Bioimaging TOF-SIMS: High Resolution 3D Imaging of Single Cells

KEY WORDS imaging MS; TOF-SIMS; 3D imaging; thyroid tumor cells; cell membrane; phospholipids; potassium compartment ABSTRACT The distribution of phosphocholine ions (m/z 184, m/z 86), sodium ions, and po-tassium ions in thyroid tumor cells was analyzed by imaging TOF-SIMS. Repeated sputtering with a C60 1 source and subsequent analysis with a Bi3 1 gun produced a series of 138 images that were stacked to make a 3D display of the chemistry of cells. Phosphocholine was seen in the plasma membrane (m/z 184) and intracellular membranes (m/z 86). The different fragmentation of the phospholipid probably reflects the chemical composition of membranes at these sites. High inten-sity of secondary ion signals of potassium was seen in membrane-encompassed cellular compart-ments. The data indicate that potassium ions are compartmentalized in thyroid tumor cells