Etched silicon cantilevers

AFM images were acquired in the tapping mode using a Nanoscope IIId scanning probe microscope with Extender Module (Bruker, Billerica, MA, USA) in the dynamic modus. An active vibration isolation platform was applied. Olympus etched silicon cantilevers were used with a typical resonance frequency in the range of 200–400 kHz and a spring constant of 42 N/m. The set-point amplitude of the cantilever was maintained by the feedback circuitry to 80% of the free oscillation amplitude of the cantilever. All samples were measured at room temperature in air. The sample was first adjusted with an optical light microscope (Nanoscope, Optical Viewing System).
For this study, mica plates (Nanowords) were coated by undoped and Photolon doped sol–gel matrices, as well as undoped and Protoporphyrin IX (PPIX) doped sol–gel layers. The distribution of PS molecules on the coating surface was analyzed.

AFM is an appropriate method for the characterization of pre-fibrillar protein assemblies. Here, 5 μl of a 40 μM Aβ peptide solution were applied on a 0.5 mm² freshly cleaved sheet of mica for 10–30 seconds and then removed by fast spinning off. AFM images were recorded using a MultiMode scanning probe microscope (either NanoScope IIIa, Digital Instruments Inc., or NanoScope IV, Veeco Instruments Inc., Santa Barbara, California, USA), equipped with a 10 μm scanner (E-scanner). Height and phase images were recorded in tapping mode with scan rates of 2–4 lines per second and a resolution of 512 × 512 pixels. Olympus etched silicon cantilevers were used with a typical resonance frequency in the range of 60–80 kHz and a spring constant of 2 N/m. All samples were investigated on dry substrates of mica (PLANO W. Plannet GmbH, Wetzlar, Germany) at room temperature open to air.