ASTM_E_1880_-_12.pdf

Designation:E188012Standard Practice forTissue Cryosection Analysis with SIMS1This standard is issued under the fixed designation E1880;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice provides the Secondary Ion Mass Spec-trometry(SIMS)analyst with a method for analyzing tissuecryosections in the imaging mode of the instrument.Thispractice is suitable for frozen-freeze-dried and frozen-hydratedcryosection analysis.1.2 This practice does not describe methods for optimalfreezing of the specimen for immobilizing diffusible chemicalspecies in their native intracellular sites.1.3 This practice does not describe methods for obtainingcryosections from a frozen specimen.1.4 This practice is not suitable for any plastic embeddedtissues.1.5 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E673 Terminology Relating to Surface Analysis(Withdrawn2012)33.Terminology3.1 Definitions:3.1.1 See Terminology E673 for definitions of terms used inSIMS.4.Summary of Practice4.1 This practice describes a method for the analysis oftissue cryosections with SIMS.Tissue cryosections for SIMSanalysis need to be mounted flat on an electrically conductingsubstrate.Cryosections should remain flat and adhere well tothe substrate for SIMS analysis.This is achieved by pressingfrozen cryosections into an indium substrate.Indium,being amalleable metal(Moh hardness=1.2,Youngs modulus=10.6GPa),provides a“cushion”for pressing and holding the frozencryosections flat for SIMS analysis.Indium substrates areprepared by pressing sheet indium onto a polished siliconwafer.An approximately 1 m thick layer of indium(99.999%purity)is then vapor deposited on this surface.This top layerprovides“fluffy”indium that helps in holding cryosections flatfor SIMS analysis.5.Significance and Use5.1 Pressing cryosections flat onto a conducting substratehas been one of the most challenging problems in SIMSanalysis of cryogenically prepared tissue specimens.Frozencryosections often curl or peel off,or both,from the substrateduring freeze-drying.The curling of cryosections results in anuneven sample surface for SIMS analysis.Furthermore,iffreeze-dried cryosections are not attached tightly to thesubstrate,the impact of the primary ion beam may result infurther curling and even dislodging of the cryosection from thesubstrate.These problems render SIMS analysis difficult,frustrating and time consuming.The use of indium as asubstrate for pressing cryosections flat has provided a practicalapproach for analyzing cryogenically prepared tissue speci-mens(1).45.2 The procedure described herein has been successfullyused for SIMS imaging of calcium and magnesium transportand localization of anticancer drugs in animal models(2,3,4,5).5.3 The procedure described here is amenable to soft tissuesof both animal and plant origin.6.Apparatus6.1 The procedure described here can be used for tissuecryosection analysis with virtually any SIMS instrument.6.2 A cold stage in the SIMS instrument is needed toanalyze frozen-hydrated specimens(6).1This practice is under the jurisdiction of ASTM Committee E42 on SurfaceAnalysis and is the direct responsibility of Subcommittee E42.06 on SIMS.Current edition approved Nov.1,2012.Published December 2012.Originallyapproved in 1997.Last previous edition approved in 2006 as E1880 06.DOI:10.1520/E1880-12.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4The boldface numbers in parentheses refer to a list of references at the end ofthis standard.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 7.Procedure7.1 Prepare the indium substrate by pressing sheet indiumonto polished silicon wafer pieces of approximately 15 to 25mm2surface area,which can be irregularly shaped.A simplemechanical Pellet Press5can be used effectively for pressingfor pressing sheet indium onto the surface of polished siliconwafer.Next,vapor deposit an approximately 1 m thick layerof high purity(99.999%)indium onto the pressed indiumsheet.The high purity of indium is emphasized only due to thefact that it should not impart any significant contamination tothe sample.The vapor deposition can be achieved by vacuum-based processes such as ev