Biomimetic Polymers for Chiral Resolution and Antifreeze Applications
341
Fig. 5.6. SEM images of chiral PV-L-Phe microspheres after crystallization of D; L-valine
(scale bars = 5 μm).^145
sulfamide [(R)-SA], were polymerized in catalytic microemulsion polymerization to give the
polymeric (S) PSA and (R) PSA, respectively, resulting in helical substituted polyacetylene.
This stage provides the authors with the particle’s core. In the second step, the shells were
formed via a sol-gel approach of TEOS (tetraethyl orthosilicate) in the same aqueous system.
The particles were shown to be optical active and the exhibited good thermal stability with
regards to the same core particles with a polymeric shell instead of a silica core. These
particles were used as chiral selectors for the chiral crystallization of the racemate system of
DL-alanine. The obtained particle (S)-PSA and (R)-PSA were reported as chiral selectors
toward D and L alanine respectively during chiral crystallization.
- Antifreeze proteins
Freezing is almost always lethal to cellular organisms as it deprives biological processes of
the aqueous medium they require, causes a concentration of ions and other solutes in the
plasma, induces denaturing of biomolecules, and ruptures cell membranes. Despite this,
polar and near-polar fish typically survive in seas where the temperature is subzero,
frequently as low as 1.9 °C. In a series of articles from 1953 through 1972, Scholander’s
group154-156 observed abnormally low freezing temperature of blood serum from Arctic fish,
and reported that this was not due to the presence of additional salts or other colligatively-
acting substances. Publications, first by DeVries et al. 157-159and later by others, described the
existence of a glycoprotein in the sera of Antarctic fish that lowered the freezing
temperature without increasing the osmotic pressure, which otherwise would have been
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