In situ AFM visualization of Li-O battery discharge products during redox cycling in an atmospherically controlled sample cell.

The in situ observation of electrochemical reactions is challenging due to a constantly changing electrode surface under highly sensitive conditions. This study reports the development of an in situ atomic force microscopy (AFM) technique for electrochemical systems, including the design, fabrication, and successful performance of a sealed AFM cell operating in a controlled atmosphere. Documentation of reversible physical processes on the cathode surface was performed on the example of a highly reactive lithium-oxygen battery system at different water concentrations in the solvent.

Zinc-Induced Conformational Transitions in Human Islet Amyloid Polypeptide and Their Role in the Inhibition of Amyloidosis.

Type-2 diabetes mellitus (T2DM) is a disease hallmarked by improper homeostasis within the islets of Langerhans of the pancreas. The most critical species affected is insulin, which is produced by the β-cells of the islets, but there are a number of other species copackaged and cosecreted within the insulin granules. This includes zinc, which exists in high (millimolar) concentrations within the β-cells, and islet amyloid polypeptide (IAPP), which is an amyloid peptide thought to induce β-cell apoptosis through self-association into toxic amyloid oligomers.

Hetero-oligomeric Amyloid Assembly and Mechanism: Prion Fragment PrP(106-126) Catalyzes the Islet Amyloid Polypeptide β-Hairpin.

Protein aggregation is typically attributed to the association of homologous amino acid sequences between monomers of the same protein. Coaggregation of heterogeneous peptide species can occur, however, and is implicated in the proliferation of seemingly unrelated protein diseases in the body. The prion protein fragment (PrP) and human islet amyloid polypeptide (hIAPP) serve as an interesting model of nonhomologous protein assembly as they coaggregate, despite a lack of sequence homology.

Inhibiting and Remodeling Toxic Amyloid-Beta Oligomer Formation Using a Computationally Designed Drug Molecule That Targets Alzheimer's Disease.

Alzheimer's disease (AD) is rapidly reaching epidemic status among a burgeoning aging population. Much evidence suggests the toxicity of this amyloid disease is most influenced by the formation of soluble oligomeric forms of amyloid β-protein, particularly the 42-residue alloform (Aβ42). Developing potential therapeutics in a directed, streamlined approach to treating this disease is necessary.

Human Islet Amyloid Polypeptide Assembly: The Key Role of the 8-20 Fragment.

The aggregation of human islet amyloid polypeptide (hIAPP) has been closely associated with the pathogeny of type 2 diabetes mellitus (T2DM) and destruction of pancreatic islet β-cells. Several amyloidogenic domains within the hIAPP sequence capable of self-association have been identified. Among them is the 8-20 region of hIAPP, which has formed β-sheet fibrils despite being contained within an α-helical region of full-length hIAPP.

Human Islet Amyloid Polypeptide N-Terminus Fragment Self-Assembly: Effect of Conserved Disulfide Bond on Aggregation Propensity.

Amyloid formation by human islet amyloid polypeptide (hIAPP) has long been implicated in the pathogeny of type 2 diabetes mellitus (T2DM) and failure of islet transplants, but the mechanism of IAPP self-assembly is still unclear. Numerous fragments of hIAPP are capable of self-association into oligomeric aggregates, both amyloid and non-amyloid in structure. The N-terminal region of IAPP contains a conserved disulfide bond between cysteines at position 2 and 7, which is important to hIAPP's in vivo function and may play a role in in vitro aggregation.

Amyloid β-Protein Assembly and Alzheimer's Disease: Dodecamers of Aβ42, but Not of Aβ40, Seed Fibril Formation.

Evidence suggests that oligomers of the 42-residue form of the amyloid β-protein (Aβ), Aβ42, play a critical role in the etiology of Alzheimer's disease (AD). Here we use high resolution atomic force microscopy to directly image populations of small oligomers of Aβ42 that occur at the earliest stages of aggregation. We observe features that can be attributed to a monomer and to relatively small oligomers, including dimers, hexamers, and dodecamers.