Biological applications of atomic force microscopy

Principal Investigator: György Váró


Oligonucleotides and peptides

Reaction centers and nanotubes

Living cerebral endothelial cells

Molecular motion of bacteriorhodopsin

The investigation of the interaction between bacterial photosynthetic reaction centers (RCs) and single walled carbon nanotubes (SWNTs) opens the possibility of different practical applications in microelectronics or in energy conversion. The RC is a pigment protein complex in which light energy initiates a chain of intraprotein electron transport reactions. Carbon nanotubes are efficient in biomatter-based devices. The working hypothesis was that the SWNTs could play the role of electrodes by evacuating the photoexcited electrons from the RCs.

The SWNTs showed 1 nm high fibrous-like structures and dried on the mica surface, they assembled in bundles of 3 5 pieces. The surface-dried RCs presented small, uniformly spread spots with an average height of 9 ± 1 nm. The mixture of RCs and SWNTs presented carbon nanotubes coated with proteins. From the height profile it could be derived that the RCs were sitting on the nanotubes forming a complex with an average height of 15 ± 2 nm.

Single walled carbon nanotube covered with reaction centers. 1 x 1 µm2 AC mode error signal image.

Dorogi M., Z. Bálint, C. Mikó, B. Vileno, M. Milas, K. Hernádi, L. Forró, G. Váró and L. Nagy. 2006. Stabilization effect of single walled carbon nanotubes on the functioning of photosynthetic reaction centers. Journal of Physical Chemistry B. 110 (43):21473-21479.