title: Imaging of biomaterials in liquids: a comparison between conventional and Q-controlled amplitude modulation ('tapping mode') atomic force microscopy.
abstract: Lambda phage DNA and DPPC thin films are imaged in liquids by atomic force microscopy applying the amplitude modulation mode ('tapping mode') with active enhancement of the Q-factor by a 'Q-control' electronics. The topography of the resulting images is compared with images obtained without active Q-control. To enable a meaningful comparison, individual scan lines are alternately recorded with and without Q-factor enhancement using scan parameters optimized for each mode separately. As the major finding, significant height differences of topographical features are observed between the two modes. The heights measured with active Q-control are reproducibly higher compared to the ones observed without Q enhancement. This effect is attributed to the reduction of tip-sample forces by Q-control.
authors: Center for Nanotechnology (CeNTech), Gievenbecker Weg 11, 48149 Münster, Germany. Physikalisches Institut, Westfälische Wilhelms Universität Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany.
authors: D
authors: D
authors: Ebeling
authors: H
authors: H
authors: Hölscher
authors: H
authors: H
authors: Fuchs
authors: B
authors: B
authors: Anczykowski
authors: U D
authors: UD
authors: Schwarz