title: Storage of cell samples for ToF-SIMS experiments-How to maintain sample integrity.
abstract: In order to obtain comparable and reproducible results from time-of-flight secondary ion mass spectrometry (ToF-SIMS) analysis of biological cells, the influence of sample preparation and storage has to be carefully considered. It has been previously shown that the impact of the chosen preparation routine is crucial. In continuation of this work, the impact of storage needs to be addressed, as besides the fact that degradation will unavoidably take place, the effects of different storage procedures in combination with specific sample preparations remain largely unknown. Therefore, this work examines different wet (buffer, water, and alcohol) and dry (air-dried, freeze-dried, and critical-point-dried) storage procedures on human mesenchymal stem cell cultures. All cell samples were analyzed by ToF-SIMS immediately after preparation and after a storage period of 4 weeks. The obtained spectra were compared by principal component analysis with lipid- and amino acid-related signals known from the literature. In all dry storage procedures, notable degradation effects were observed, especially for lipid-, but also for amino acid-signal intensities. This leads to the conclusion that dried samples are to some extent easier to handle, yet the procedure is not the optimal storage solution. Degradation proceeds faster, which is possibly caused by oxidation reactions and cleaving enzymes that might still be active. Just as well, wet stored samples in alcohol struggle with decreased signal intensities from lipids and amino acids after storage. Compared to that, the wet stored samples in a buffered or pure aqueous environment revealed no degradation effects after 4 weeks. However, this storage bears a higher risk of fungi/bacterial contamination, as sterile conditions are typically not maintained. Thus, regular solution change is recommended for optimized storage conditions. Not directly exposing the samples to air, wet storage seems to minimize oxidation effects, and hence, buffer or water storage with regular renewal of the solution is recommended for short storage periods.
authors.affiliation: Institute of Physical Chemistry, Justus-Liebig-University of Giessen, Heinrich-Buff-Ring 17, 35392 Giessen, Germany.
authors.forename: Kaija
authors.initials: K
authors.lastname: Schaepe
authors.affiliation: Institute of Physical Chemistry, Justus-Liebig-University of Giessen, Heinrich-Buff-Ring 17, 35392 Giessen, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Kokesch-Himmelreich
authors.affiliation: Institute of Physical Chemistry, Justus-Liebig-University of Giessen, Heinrich-Buff-Ring 17, 35392 Giessen, Germany.
authors.forename: Marcus
authors.initials: M
authors.lastname: Rohnke
authors.affiliation: Institute of Veterinary Anatomy, Histology and Embryology, Justus-Liebig-University of Giessen, Frankfurter Strasse 94, 35392 Giessen, Germany.
authors.forename: Alena-Svenja
authors.initials: AS
authors.lastname: Wagner
authors.affiliation: Institute of Veterinary Anatomy, Histology and Embryology, Justus-Liebig-University of Giessen, Frankfurter Strasse 94, 35392 Giessen, Germany.
authors.forename: Thimo
authors.initials: T
authors.lastname: Schaaf
authors.affiliation: Institute of Physical Chemistry, Justus-Liebig-University of Giessen, Heinrich-Buff-Ring 17, 35392 Giessen, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Henss
authors.affiliation: Institute of Veterinary Anatomy, Histology and Embryology, Justus-Liebig-University of Giessen, Frankfurter Strasse 94, 35392 Giessen, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Wenisch
authors.affiliation: Institute of Physical Chemistry, Justus-Liebig-University of Giessen, Heinrich-Buff-Ring 17, 35392 Giessen, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Janek
mesh_terms: D000596:Amino Acids / Q000032:analysis; D002478:Cells, Cultured; D006801:Humans; D008055:Lipids / Q000032:analysis; D059630:Mesenchymal Stem Cells / Q000737:chemistry*; D013048:Specimen Handling / Q000379:methods*; D018629:Spectrometry, Mass, Secondary Ion / Q000379:methods*
chemical_list: D000596:Amino Acids; D008055:Lipids
references.citation: Nature. 2003 Dec 18;426(6968):895-9
references.pmid: 14685250
references.citation: Cytotherapy. 2004;6(1):7-14
references.pmid: 14985162
references.citation: Anal Chem. 2008 Dec 1;80(23):9058-64
references.pmid: 19551933
references.citation: Microsc Res Tech. 2007 Sep;70(9):828-35
references.pmid: 17576131
references.citation: J Lipid Res. 1985 Sep;26(9):1015-35
references.pmid: 3906008
references.citation: Anal Chem. 2013 Nov 19;85(22):10869-77
references.pmid: 24131300
references.citation: Appl Surf Sci. 2008 Dec 15;255(4):1298-1304
references.pmid: 19554199
references.citation: J Lipid Res. 2007 Aug;48(8):1846-56
references.pmid: 17496269
references.citation: Anal Bioanal Chem. 2015 Jun;407(16):4555-65
references.pmid: 25869483
references.citation: Biointerphases. 2012 Dec;7(1-4):49
references.pmid: 22893234
references.citation: J Microsc. 1975 Jul;104(2):107-20
references.pmid: 1104850
references.citation: J Phys Chem C Nanomater Interfaces. 2011 Dec 15;115(49):24247-24255
references.pmid: 22308191
references.citation: Anal Chem. 2002 Apr 15;74(8):1824-35
references.pmid: 11985314
references.citation: Langmuir. 2007 Jan 2;23(1):50-6
references.pmid: 17190484
references.citation: Rapid Commun Mass Spectrom. 2011 Apr 15;25(7):925-32
references.pmid: 21416529
references.citation: Biointerphases. 2013 Dec;8(1):15
references.pmid: 24706128
references.citation: Mol Imaging Biol. 2011 Dec;13(6):1067-76
references.pmid: 21161688
references.citation: Biointerphases. 2015 Mar 19;10(1):019016
references.pmid: 25791294
references.citation: J Am Soc Mass Spectrom. 2008 Aug;19(8):1230-6
references.pmid: 18565760
references.citation: Surf Interface Anal. 2011 Jan;43(1-2):354-357
references.pmid: 22058579
references.citation: Biomaterials. 2007 May;28(15):2412-23
references.pmid: 17335898
references.citation: Anal Bioanal Chem. 2013 Nov;405(27):8769-80
references.pmid: 24026517
references.citation: Anal Chem. 1993 May 15;65(10):1431-8
references.pmid: 8517550
references.citation: Anal Chem. 2009 Sep 1;81(17 ):7197-205
references.pmid: 19639962
references.citation: Transfusion. 1996 Aug;36(8):691-8
references.pmid: 8780663
references.citation: Biointerphases. 2013 Dec;8(1):17
references.pmid: 24706130
references.citation: Anal Chem. 2005 Oct 1;77(19):6190-6
references.pmid: 16194078
references.citation: J Am Soc Mass Spectrom. 2012 Nov;23(11):1931-8
references.pmid: 22930440