Pico plus 5500 ilm afm

For atomic forced microscopy (AFM) imaging of liposomal samples, 10 µl of the samples were deposited onto freshly cleaved muscovite Ruby mica sheets (ASTM V1 Grade Ruby Mica from MICAFAB) for 15–20 minutes. Mica sheets are basically negatively charged so samples bind strongly on the mica surface. After 15 min, the samples were dried by using a vacuum dryer. Sometimes the samples were gently washed with 0.5 ml Milli-Q water to remove molecules that were not firmly attached to the mica and the samples were dried as mentioned above. Acoustic alternative current mode AFM was performed using a Pico plus 5500 ILM AFM (Agilent Technologies, USA) with a piezoscanner maximum range of 9 µm. Micro fabricated silicon cantilevers of 225 µm in length with a nominal spring force constant of 21–98 N/m were used from Nano sensors, USA. Cantilever oscillation frequency at 150–300 kHz was tuned into resonance frequency. The images (512 by 512 pixels) were captured with a scan size between 0.5 and 2 µm at a scan speed rate of 0.5lines/S. Images were flattened using Pico view1.4 version software (Agilent Technologies). Image processing and analyzation was done through Pico Image Advanced version software (Agilent Technologies).