| AVS 66th International Symposium & Exhibition | |
| Biomaterial Interfaces Division | Tuesday Sessions |
| Session BI+AS-TuM |
| Session: | Characterization of Biological and Biomaterial Surfaces |
| Presenter: | Matthias Lorenz, Oak Ridge National Laboratory |
| Authors: | M. Lorenz, Oak Ridge National Laboratory S.T. King, Oak Ridge National Laboratory N. Borodinov, Oak Ridge National Laboratory C.A. Steed, Oak Ridge National Laboratory J. Chae, Oak Ridge National Laboratory A.V. Ievlev, Oak Ridge National Laboratory O.S. Ovchinnikova, Oak Ridge National Laboratory |
| Correspondent: | Click to Email |
Matrix Assisted Laser Desorption/Ionization (MALDI) is commonly used for the chemical imaging of biological tissue samples with mass spectrometry due to its capability to desorb and ionize large organic molecules with limited fragmentation, thus preserving a high degree of molecular information. MALDI is suitable to analyze species such as peptides and proteins, and the intact molecular ion is observable in many cases.[1] The achievable spatial resolution using MALDI mass spectrometry imaging (MSI) is limited to about 30 µm using standard matrix compounds, primarily due to the dimensions of matrix crystals and the stability of the matrix coating.[2] Time-of-Flight (ToF) Secondary Ion Mass Spectrometry (SIMS) is another mass spectrometry based chemical imaging technique that can achieve a spatial resolution below 100 nm.[3] The chemical information obtained from ToF-SIMS analyses is, however, limited to smaller organic molecules and elemental species due to a more significant fragmentation of intramolecular bonds and decreasing ion yields with increasing molecular weight. We present here a workflow comprising the consecutive application of ToF-SIMS and MALDI-ToF-MS MSI to combine the strength of both chemical imaging techniques. Even though mass spectrometry based surface analysis techniques are inherently destructive in nature, the volumes of sample material that the two imaging techniques extract at each sampling location differs significantly (~30 µm vs. ~100 nm craters). This difference enables the assumption of a non-destructive nature for the ToF-SIMS imaging cycle relative to the MALDI sampling volume and spatial resolution, leaving a virtually pristine sample surface for a subsequent MALDI imaging cycle of the same sample area. We showcase the application of our workflow for the multimodal imaging of a coronal mouse brain tissue section, with automated co-registration of the two imaging data sets. We demonstrate how the MALDI mass spectral data enable to complement the high spatial resolution ToF-SIMS MSI data set with an additional degree of molecular structural information and discuss our workflow based on the visualization of signaling molecules in the mouse brain tissue.
[1] Todd, P.J.; Schaaff, T.G.; Chaurand, P.; Caprioli, R.M. J. Mass Spectrom. 2001, 36, 355−369.
[2] Yang, J.; Norris, J.L.; Caprioli, R. J. Mass Spectrom. 2018, 53, 1005−1012.
[3] Kollmer, F.; Paul, W.; Krehl, M.; Niehuis, E. Surf. Interface Anal. 2013, 45, 312−314.