High-speed and High-resolution AFM

The Atomic Force Microscopy (AFM) station for high-speed video-rate (>1200 lines/sec, fast force mapping 1 kHz) and ultra high-resolution can perform imaging and spectroscopy of the dynamics of biomolecular interactions in physiological environment, integrating correlative fluorescence microscopy and AFM biomechanics.

The instrument is a high resolution atomic force microscope, operating at high speed (“fast-imaging”) in tapping imaging mode (AC mode), producing high quality images. The instrument supports ‘video-rate’ imaging, in AC mode, with a scanning speed of 1250 lines/s. In addition, the machine provides “fast force mapping” option, an imaging mode that allows quantitative maps of the dissipative and non-dissipative modulus of the sample, at high pixel resolution.
The instrument allows morpho-mechanical characterisation with high spatial (< 1nm) and temporal (microseconds) resolution data of biological sample surfaces. The instrument has a true quantitative control of the tip-sample interaction force, enabling the capture of dynamic cellular/subcellular/molecular processes in physiologically relevant environments at very high resolution.

• Image under ambient conditions in air or liquids.
• Conventional imaging mode: scanning speeds of 1-2 lines/s, for high spatial resolution images (atomic resolution of the mica surface, in liquid).
• Fast, stable, high-resolution tapping mode imaging (AC mode).
• Video-rate imaging at up to 1250 lines/s in tapping mode (including phase) and contact mode.
• Sample scanning in the XY and Z directions during imaging. The sample during scanning remains stationary with respect to the AFM frame to allow for future co-locations with other microscopies.
• Fast force mapping mode for quantitate data on mechanical properties of sample, including elastic modulus, hardness, and adhesion at high resolution (1024 x 1024 pixel). The acquisition of fast force mapping is performed in AC imaging mode at conventional scan speeds (1 line/s, < 20 minutes total).
• For normal-rate scanning and video-rate scanning, sample size allowed is up to 15 mm in diameter and 5 mm in height.
• Full digital control of all functions from the AFM workstation via dedicated software.
• Different light sources for measuring cantilever deflection: modulated laser diode source; superluminescent diode source; small spot modulated laser diode source with nominal 3×9 μm spot size for imaging applications with small cantilevers; spot positioning and detector adjustment are fully motorized and software controlled to easily change the light source.
• Different mapping mode are available for normal-rate scanning, fast-scanning, and video-rate: tapping mode; contact mode; bimodal or dual AC AFM; electric force microscopy; Kelvin probe force microscopy; lateral force microscopy; loss tangent imaging mode; magnetic force microscopy; piezoresponse force microscopy.
• Second laser source that drives the cantilever photothermally at its resonance for tapping mode techniques, with drive frequency up to 8 MHz. The resulting response is very stable over time. This preserves tip sharpness, and maintains gentle, high resolution imaging.
• X,Y scanner equipped with closed-loop scanning system, for normal-rate scanning, fast-scanning, and video-rate imaging mode with sensor noise < 60 pm.
• In video rate imaging mode, X, Y maximum scan size varies with line scan rate, scaling from 30 μm for rates <640 Hz to 500 nm for rates >1000 Hz.
• Z range is > 5 μm in normal-rate scanning and >2 μm in video rate scanning.

📍 The “High-speed and high-resolution AFM” is located at the NanoInnovation Laboratory of Elettra Sincrotrone Trieste in Area Science Park.

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