Per Malmberg oral presentation (PB2-Mon4-1-1)
Graphene as a matrix for improved imaging mass spectrometry of biological tissue
1 Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivägen 10, 41296 Gothenburg, Sweden
2 Medicinal Chemistry, Respiratory, Inflammation & Autoimmunity, Innovative Medicines and Early Development Biotech Unit, AstraZeneca, Pepparedsleden 1, 43183 Mölndal, Sweden
3 Department of Microtechnology and Nanoscience, Electronics Materials and Systems Laboratory, Chalmers University of Technology, Kemivägen 9, 41296 Gothenburg, Sweden
Graphene as a matrix has shown promising effects on imaging mass spectrometry since it is a high conductive substance with a good heat transferring ability . Graphene is a substance solely built up by carbon atoms that breaks down into smaller carbon ion fragments when ionized, hence produces less fragments compared to conventional matrices .
Graphene and graphene oxide have been used as matrices for MALDI with promising results . However, for SIMS, graphene oxide has until now only been used as a matrix for analyte solutions . In this study, we present and evaluate how graphene and graphene oxide can be used a as matrices on tissues for ToF-SIMS analysis.
An IONTOF TOF SIMS 5 was used to analyse rat kidney tissue, with and without applied graphene matrices using Bi3++ ions. Solutions of graphene and graphene oxide were prepared using Hummers method . The graphene solution was applied using spin-coating and the graphene oxide solution was applied with an HTX-sprayer. The application of matrices was studied using scanning electron microscopy (SEM). Statistical analyses were made with Analysis of Variance (ANOVA), Least Significant difference (LSD) and Principal Component Analysis (PCA). These analyses showed that there is a significant difference between the matrices and their effects on the sample.
Graphene and especially graphene oxide increased the intensity of peaks in the higher interval of the mass spectrum, around 500-1200 Da. Some of the peaks that were discovered with the usage of graphene oxide as a matrix, were not detectable without a matrix. However, the intensity did not increase for all peaks and graphene and graphene oxide affected different peaks in different ways.
For efficient use of the matrices, optimization of the production and application is necessary and further studies are needed to fully evaluate the effect of graphene as a matrix for ToF-SIMS. Yet using graphene and graphene oxide as matrices in SIMS shows great promise in enhancing tissue imaging of selected compounds and allows an easy approach to multimodal imaging with ToF-SIMS and MALDI.
 C. N. R. Rao, A. K. Sood, K. S. Subrahmanyam, and A. Govindaraj, Angewandte Chemie - International Edition 48(42), 2009, pp. 7752–7777.
 A. Bodzon-Kulakowska and P. Suder, Mass Spectrometry Reviews 35(1), 2016, pp. 147–169.
 W. L. Friesen, B. J. Schultz, J. F. Destino, T. E. G. Alivio, J. R. Steet, S. Banerjee,
and T. D. Wood, Journal of the American Society for Mass Spectrometry 26(11), 2015, pp. 1963–1966.
 L. Cai, L. Sheng, M. Xia, Z. Li, S. Zhang, X. Zhang, and H. Chen, Journal of The American Society for Mass Spectrometry, 2016.
 W. S. Hummers and R. E. Offeman, Journal of the American Chemical Society 80(6), 1958, pp. 1339.