Left: Height image of network of nanostructured calcium phosphate particles (white areas)
interconnected by DNA (interconnecting lines), 20µm scan.
Right: Phase image showing lighter regions where there is a greater attraction
between the tip and sample. In contrast, the DNA strands appear darker
indicating a more
repulsive interaction between the tip and sample, 20µm scan.
Sample courtesy of P. Kumta, Carnegie Mellon University.