Medical Textiles

Medical Textiles are used in the protection for healthcare professional from containment fluids, the major requirements for medical textiles are that it should be biocompatible and should be comfortable. Medtech materials are used by doctors, textile chemists and technologists. These products are generally 70% disposable and 30% reusable.

Specialty fibers and commodity fibers are used in the manufacturing of medical textiles.

Important characteristics of Medical Materials:

Mechanical properties: These properties include durability, strength and elasticity of the fibers used in the materials.
Non-toxicity: This is the most important property considered during the production of medical textiles. It is ensured that the material used should not cause rise in the body temperature, allergic reaction, any kind of inflammation and should be non- toxic in nature.
Ability to be sterilized: This property deals with the clean ability of the material as it may be contaminated with bacteria.
Biocompatibility and optical properties: The materials used should be bio-inert and bioactive. Also it should posses optical properties for contact lens purpose specifically.
Diffusion properties: It is an essential property for controlled drug delivery systems and membranes like in the artificial kidneys.

Fibers used in Medical textiles:

In medical textiles, different types of fibers are used as per there area of applications, like specialty fibers, commodity fibers, biodegradable fibers and non-biodegradable fibers.

Specialty fibers: This type of fibers include Chitosan, Chitin, Collagen and calcium Alginate fibers.
Commodity fibers: Commodity fibers are further classified into two categories, natural fibers and synthetic fibers. Natural fibers include silk, cotton, viscose which is used as non- implantable materials and for hygiene products. Whereas, the synthetic fibers include polyamide, polypropylene. PTFE and carbon.
Biodegradable fibers: These fibers can be absorbed by the body within 2-3 months after implanting them. Includes polyamide, collagen and alginate.
Non- Biodegradable: Include polyester, PTFE carbon as the name suggests the fibers do not degrade and are used for external use only.

Specialty Fibers used in Medical Textiles:

Chitin: It is a polysaccharide obtained from insects, lobster shells and crab. It is used as artificial skin dressings. Has good healing properties and are absorbed by the body, less painful and contributes in new cell formation.
Chitosan: It is obtained by alkali treatment of chitin and can be sun into filaments. It s generally used for slow drug release membranes.
Calcium Alginate fibers: It is obtained by laminariae seaweed; it is no- toxic, natural and biodegradable. It is effective in wound healing.
Collagen: Collagen is obtained from bovine skin; it is basically protein that is either fiber or hydro gel. It is as strong as silk and can be used as sutures.

Classification of Medical Textiles:

Medical textiles are classified under four main categories, namely:

Health care/ Hygiene products: Used for bedding cloth, surgical gowns, wipes, cloths etc.
Implantable materials: This includes sutures, artificial joints, artificial ligaments and vascular grafts.
Non-implantable materials: Wound dressing, plasters, bandages etc.
Extracorporeal devices: Artificial lungs, liver and kidney.

Major Products / Materials of Medical Textiles:

Wound dressing:

This includes the following products:

Wadding: It is a high absorbency material which is covered with no-woven fabric to prevent wound adhesion or fiber loss.
Lint: Lint is basically a plain weave cotton fabric used as a protective dressing for mild burns.
Gauze: Gauze is an open weave absorbent fabric which is coated with paraffin wax, used for the treatment for burns.

Bandages:

Bandages are used for various applications; it helps to keep the dressing over the wound.
Bandages can be woven, knitted or non-woven, warp and weft knitting is used to produce tubular structure. Can be elastic or non-elastic in nature.
The elastic yarn provides comfort and support in the bandage structure.

Sutures:

It falls in the category of implantable materials. Sutures are multi or mono filament threads used to close wound, tie bleeding vessels or join tissue.

Sutures can be further classified as absorbable and non- absorbable.

An absorbable suture is made by using collagen, acid copolymer, polyglycolic acid etc. and is used for internal wound closing.
Non- absorbable sutures include polypropylene, polyester and silk used for closing external wound and are removed by healing.
Important properties required for sutures: Knot pull tensile strength, knot diameter, knot security, surface roughness and knot run down.

Health care/ Hygiene products:

It includes operating textiles, barrier products, surgeon, nurses’ caps and gowns, breathable membranes, foot wear and cloths etc.
The main function of these products is to protect health care professionals from contamination by blood and other fluids which can be infectious.

Dental Biomaterials:

The regeneration of tooth tissue is no possible hence the biopolymers are used in dental treatments to substitute for defects in tissues.
The requirements of dental polymer is that it should be transparent, stability, offer good resilience, insoluble in oral fluids and should have softening point.
The most widely used polymer is polymethylmethacrylate.

Artificial kidney:

The blood is circulated through a membrane which is a flat sheet of hollow regenerated cellulose fibers in form of cellophane to filter waste material.
Here, multilayer Filters are used which is composed of needle punched fabric with different densities.

Other Medtech materials / products include, protective garments, mechanical lungs, artificial liver, Vascular implants, tendons, ligaments, biomaterials in ophthalmology.