication and Optical Properties of Gold Nanorod-Polymer Composite Films

Gold nanorods are fascinating nanomaterials for electro-optical applications in nanotechnology, but the basic drawbacks have been thermally unstable and the difficulty in incorporating into the film. In this study, we have developed a simple and highly-reproducible method for large-scale fabrication of composite films consisting of gold nanorods and an organic polymer. The film could be easily casted for more than 10 × 10-cm2 area and the shape (that is, optical characteristic) of gold nanorods could withstand up to ca. 200°C. The composite film was also sensitive to the dielectric constant of the surrounding medium.