ISSN 1070-4272, Russian Journal of Applied Chemistry, 2007, Vol. 80, No. 5, pp. 685! 694. + Pleiades Publishing, Ltd., 2007.
Original Russian Text + G.M. Mikhailov, M.F. Lebedeva, 2007, published in Zhurnal Prikladnoi Khimii, 2007, Vol. 80, No. 5, pp. 705!715.
Procedures for Preparing Chitin-Based Fibers
G. M. Mikhailov and M. F. Lebedeva
Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia
Received October 4, 2006; in final form, March 2007
Abstract-Data on preparation of chitin threads for the fabrication of absorbable suture materials, dressings,
and biodegradable substrates for the growth of human skin cells (keratinocytes and fibroblasts) are analyzed.
pyranose, is contained in shells and exoskeletons of
Crustacea and insects. This natural renewable polysac-
charide exhibits a set of unique biological properties:
it is enzymatically cleaved with lysozyme to form
N-acetylglucosamine and glucosamine; it shows anti-
microbial activity; it is a hemostatic, an immunomod-
ulator, etc. [13 4]. Like cellulose, which is the most
widely used polysaccharide, chitin is a fiber-forming
The use of chitin as suture material was suggested
by L.L. Balassa . He noted the capability of chitin
to promote wound healing. Studies of chitin-based
sutures confirmed that they fix tissues until the wound
is completely healed, after which they fully resolve
without leaving a trace. The resulting stitches become
cosmetic, without cicatrization of tissues [3, 4]. Chitin
is resistant to hydrolysis and is therefore stable in
prolonged storage. The sutures resolve in a patient’s
body in a time ensuring complete healing of a wound.
Despite apparent advantages of this polysaccharide,
there is still no commercial production of chitin-based
absorbable suture materials in the world because of
insufficient elasticity of chitin threads and certain
problems in the production process.
The information considered in this review concerns
preparation of chitin threads for the fabrication of
absorbable suture materials, wound textiles, and bio-
degradable substrates for the growth of human skin
cells (keratinocytes and fibroblasts).
The first attempts to prepare chitin solutions to
make fibers from them were made in the beginning of
the XX century. In 1926, Kunike  reported on the
first studies of chitin fibers. He dissolved chitin in
cold concentrated sulfuric acid and obtained 6310%
solutions. He used a wet procedure for thread forming,
with water, alcohols, or alkali as coagulants. After
drying the filament,
he obtained chitin fibers with
a density of 1.4 g cm
and a tensile strength of about
35 kg mm
Knecht and Hibbert  prepared films from a solu-
tion of chitin in concentrated HCl.
It is known that concentrated acids slowly dissolve
chitin with the simultaneous hydrolysis of the poly-
saccharide to oligomers and monomers. Orthophos-
phoric acid containing 15% water dissolves chitin
mildly, and in some cases brittle films can be prepared
from the solution .
Saturated solutions of salts capable of intense hy-
dration (LiCNS > Ca(CNS)
were tested as chitin solvents. With these solvents,
chitin was converted to a strongly swollen plastic
paste from which a fiber-like material was prepared
In 1936, Clark and Smith , using LiCNS as
chitin solvent and aqueous acetone as coagulant, pre-
pared a fiber; its characteristics, however, were not
reported. Further search for a chitin solvent led to
systems containing acids and organic solvents. Solu-
tions of chitin in a mixture of chloroethanol and
were used for forming fibers, with the precipi-
tation into water, methanol, or aqueous ammonia .
Attempts were made to dissolve chitin in solutions
of mono- and dichloroacetic acids; however, the re-
sulting threads showed poor strain and strength char-
acteristics because of strong hydrolyzing power of
In 1975, Brine and Austin suggested trichloroacetic
Filament is the amount of fibers corresponding to the number
of holes in a spinneret used for fiber forming; monofilament
is a fiber prepared using a single-hole spinneret, and polyfila-
ment, a thread prepared by twisting several filaments together.