title: Bacterial analysis by laser desorption ionization mass spectrometry on amorphous silicon.
abstract: Lipid profiling in nine bacterial species has been accomplished by laser desorption ionization mass spectrometry (LDI-MS) using amorphous silicon (a-Si) thin film with 100 nm thickness. Lipid ions could be generated by LDI on a-Si regardless of ion acquisition modes because of a thermal property of a-Si to govern laser-induced surface heating. In a comparative study of lipid profiling in Bacillus lichemiformis by LDI-MS and matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), LDI-MS on a-Si shows a higher efficiency in lipid and lipopeptide detection than MALDI-MS. A total of 53 peaks of lipid ions generated by LDI on a-Si in both acquisition modes for m/z 400-1200 was 1.6 times more than that detected by MALDI-MS using three organic matrices-2,5-dihydroxybenzoic acid, 1,5-diaminonaphthalene, and 2,4,6-trihydroxyacetophenone monohydrate. Also, the authors demonstrate by mass spectrometry imaging (MSI) that LDI-MS provides high detection coverage through whole sample area. MSI results show the detection yield in LDI on a-Si is 94.8% calculated by counting the number of points detected in the analyte ion signal in a whole spot. It means that reproducible detection of lipid ions by LDI-MS is possible even if laser is randomly irradiated at any position within the bacterial sample area applied on a-Si. Lipid profiling by LDI-MS on a-Si was applied to bacterial differentiation of nine bacterial species conducted by performing principal component analysis. Nine bacterial species are successfully distinguishable from each other by LDI-MS lipid profiling.
authors.affiliation: Center for Nano-Bio Measurement, Korea Research Institute of Standards and Science (KRISS), Daejeon 34113, South Korea and Department of Chemistry, Chungnam National University, Daejeon 34134, South Korea.
authors.forename: Shin Hye
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Chemistry, Chungnam National University, Daejeon 34134, South Korea.
authors.forename: Jeongkwon
authors.initials: J
authors.lastname: Kim
authors.affiliation: Personalized Genomic Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, South Korea and Department of Functional Genomics, University of Science and Technology (UST), Daejeon 34113, South Korea.
authors.forename: Seung-Hyun
authors.initials: SH
authors.lastname: Jo
authors.affiliation: Personalized Genomic Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, South Korea.
authors.forename: Jeong-Hoon
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Center for New Functional Materials, Korea Research Institute of Standards and Science (KRISS), Daejeon 34113, South Korea.
authors.forename: Kyung Joong
authors.initials: KJ
authors.lastname: Kim
authors.affiliation: Center for Nano-Bio Measurement, Korea Research Institute of Standards and Science (KRISS), Daejeon 34113, South Korea.
authors.forename: Sohee
authors.initials: S
authors.lastname: Yoon
mesh_terms: D001407:Bacillus / Q000737:chemistry*; D007834:Lasers; D008055:Lipids / Q000032:analysis*; D013058:Mass Spectrometry / Q000379:methods*; D012825:Silicon
chemical_list: D008055:Lipids; D012825:Silicon