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.