Emanuele Salvietti

Trace Copper(II) or Zinc(II) Ions Drastically Modify the Aggregation Behavior of Amyloid-beta(1-42): An AFM Study

Formation of amyloid-beta (Abeta){1-42} amyloid fibrils, a characteristic feature of Alzheimers disease (AD), was monitored in situ through atomic force microscopy (AFM). Well-structured amyloid fibrils slowly formed in solution within 24 hours for which high quality AFM pictures could be obtained. Remarkably, addition of either copper(II) or zinc(II) ions to the incubation medium, even at extremely low molar ratios, dramatically changed the Abeta {1-42} aggregation profile and prevented fibril formation. Aggregates of different morphology appeared in accordance with previous observations: small globular aggregates upon addition of zinc; ill-structured micro-aggregates in the case of copper. The implications of these AFM results are discussed in the context of current concepts for AD metallobiology.

Investigations on the Electrochemical Atomic Layer Growth of Bi2Se3 and the Surface Limited Deposition of Bismuth at the Silver Electrode

The Electrochemical Atomic Layer Deposition (E-ALD) technique is used for the deposition of ultrathin films of bismuth (Bi) compounds. Exploiting the E-ALD, it was possible to obtain highly controlled nanostructured depositions as needed, for the application of these materials for novel electronics (topological insulators), thermoelectrics and opto-electronics applications. Electrochemical studies have been conducted to determine the Underpotential Deposition (UPD) of Bi on selenium (Se) to obtain the Bi2Se3 compound on the Ag (111) electrode. Verifying the composition with X-ray Photoelectron Spectroscopy (XPS) showed that, after the first monolayer, the deposition of Se stopped. Thicker deposits were synthesized exploiting a time-controlled deposition of massive Se. We then investigated the optimal conditions to deposit a single monolayer of metallic Bi directly on the Ag.