RESUMO
Utilizing atomic force microscope (AFM) with a diamond tip, we were able to successfully plough nano-constrictions on epitaxially grown YBa2Cu3O(7-x) thin films deposited on MgO substrates. The thickness, width, and length of the obtained constrictions were in the range of a few 100 nm. Furthermore, we managed to produce a new S-type constriction, of which the dimensions are easier to control than for conventional constrictions.
Assuntos
Óxido de Magnésio/química , Microscopia de Força Atômica/métodos , Nanotecnologia/métodos , Alumínio/química , Bário/química , Cobre/química , Cristalização , Diamante , Eletroquímica , Teste de Materiais , Nanopartículas Metálicas/química , Nanopartículas/química , Propriedades de Superfície , Ítrio/químicaRESUMO
The influences of the antibacterial magainin 2 and PGLa from the African clawed frog (Xenopus laevis) and the hemolytic bee venom melittin on Escherichia coli as the target cell were studied by atomic force microscopy (AFM). Nanometer-scale images of the effects of the peptides on this gram-negative bacterium's cell envelope were obtained in situ without the use of fixing agents. These high-resolution AFM images of the surviving and intact target cells before and after peptide treatment showed distinct changes in cell envelope morphology as a consequence of peptide action. Although all three peptides are lytic to E. coli, it is clear from this AFM study that each peptide causes distinct morphological changes in the outer membrane and in some cases the inner membrane, probably as a consequence of different mechanisms of action.