Self assembly phenomena in collagen analogue materials

The collagen macromolecule is the basic building block that forms the foundation for all tissues in the body including skin, cartilage, bone, blood vessels, muscle, heart tissue, and eye tissue. The vast array of collagen tissue types and properties that can be achieved by varying the chemistry and structural architecture of one simple molecular building block introduces a very interesting paradigm in materials science. This paradigm involves the concept of synthesizing and using simple molecular scale building blocks, or molecular "Legos" to build complex hierarchical materials with tailored properties. Inorganic liquid crystals are a unique example of this class of materials. Inorganic liquid crystals are a very rare class of materials that have a lot of potential applications in smart material, photonic, and medical based devices due to the ability to externally control self assembly phenomena. A new type of inorganic liquid crystal has been synthesized in the biomimetics, orthopedics, and nanomaterials exploration (BONE) lab by aging mixed Al/sup 3+/Fe/sup 3+/ gels under hydrothermal conditions. The resulting aluminum oxide/iron oxide (AlFe) colloids are nanophase materials that exhibit shear induced and magnetic field induced particle orientation effects that are reminiscent of organic liquid crystals. The self assembly behavior of AlFe colloids was studied using small angle X-ray scattering and electrophoretic light scattering. The relative size of the AlFe particles strongly influenced the self assembly behavior. Interactions between AlFe particles and organic liquid crystals (phospholipids) were also investigated to serve as a precursor to AlFe/cell interaction studies. The influence of processing variables on the chemical and physical characteristics of the AlFe particles and a description of the unique self assembly behavior of these colloids in the presence of organic liquid crystals will serve as the focus of this presentation.