The Atomic Force Microscopy Study Of Self-assembled Structure Of Biomacromolecules

Biological macromolecules are important composition of organism, not only have larger molecular weight and complex structure, but also possess many attractive biological features and functions. Because of this, the development and application of biological macromolecules have become hotspot in research of the high molecular material and biotechnology. In this thesis, we selected type I collagen and chitosan as our main research object, based on the scanning probe microscopy imaging technology and self-assembly techniques, and chose atomic force microscope as the main research method, we studied the influence of metal cation on collagen, as well as solvent, temperature, p H, metal ions on the self-assembled structure of chitosan, got chitosan films of different size, thickness and hole quantity. The main contents of the work are as follows:1. Special ion effect of four different cationic groups was studied in the process of collagen self-assembly. Using NH4+, K+, Na+ and Mg2+ four different cation salts, we studied cationic groups in the process of collagen self-assembly, and first used the hoffmeister cation sequence as a detailed explanation. Experimental results showed that NH4+ and K+ belonged to kosmotropes and could increase the stability of collagen. However, Na+ and Mg2+ belonged to chaotropes, showed typical protein denaturant, could reduce the stability of collagen and changed the structure of collagen self-assembly. The thesis discussed the influence of various ions on collagen self assembly structure, hoping to provide reference for later research of development and application of collagen.2. Atomic force microscopy was used to study in a different polarity of the solvent effect on the structure and property of the chitosan. In the acetic acid and acetonitrile solution, by changing concentration, chitosan adsorpted and gradually formed chitosan fiber bundles and film on the mica surface. We also studied under the condition of different temperature and p H, chitosan in acetonitrile solution adsorpted and gradually formed the chitosan membrane on the mica surface. We just wanted to provide some useful information of chitosan membrane of post-processing method.3. We studied the structures and properties with different metal ions on chitosan, including Cu2+, Zn2+, Cd2+ and Mg2+, Ca2+, five metal ions. The chitosan self-assembled on mica surfaces with different ion concentration, chitosan adsorpted and gradually formed different chitosan membrane. The chelating ability of chitosan and heavy metals is stronger than alkaline earth metals. The adsorption quantity order of chitosan chelating metal ions is: Cu2+>Cd2+> Zn2+. We wanted to provide some useful information of chitosan treatment of heavy metal pollution.