Sweers et al. Nanoscale Research Letters 2011, 6:270 http://www.nanoscalereslett.com/content/6/1/270 Page 5 of 10 Figure 4 Peakforce QNM images in liquid and ambient conditions. Height (A, C) and corresponding elasticity maps (B, D) recorded with Peakforce QNM. Panels A and B are recorded in liquid (setpoint is 14 nN) and C and D in ambient conditions (setpoint is 16 nN). The fibrils have in these images an average modulus of elasticity of 3 GPa and mica between 6 and 7 GPa. Image size is 2 × 2 μm. Figure 5 Peakforce QNM images. Height and stiffness map of fibrils obtained with a setpoint of 1 nN in liquid, images size is 1 μm (A, B). C and D represent the cross-section of the fibril. Notice that in Peakforce QNM the artifacts at the edges of the fibrils seen in HarmoniX (Figure 3F) caused by changing contact areas are absent.