Atomic Force Microscopy of Cancer Cells

The fixed histological tissues were imaged by Innova AFM (www.bruker.com) operating in tapping mode with phosphorus (n)-doped silicon cantilever (RTESPA, Bruker, Madison, 120 WI, USA) with a nominal tip diameter of 8–10 nm, and nominal spring constant of 40 N/m at 300 kHz resonance frequency. Surface image quality was optimized by lowering the scan rate at 0.2 Hz. All images were acquired with 50 × 50 μm² scan sizes, 512 × 512 data point resolution, and with a pixel size of 97.65 nm. Each scanned sample contains a few CRCs since 11 μm is their median size [47 (link)]. The AFM was installed on a vibration isolation table (minus k technology BM-10) to compensate for regular environmental vibrations and placed inside an acoustic enclosure (Ambios technologies Isochamber) for isolation from thermal and building vibrations and 30 dB acoustic drift. The AFM imaging was performed in air at ambient temperature. In addition to height, the amplitude and phase images were also recorded.