Wednesday, March 19, 2014

Tapping AFM: Arabidopsis haliana Grana Membranes

Images of Arabidopsis thaliana grana membranes using tapping AFM. 

The Dimension 3000 AFM was used to image these membranes in air with stiff silicon probes (Olympus #OMCLAC160TS-W2, with 7 nm tip radius and 42 N/m spring constant). Arabidopsis thaliana grana membranes were isolated through treatment with 2% digitonin showing semi-crystalline array formation of photo-system II complex proteins due to changes in growth light intensity. Protrusions are the water splitting complex of photo-system II in photosynthetic membranes. Scale bar is 375 nm. 
 
Thanks to Stefanie Tietz and Dr. Helmutt Kirchoff, Washington State University Molecular Plant Sciences, as well as Dr. Steve Lenhert, FSU Department of Biology.

Monday, March 17, 2014

Lipid Grating

This image shows a dipalmitoyl phosphatidylcholine (DPPC) multilayer grating fabricated by lipid multilayer stamping. The image was taken in air using tapping mode, and is a good example of soft materials imaged in air using AFM techniques.

O. A. Nafday, T. W. Lowry, S. Lenhert, Multifunctional lipid multilayer stamping, Small 8, 1021-1028 (2012).