Major advances have been made in biomedical surface analysis since the National ESCA and Surface Analysis Center for Biomedical Problems (NESAC/Bio) was founded by Buddy Ratner in 1983. Initially, most of the biomedical surface analysis studies were single technique analysis of homogeneous surfaces, but now most biomedical surface analysis studies use a complementary, multitechnique approach for obtaining detailed, comprehensive information about a wide range of surfaces and interfaces of interest to the biomedical community. Significant advances have been made in widely used surface analysis techniques such as x-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) (e.g., new mass analyzers and primary ion sources for ToF-SIMS). In addition, new advanced surface analysis techniques such as sum frequency generation vibrational spectroscopy, as well as advanced data analysis methods such as multivariate analysis, have been introduced. Another area of development has been the preparation and handling of biological samples for surface analysis, especially for techniques such as XPS and ToF-SIMS where the analysis is done under ultrahigh vacuum conditions. The driving force for all these advances has been that the surface of a biomaterial is the interface between the biological environment and the biomaterial, so the development of state-of-the-art instrumentation, experimental protocols, and data analysis methods is needed to provide a detailed surface structure and composition information about biomedical devices that can be related to the biological performance of these biomedical devices. To maximize the impact of biomedical surface analysis, it needs to be integrated with novel materials synthesis strategies and detailed biological studies, thereby providing us with a better understanding of how surface properties of a biomaterial affect its biological performance and allowing biomedical researchers to design devices with improved and novel biological properties. For a more extensive review of the advances made in biomedical surface analysis, the reader is referred to D. G. Castner, Biointerphases 12 (2017), paper 02C301.
Some focus areas for biomedical analysis include characterization of immobilized biomolecules, surface functionalization, complex biomedical surfaces, cell-surface interactions, and nanoparticles, as well as 2D/3D imaging of biological materials. The articles in this special issue provide excellent examples of the breath of current biomedical surface analysis techniques being used and topics being studied. All the NESAC/Bio students, post-doctoral fellows, staff, investigators, and collaborators, as well as all biomedical surface analysts around the world, are thanked for the important and significant contributions they have made to the advancement and development of biomedical surface analysis.
