Chapter 14. Nanoscale electromagnetic measurements for life science applications
Thomas M. Wallis, Pavel Kabos
Historically, the most prominent techniques for biomaterial imaging have been optical techniques, especially those based on fluorescence imaging. Many of these techniques require staining of the bio-materials to induce contrast. Such techniques for inducing contrast in optical images date back to the nineteenth century and played a central role in biological imaging of that period, such as the work of 1906 Nobel Prize winner Santiago Ramon y Cajal. Fig. 14.1 shows the dimensions of relevant biological specimens. Depending on the length scale of interest, a variety of different microscopy techniques are available. For comparison, Fig. 14.1 also illustrates comparable solid state, electronic systems at various length scales. In this chapter, we will describe methods for imaging and characterization of biological materials at sub-micrometer length scales. The focus will be on electrical scanning probe imaging methods, but by way of introduction we will discuss selected optical methods. The number of applications of scanning probe microscopy to biological systems is large. Many widely-used applications, such as the application of atomic force microscopes (AFMs) to mechanical characterization of the proteins and cells, are beyond the scope of this chapter.