A substance known as chitosan, which can be derived from the shell of crabs, is being researched at the Council for Scientific and Industrial Research (CSIR), in Port Elizabeth, for use in bandages and to develop low-cost, high-performance nanofiber-based wound dressings.

The substance has been found to possess favourable antibacterial activity against S. aureus and E.coli, bacteria commonly associated with wounds.

Chitosan, a derivative of chitin found in the crab shells, is a biocompatible, nonantigenic and biofunctional polymer and is known for its antimicrobial properties, biodegradability and nontoxicity associated with wound healing.

CSIR research scientist Valencia Jacobs explains that chitosan nanofibres are fibres with a diameter in the nano range (10-9), a billionth of a metre and thousand times thinner than a single human hair. They have unique properties including a large surface area, which could contribute new surface functionalities to the traditional fibres. The nanofibres are produced from the polymer solution by introducing electrostatic fields into the solution through a process known as electrospinning.

"These nanofibres have a large surface area to mass ratio, high pore volume and small fibre diameter which make them suitable in wound care application by providing significantly enhanced moisture management, oxygen permeability, barrier properties, and bioactivity.

"In essence, nanofibers are intrinsically delicate and difficult to handle therefore they need a structural support, such as conventional wound dressing," she explains.

The traditional form of wound dressing is cost effective and consists of textile-based wound dressings such as gauze and wadding, and their functions comprise some level of absorbency and wound protection.

The advanced form of wound dressing is expensive and comprises films, hydrocolloids, hydrogels and alginates. Their functions include moisture and bioactivity.

Whereas, combinations of electrospun nanofibers with traditional textile wound dressings may offer the benefit of improved functionality, while maintaining the conformability, good absorption, flexibility and low cost associated with traditional bandages.

Chitosan can also be used in a broad range of applications, including tissue engineering, food, filtration and various chemical industries.