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Show COLLEGE OF SCIENCE Michael H. Bartl TOWARDS BIOMIMETIC SELF-ASSEMBLY OF CUBIC LIPOSOMAL MEMBRANES Zachary J. Richens (Michael H. Bartl) Department of Chemistry University of Utah The research of photonic crystals operating in the visible spectrum of light provides n e w avenues for ultra-fast computers and higher-efficiency solar cells. However, to date the fabrication of highly effective photonic crystals has remained outside of our synthetic capabilities. The Bartl group has shown that several species of beetles use diamond-structured photonic crystals (the 'champions' of photonic crystal structures) to create their brilliant iridescent coloration. It is hypothesized that cellular cubic membranes direct the formation of these crystals in the insects' exoskeleton. Interestingly, cubic membranes have been detected in cells of many other organisms, for example, the mitochondrial inner membrane and other organelles of the giant amoebae, Chaos carolineses. These membranes morph upon starvation and in diseased states. Unfortunately, their phospholipid and protein composition can not tolerate the conditions necessary for light propagation. Inspired by these cubic membrane structures in amoebae, we have developed a protocol to harness this unique structural engineering in biology for the formation of stable, inorganic photonic structures. Our method does not destroy the various organelle membranes of C. carolineses while preserving much of the structure they assume during starvation. To stabilize and solidify the cubic membrane structures w e use tetraethyl orthosilicate (TEOS), a typical precursor for the sol-gel formation of glassy silica. By controlling the hydrolysis and condensation of TEOS in the presence of the cubic membrane structures w e are able to form a silica dioxide (Si02) layer around the membranes scaffold. Subsequent heating in an oxidative atmosphere removes the proteins and other organic molecules leaving an inorganic silica replica of the biological cubic template. SEM imaging was used to characterize the samples. Our method provides a first step towards the fabrication of inorganic photonic structures from biological membrane architectures. |