title: Chromosome observation by scanning electron microscopy using ionic liquid.
abstract: Electron microscopy has been used to visualize chromosome since it has high resolution and magnification. However, biological samples need to be dehydrated and coated with metal or carbon before observation. Ionic liquid is a class of ionic solvent that possesses advantageous properties of current interest in a variety of interdisciplinary areas of science. By using ionic liquid, biological samples need not be dehydrated or metal-coated, because ionic liquid behaves as the electronically conducting material for electron microscopy. The authors have investigated chromosome using ionic liquid in conjunction with electron microscopy and evaluated the factors that affect chromosome visualization. Experimental conditions used in the previous studies were further optimized. As a result, prewarmed, well-mixed, and low concentration (0.5∼1.0%) ionic liquid provides well-contrasted images, especially when the more hydrophilic and the higher purity ionic liquid is used. Image contrast and resolution are enhanced by the combination of ionic liquid and platinum blue staining, the use of an indium tin oxide membrane, osmium tetroxide-coated coverslip, or aluminum foil as substrate, and the adjustment of electron acceleration voltage. The authors conclude that the ionic-liquid method is useful for the visualization of chromosome by scanning electron microscopy without dehydration or metal coating.
authors.affiliation: Laboratory of Dynamic Cell Biology, Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, Osaka, Japan.
authors.forename: Astari
authors.initials: A
authors.lastname: Dwiranti
authors.forename: Linyen
authors.initials: L
authors.lastname: Lin
authors.forename: Eiko
authors.initials: E
authors.lastname: Mochizuki
authors.forename: Susumu
authors.initials: S
authors.lastname: Kuwabata
authors.forename: Akio
authors.initials: A
authors.lastname: Takaoka
authors.forename: Susumu
authors.initials: S
authors.lastname: Uchiyama
authors.forename: Kiichi
authors.initials: K
authors.lastname: Fukui
mesh_terms: D000818:Animals; D022004:Chromosome Structures / Q000648:ultrastructure; D002877:Chromosomes, Human / Q000235:genetics / Q000648:ultrastructure*; D006367:HeLa Cells; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D052578:Ionic Liquids / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D018668:Muntjacs / Q000033:anatomy & histology / Q000235:genetics*; D011073:Polyamines / Q000378:metabolism; D013194:Staining and Labeling; D014618:Vacuum
chemical_list: D052578:Ionic Liquids; D011073:Polyamines