In the global medical textile market, biopolymers such as
chitin, chitosan, alginate, collagen and others have found invaluable
applications, affirms O L Shanmugasundaram
Medical textiles account for a huge market due to widespread
applications not only in
hospitals, hygiene and health care sectors, but also in hotels and other
environments where hygiene is required. It is known that microorganisms create
and aggravate problems in hospitals and other environments by transmitting
diseases and infections through clothing, bedding, etc. Thus microorganisms
exist in abundant quantities on textile materials. In order to combat these
adversities, it is highly desirable to impart antibacterial, antifungal
properties to textile materials.
The demand for special fibres produced from natural polymers
such as alginate, chitin or chitosan, starch, keratin or bio-synthesised
cellulose is quite high because of their unique properties and growing areas of
application. Fibrous materials always play an important role in special
application such as medicine.
Alginate fibres
Alginate is a natural polymer composed of two monomers, i.e.,
α-L-guluronic acid and β-D-mannuronic acid. Figure 1 shows the
chemical structures of these two monomers and the GG, MM and MG sequences in
the polymer chain.
Alginic acid consists of two monomers, D-mannuronic acid (M)
and L-guluronic acid (G). The relative proportion of mannuronic to guluronic
acid in alignate fibre significantly affects the properties of the end-product.
Alginate exists widely in brown seaweeds, acting as a
reinforcing element for cell walls. These fibres have unique gel forming
characteristics:
Upon contact with wound exudates, the sodium ions in the
wound exudates can exchange with the calcium ions in the fibres and as more and
more sodium ions enter the fibre structure, the fibres absorb more and more
water and form a gel. The gelled structure helps to keep a moist interface
between the dressing and the wound surface, which can assist the healing
process.
Alginate fibre has become one of the most important materials
for wound dressing. It is established that a moist condition is more suitable
for wound healing. When alginate dressing absorbs exudates from wound, a jelly
like material is formed and a moist environment is created during the course of
healing. At the same time calcium alginate rapidly releases calcium ions in
exchange for sodium ions on contact with blood, which stimulate both platelet
activation and blood coagulation to a greater, extend. In addition to
generating a moist healing environment, alginate dressings facilitate a high
absorbency of exudates from the wound.
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About the Author
The author
is a Lecturer with the Department of Textile Technology, KS College of
Technology, Tiruchengode, Tamil Nadu.
