title: Evaluation of biomolecular distributions in rat brain tissues by means of ToF-SIMS using a continuous beam of Ar clusters.
abstract: Time-of-flight secondary ion mass spectrometry (ToF-SIMS) provides detailed chemical structure information and high spatial resolution images. Therefore, ToF-SIMS is useful for studying biological phenomena such as ischemia. In this study, in order to evaluate cerebral microinfarction, the distribution of biomolecules generated by ischemia was measured with ToF-SIMS. ToF-SIMS data sets were analyzed by means of multivariate analysis for interpreting complex samples containing unknown information and to obtain biomolecular mapping indicated by fragment ions from the target biomolecules. Using conventional ToF-SIMS (primary ion source: Bi cluster ion), it is difficult to detect secondary ions beyond approximately 1000 u. Moreover, the intensity of secondary ions related to biomolecules is not always high enough for imaging because of low concentration even if the masses are lower than 1000 u. However, for the observation of biomolecular distributions in tissues, it is important to detect low amounts of biological molecules from a particular area of tissue. Rat brain tissue samples were measured with ToF-SIMS (J105, Ionoptika, Ltd., Chandlers Ford, UK), using a continuous beam of Ar clusters as a primary ion source. ToF-SIMS with Ar clusters efficiently detects secondary ions related to biomolecules and larger molecules. Molecules detected by ToF-SIMS were examined by analyzing ToF-SIMS data using multivariate analysis. Microspheres (45 μm diameter) were injected into the rat unilateral internal carotid artery (MS rat) to cause cerebral microinfarction. The rat brain was sliced and then measured with ToF-SIMS. The brain samples of a normal rat and the MS rat were examined to find specific secondary ions related to important biomolecules, and then the difference between them was investigated. Finally, specific secondary ions were found around vessels incorporating microspheres in the MS rat. The results suggest that important biomolecules related to cerebral microinfarction can be detected by ToF-SIMS.
authors.affiliation: Department of Material and Life science, Seikei University, 3-3-1, Kichijyoji-kitamachi, Musashino-shi, Tokyo 180-8633, Japan.
authors.forename: Shusuke
authors.initials: S
authors.lastname: Nakano
authors.affiliation: Department of Material and Life science, Seikei University, 3-3-1, Kichijyoji-kitamachi, Musashino-shi, Tokyo 180-8633, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Yokoyama
authors.affiliation: Department of Material and Life science, Seikei University, 3-3-1, Kichijyoji-kitamachi, Musashino-shi, Tokyo 180-8633, Japan.
authors.forename: Satoka
authors.initials: S
authors.lastname: Aoyagi
authors.affiliation: Department of Physiology 2, Kawasaki Medical School, 577 Matsushima, Kurashiki-shi, Okayama 701-0192, Japan.
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Himi
authors.affiliation: Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, SE-412 96, Sweden.
authors.forename: John S
authors.initials: JS
authors.lastname: Fletcher
authors.affiliation: School of Chemistry, The University of Manchester, Manchester, M13 9PL, UK.
authors.forename: Nicholas P
authors.initials: NP
authors.lastname: Lockyer
authors.affiliation: School of Chemical Engineering and Analytical Science, The University of Manchester, Manchester, M13 9PL, UK.
authors.forename: Alex
authors.initials: A
authors.lastname: Henderson
authors.affiliation: School of Chemical Engineering and Analytical Science, The University of Manchester, Manchester, M13 9PL, UK.
authors.forename: John C
authors.initials: JC
authors.lastname: Vickerman
mesh_terms: D000818:Animals; D001128:Argon; D001923:Brain Chemistry; D002545:Brain Ischemia / Q000473:pathology*; D004195:Disease Models, Animal; D051381:Rats; D018629:Spectrometry, Mass, Secondary Ion / Q000379:methods*
chemical_list: D001128:Argon