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Polymeric Medical Materials
Polymeric materials are used in medical devices because of their
unique properties, ease of manufacture, flexibility in design and
low cost. Unique properties include:
- Flexibility (tubing, seals, vascular...)
- Sorption/diffusion (drug delivery, contact lens...)
- Formability (bone cement, dental fillings...)
- Wear resistance (prosthetic joints...)
- Specific stiffness of composites (crutches, wheelchairs...)
Polymers have been successfully used to aid repair and modification
of the human body. The applications for polymers in the medical field
cover an enormous range. Some example application areas are: Cardiovascular
(heart valves, heart assist devices, blood vessel prosthesis, stents
etc.), Internal Artificial Organs (kidney, lung, muscles etc.) Skin
and Soft Tissue (skin, wound care) Ophthalmic and Craniofacial (contact
lenses, cornea implants, facial surgery), Orthopaedic and Dental
(joint replacement, limb replacement, dental implants) and mobility
aids (crutches, wheelchairs).
Materials selection
Only a small number of polymers are available as medical grades
for medical applications and an even smaller number are used for
implants. The choice of polymer depends on the extent of contact
with body fluids, internal and external tissue as prescribed by the
regulatory framework. In addition, thermal and mechanical properties
and possible degradation over time must also be taken into consideration.
Typical polymers and their uses are listed below. |
Materials |
Application |
PVC, PA, PE, PS, Epoxy Resins |
Non-contact: e.g. syringes, blood storage bags |
Silicone Rubber, Natural Rubber, PVC, Polyurethane, PE, PP, Polyester |
Short-term contact: e.g. catheters, feeding tubes, drainage tubes |
Nylon, PP, Polyester |
Medium-term contact: e.g. sutures and ligatures |
PE, PET, Silicone Rubber, Polyurethane, PMMA, Polysulphones, Polyphosphazenes,
Hydrogels, Thermoplastic Elastomers Polydimethylsiloxane (PDMS) |
Long term contact: Implants |
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