Chitin
nanofibers are prepared from the exoskeletons of crabs and prawns by a simple mechanical treatment after the removal of
proteins
and
minerals
. The obtained nanofibers have fine nanofiber networks with a uniform width of approximately 10–20 nm and a high aspect ratio. The method used for
chitin
-nanofiber isolation is also successfully applied to the cell walls of mushrooms. They form a complex with
glucans
on the fiber surface. A grinder, a Star Burst atomization system, and a high speed blender are all used in the mechanical treatment to convert
chitin
to nanofibers. Mechanical treatment under acidic conditions is the key to facilitate fibrillation. At pH 3–4, the cationization of amino groups on the fiber surface assists nano-fibrillation by electrostatic repulsive force. By applying this finding, we also prepared
chitin
nanofibers from dry
chitin
powder.
Chitin
nanofibers are acetylated to modify their surfaces. The
acetyl
DS can be controlled from 1 to 3 by changing the reaction time. An
acetyl group
is introduced heterogeneously from the surface to the core. Nanofiber morphology is maintained even in the case of high
acetyl
DS. Optically transparent
chitin
nanofiber composites are prepared with 11 different types of acrylic resins. Due to the nano-sized structure, all of the composites are highly transparent.
Chitin
nanofibers significantly increase the Young's moduli and the tensile strengths and decrease the thermal expansion of all acrylic resins due to the reinforcement effect of
chitin
nanofibers.
Chitin
nanofibers show chiral separation ability. The
chitin
nanofiber membrane transports the D-isomer of
glutamic acid
,
phenylalanine
, and
lysine
from the corresponding racemic
amino acid
mixtures faster than the corresponding L-isomer. The
chitin
nanofibers improve clinical symptoms and suppress ulcerative colitis in a DSS-induced mouse model of acute ulcerative colitis. Moreover,
chitin
nanofibers suppress myeloperoxidase
activation
in the colon and decrease serum interleukin-6 concentrations.
This article is Open Access
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