We study the conformational change of insulin fibril growth from three aspects: the impact of (i) incubation time; (ⅱ) nano-particles; (iii) and ion added. We used circular dichroism (CD) spectroscopy and fourier transform infrared spectroscopy (FT-IR) to obtain the structural transition of the insulin, and gain the morphology information of fibril by atomic force microscopy (AFM) and transmission electron microscopy (TEM). We show that the insulin transform from £\-helix to £]-sheet structure as increased incubated time. The addition of Au nanoparticles (NPs) caused the formation of coordination bond with insulin fiber and produced shorter and thicker insulin fibril . The Fe3O4 NPs, on the other hand, offered only van der Waals interaction toward insulin fibril. Hence they could be used to separate insulin fibril from solution. Finally, addition of salts can induce the conformation changes of insulin fibril ten times faster than that without salts. And the insulin fibril fragment was two or three times shorter than that produced without salts. At high salt concentration, insulin formed amorphous aggregates. This phenomenon was attribute to anions from salt: covering the surface charge of insulin fibril, they weaken the original electrostatic repulsion among insulin fibrils and result in their aggregation.

In this report, electrostatic force microscopy (EFM), zeta-potential analyzer, circular dichroism Spectrophotometer and Fourier transform infrared spectroscopy are used to study the electrostatic property of surface on insulin fibril. EFM provides a simultaneous probe of topography and electrostatic property with highly local resolution in nanometer-scale. To understand the correlation between charge distribution on fibril surface and structure transformation, we controlled the incubation time and salt concentration. The results show that the surface charge increases with incubation time, and with the salt concentration increased, the pitch is found to decrease, variation of charge distribution are increased. In addition, we also have evaluated influence of amino acid sequence on growth rate of fibril associated with bovine, porcine and human insulin by atomic force microscopy and circular dichroism Spectrophotometer. The experimental results show that the number of hydrophilic groups on the peptide sequence will affect the speed of fibril generated, and the location of hydrophilic groups on the peptide sequence will affect the stability of the fibril under the frozen environment.

Includes bibliographical references (p. 107-121).

Thesis (M. Sc.)--University of Alberta, 2009. / Title from pdf file main screen (viewed on Dec. 11, 2009). "A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science, Department of Civil and Environment Engineering , University of Alberta." Includes bibliographical references.

Thesis (M.S.)--University of Delaware, 2009. / Principal faculty advisor: John L. Gallagher, College of Earth, Ocean, & Environment. Includes bibliographical references.

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published_or_final_version / Zoology / Doctoral / Doctor of Philosophy

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