Interaction between carbon nanotubes and bacterial photosynthetic reaction centers

György Váró *, Zoltán Bálint *, Márta Dorogi #, Klára Hernádi + and László Nagy #

* Institute of Biophysics, Biological Research Center, Szeged, Hungary; # Department of Biophysics, University of Szeged, Hungary; + Department of Applied and Environmental Chemistry, University of Szeged, Hungary

Suspension of photosynthetic reaction center of Rhodobacter sphaeroides was mixed with both, single wall and multiple wall carbon nanotubes. Dried samples were prepared from these mixtures on microscope glass slide for absorption kinetic measurements, or on freshly cleaved mica surface for atomic force microscope (AFM) study. The AFM images demonstrate that the reaction centers coated the surface of the carbon nanotubes, perhaps in an oriented way. While the dried sample, prepared from reaction centers only, showed one characteristic orientation of the protein on the mica surface, the nanotube containing samples exhibited other structure. From the thickness profile the dimension of the coated and uncoated tubes could be determined. The photoexcitation of the dried samples containing reaction centers with or without carbon nanotubes produced characteristically different absorption kinetic signals. The samples containing photosynthetic reaction centers with carbon nanotubes showed a markedly long lasting stability.

Email: varo@nucleus.szbk.u-szeged.hu

Address: Dr. György Váró, Biological Research Center, 6726 Szeged,, Temesvári krt. 62, Hungary