A New Dynamic in Mass Spectral Imaging of Single Biological Cells

Abstract

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) has unique capabilities in the area of high-resolution mass spectrometric imaging of biological samples. The technique offers parallel detection of native and non-native molecules at physiological concentrations with potentially submicrometer spatial resolution. Recent advances in SIMS technology have been focused on generating new ion sources that can in turn be used to eject more intact molecular and biological characteristic species from a sample. The introduction of polyatomic ion beams, particularly C60, for TOF-SIMS analysis has created a whole new application of molecular depth profiling and 3D molecular imaging. However, such analyses, particularly at high lateral resolution, are severely hampered by the accompanying mass spectrometry associated with current TOF-SIMS instruments. Hence, we have developed an instrument that overcomes many of the drawbacks of current TOF-SIMS spectrometers by removing the need to pulse the primary ion beam. The instrument samples the secondary ions using a buncher that feeds into a specially designed time-of-flight analyzer. We have validated this new instrumental concept by analyzing a number of biological samples generating 2D and 3D images showing molecular localization on a subcellular scale, over a practical time frame, while maintaining high mass resolution. We also demonstrate large area mapping and the MS/MS capability of the instrument.

Controlling the Release of Indomethacin from Glass Solutions Layered with a Rate Controlling Membrane Using Fluid-Bed Processing. Part 1: Surface and Cross-Sectional Chemical Analysis

“…ToF-SIMS has been used as a surface analysis technique in a wide array of research fields; from biological samples (cells, tissues, proteins, lipids…) [13][14][15][16][17] , over material science 18 to pharmaceutical formulations [19][20][21][22][23][24] . ToF-SIMS is based upon the bombardment of a sample surface with a primary ion beam (e.g.…”

Single-Cell Analysis: Visualizing Pharmaceutical and Metabolite Uptake in Cells with Label-Free 3D Mass Spectrometry Imaging

“…11,12 The sub-micron lateral resolution and nanometer depth resolution of SIMS opens the possibility for three-dimensional molecular imaging of pharmaceuticals at the single cell level. [13][14][15][16][17] Although, sensitivity and matrix effects have limited the role of SIMS in pharmacology, technological advancements, particularly the advent of cluster ion sources, have improved the technique's sensitivity. 18,19 The advantage of cluster sources is two-fold; as an analysis beam cluster sources improve molecular ion yields and as a sputtering beam, they reduce damage accumulation allowing the molecular ion sensitivity to be maintained throughout the sample.…”

Advanced Optical Imaging of Endocytosis

“…Spectral imaging has been implemented in a variety of optical modalities for biological applications including visible reflectance (Zuzak, et al, 2002), fluorescence (Michalet, et al, 2003) and vibrational spectroscopies such IR absorption (Levin & Bhargava, 2005), Raman scattering (Christensen & Morris, 1998), and surface-enhanced Raman (SERS) (Sharonov, et al, 1994)), as well as in non-optical methods like mass spectrometry (Fletcher, et al, 2008). In practice, higher degrees of multiplexing, higher accuracy, and lower detection limits are achievable with spectral imaging due to the ability to implement multivariate analysis methods to identify and/or classify spectral signatures even in the presence of high degrees of spectral overlap from other labels and cellular autofluorescence (Mansfield, et al, 2005).…”