What are Biomedical Textiles

Biomedical textiles are textile products and constructions, for medical and biological applications. They are used for first aid, clinical or hygienic purposes.  Examples of their application are:

• Protective and healthcare textiles: surgeons’ wear, operating drapes and staff uniforms, etc.

• External devices: wound dressings, bandages, pressure garments, prosthetic socks, etc.

• Implantable materials: sutures, vascular grafts, artificial ligaments, etc.

• Hygiene products: incontinence pads, nappies, tampons, sanitary towels, etc.

• Extracorporeal devices: artificial liver, artificial kidney, artificial lung, etc.

The design of a biomedical textile is driven by its end function. The main factors include:

• Function: the textile needs to fulfil the purpose for which it was designed, for example swabs require an absorbent textile, sutures may require a biodegradable textile, while hospital bedding should be comfortable and durable.

• Biocompatibility: this refers to the reaction of the textile with blood and tissue in the body. An implantable device has more potential for reaction than an external device and is, therefore, subject to tighter regulations. For example an artificial ligament is permanent and is able to react with blood cells and the surrounding tissue, compared to an external bandage that is temporary and only contacts the outer skin tissue.

• Cost: this will depend on the raw materials, manufacturing process and product end-use; surgeons’ gowns and swabs should have a low production cost while vascular grafts and artificial skin will have a relatively high production cost.

• Product approval: each country has its own regulations and standards for medical textiles. However the European Union has introduced Community Legislation to govern medical devices. The three directives are: Active Implantable Medical Devices, Medical Devices Directive and In-Vitro Diagnostic Medical Devices.

Biomedical textiles are manufactured from a wide range of processes. Extruded polymers can be further processed or used as filaments or tapes in dental floss and toothbrushes. Braided textiles are used for sutures and to replace damaged tendons and ligaments. Woven and knitted materials are used extensively in bandages, vascular grafts and hernia meshes. A specialised area of medical textiles is the extrusion of hollow fibre membranes used in extracorporeal devices. Non-wovens are primarily made from synthetic fibres and uses include wound dressings, hygiene products and protective clothing.

Various synthetic and natural fibres, each with unique properties, are used to construct biomedical textiles. Fibres are used in a variety of applications depending on the characteristic required; for example carbon fibre known for its absorption properties is used in wound dressings and absorption columns. However it is used for its strength in artificial ligaments and for its lubricity in orthopaedic cushioning. Synthetic polymers, used extensively, can be divided into permanent e.g. polyamide, polyester, polyethylene, polypropylene, PTFE and polyurethane and biodegradable which are mainly used in sutures and tissue engineering structures e.g. polycaprolactone, polyglycolic acid and polylactic acid. Natural biological fibres include: chitin (from the cells of crustacea) a polysaccharide renowned for its wound healing properties and incorporated into wound dressings; collagen (a fibrous protein found in connective tissue, tendons, etc.) used in cell engineering structures, for example artificial skin; and alginate fibres which can interact with the wound to form an absorbent gel, that acts as a protective barrier and still allows the wound to breathe.