| Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2018) | |
| Biomaterial Surfaces & Interfaces | Monday Sessions |
| Session BI-MoM |
| Session: | 35 Years of NESAC/BIO I |
| Presenter: | Michael Taylor, University of Washington |
| Authors: | M.J. Taylor, University of Washington D.J. Graham, University of Washington L.J. Gamble, University of Washington |
| Correspondent: | Click to Email |
ToF-SIMS is uniquely suited towards high spatial resolution imaging of surface modifications in materials with structure. While imaging 2D “flat” surfaces is relatively simple, working with three-dimensional (3D) “rough” surfaces is challenging due to the topography. This topography interferes with the ability to extract spatio-chemical differences in the sample and results in image shadowing and decreased mass resolution. In 3D depth profiling, topography can cause differential etching as the sputtering beam can impact the surface at different heights and angles. In many cases the combination of these factors prevents acquiring high quality imaging data since features associated with surface chemistry can be obscured. Multivariate image analysis methods have been used to assess the impact of topography on ToF-SIMS data, and AFM has been applied for topographical correction. However, the former method only assesses the impact, while the latter is time consuming and does not mitigate the effects of surface topography entirely. We propose an alternate methodology for imaging topographic samples with ToF-SIMS, demonstrating that through a simple polymer embedding methodology, topographic materials, ill-suited for ToF-SIMS analysis can be transformed into surfaces where topographical effects are minimized and high spatial resolution label free imaging of chemical modifications can be performed in topographic materials1. Imaging surface modifications in the pores of biopolymer scaffolds will be presented, using a highly focused Bi3+ LMIG beam for analysis in 2D, and the addition of an Ar1500+ sputter beam for depth profiling the pore in 3D.
FC (fluorocarbon) modification of PCL pores will be imaged, showing FC film deposits in the scaffold pore, and its distribution can be imaged in 3D. Water plasma hydrolyzed PCL scaffolds, modified with bovine serum albumin (BSA) through EDC/NHS bioconjugation chemistry can similarly be imaged, unlocking label free imaging of protein fragments at the scaffold/pore interface. We will also show that lipid imaging is possible in this challenging material class, extracting information in 2 and 3D from the pores of lipid modified poly(2-hydroxyethyl methacrylate)-co-methacrylic acid scaffolds.
1 M. J. Taylor, H. Aitchison, M. J. Hawker, M. N. Mann, E. R. Fisher, D. J. Graham and L. J. Gamble, Biointerphases, 2018, 13, 03B415.