Figure 2. Tapping-mode AFM images of enamel crystals after interaction with acetamide-capped PAMAM dendrimers. A solution containing G7 PAMAM dendrimers with an acetamide (-NHC(O)CH3)-capped surface was allowed to flow over the crystals and allowed to remain for 2 min before being wicked off. The sample was dried in a desiccator before being imaged in air. (a) After exposure to 1 µL 7-nM dendrimer solution. (b) After exposure to 5 µL 7-nM dendrimer solution. (c) After sample (b) was rinsed with distilled water (pH 7.4). AFM images show the topographical image (1 µm x 1 µm) on the left, and phase image (1 µm x 1 µm) on the right.