Poster
Presentation 14:
Biopolymer Synthesis for Optical Photonic
Crystals
Jessica Sinacola, Annette Shine, and
Anne Skaja Robinson
University of Delaware
Department of Chemical Engineering
150 Academy Street
Newark, DE 19716
sinacola@che.udel.edu
(302) 831-6697
The transmission of certain frequencies of electromagnetic
radiation can be controlled through the use of photonic crystals.
There are many optical devices, such as display screens and lasers, which
could benefit from the development of a cost-effective photonic crystal
tailored to visible light frequencies. Generation of a photonic crystal
suitable for optical applications can be accomplished by stacking several
layers of polymer molecules oriented perpendicular to a surface.
The polymer must be monodisperse, contain functional groups that can be
used for crosslinking and manipulation of polymer solubility, and exhibit
rigid rod behavior under the film deposition conditions. The rigid
rod behavior of alpha helical proteins combined with the monodisperse nature
of proteins produced from a cell make biopolymers strong candidates for
optical photonic crystals.
De novo genes were constructed for two alpha helical proteins
by head-to-tail ligation of synthetic DNA monomers. The artificial
genes were inserted into a plasmid that codes for an N-terminal S tag and
a C-terminal polyhistidine tag, both of which can be used for protein identification
and purification. A 15 kDa glutamic acid rich protein, corresponding
to 4 linked monomers, and a leucine rich protein, corresponding to 2 linked
monomers, have been expressed at high levels in Escherichia coli.
Significant differences in solubility have been observed between the two
polymers. The glutamic acid rich protein resides overwhelming in
the soluble fraction of the cell lysate, while the leucine rich protein
resides entirely in the insoluble lysate fraction. This indicates
that the glutamic acid rich polymer may be preferred for ease of protein
isolation and purification. The glutamic acid rich polymer has been
purified using immobilized metal affinity chromatography. Current
experiments are focusing on isolating larger genes and polymer secondary
structure verification via circular dichroism spectra.
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