| AVS 56th International Symposium & Exhibition | |
| Biomaterial Interfaces | Tuesday Sessions |
| Session BI-TuM |
| Session: | Proteins and Cell Interactions at Interfaces II |
| Presenter: | B.O. Leung, McMaster University, Canada |
| Authors: | B.O. Leung, McMaster University, Canada A.P. Hitchcock, McMaster University, Canada J.L. Brash, McMaster University, Canada A. Scholl, Advanced Light Source A. Doran, Advanced Light Source |
| Correspondent: | Click to Email |
Upon implantation in biological tissue or first contact with blood, all materials are immediately coated with a layer of proteins. The details of this initial protein layer can have a very strong effect on biocompatibility [1]. Thus, characterization of the surfaces of biomaterials and their interaction with relevant proteins can help to determine and understand biocompatibility.
We use synchrotron based X-ray photoemission electron microscopy (X-PEEM) [2] and scanning transmission X-ray microscopy (STXM) [3] to study the spatial distribution of adsorbed proteins on chemically heterogeneous surfaces. Both techniques have a lateral spatial resolution below 40 nm, provide speciation and quantitation through spatially resolved near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, and can be used to obtain quantitative maps of the adsorbed protein in relation to the topography and chemistry of the underlying substrate with high sensitivity [4-5]. X-PEEM probes the top 10 nm of the sample whereas STXM integrates over the full sample thickness (40-100 nm) and can be applied to fully hydrated samples.
Results from three recent studies will be presented. (1) spun-cast thin films of phase-segregated polystyrene blended with cross-linked polyethylene oxide (PEO ) adsorb human serum albumin (HSA) more readily to the PEO -rich areas compared to plasma-deposited diglyme surfaces, which are known protein resistant materials. Due to incomplete phase segregation, PEO imparts some protein resistance to the PS region. (2) HSA adsorption to polystyrene/ poly(methyl methacrylate)-b-polyacrylic acid (PS/PMMA-b-PAA ) thin films show strong modifications of the adsorption behavior relative to HSA adsorption to PS/PMMA surfaces due to strong and specific electrostatic interactions between the positively charged peptide and the negatively charged PMMA-b-PAA domains. (3) Protein adsorption to PS-PMMA spun-cast films has been examined by STXM in a fully hydrated wet cell. In the presence of water, HSA preferentially adsorbs to the discrete polar PMMA domains rather than the continuous PS domain, whereas the latter is favored under dried conditions [2]. [6]
1. D. G. Castner, and B. D. Ratner, Surface Science 2002, 500, 28 – 60.
2. L.Li, J. Brash, R. Cornelius and A. P. Hitchcock J. Phys. Chem B 2008, 112, 2150-58
3. H. Ade and A.P. Hitchcock, Polymer 2008, 49, 643-675.
4. B. O. Leung, A. P. Hitchcock et al. Macromolecules 2009, 42, 1679 – 1684.
5. B. O. Leung, A. P. Hitchcock et al. Biomacromolecules 2009, in press
6. Research carried out with PEEM2 and STXM532 at the Advanced Light Source, which is supported by Basic Energy Sciences, DoE, USA. Research funded by NSERC.