Imaging of membrane lipids in single cells by imprint-imaging time-of-flight secondary ion mass spectrometry.
A new method for identification and localization of organic molecules in biological samples is described. The method involves making an imprint of a biological sample on a silver (Ag) surface and subsequent analysis of the imprint by imaging time-of-flight secondary ion mass spectrometry (TOF-SIMS). Using this method, detection of unfragmented, Ag cationized molecules at a spatial resolution of <0.5 microm is possible. We have used the method to study the spatial distribution of phosphatidylcholine and cholesterol in blood cells adhering to a glass surface. The TOF-SIMS images show that cholesterol is preferentially located in the plasma membrane, whereas the phosphocholine shows highest concentration in the nuclear membrane. Scanning electron microscopy and fluorescence microscopy images show that the amount of transferred material during the imprinting process can be controlled by varying the imprinting pressure and pretreatment of the cell substrate prior to imprinting.
Chemistry and Materials Technology, SP Swedish National Testing and Research Institute, P.O. Box 857, SE-501 15 Borås, Sweden. peter.sjovall@sp.se
Peter
P
Sjövall
Jukka
J
Lausmaa
Håkan
H
Nygren
Lennart
L
Carlsson
Per
P
Malmberg
D002477:Cells / Q000737:chemistry; D003952:Diagnostic Imaging; D006801:Humans; D013058:Mass Spectrometry; D008563:Membrane Lipids / Q000737:chemistry*; D008566:Membranes / Q000737:chemistry / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning
D008563:Membrane Lipids