Our 13th Year of Publication
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Cover Story

Polymeric Biomaterials :
With Improved Biocompatibility And A Greater Range Of Applications

Once limited to routine applications such as sutures and dental fillings, the latest biomaterials have become more functional and are able to substantially mimic body tissues, enabling their use in steerable vascular devices and biomimetic polymer-coated metallic implants. The European Society for Biomaterials has defined Biomaterial as any “material intended to interface with biological systems to evaluate, treat, augment, or replace any tissue, organ, or function of the body,” biomaterials made of advanced metals, polymers, ceramics, and other materials can powerfully treat a range of degenerative diseases.

Like metals, polymers also have a long history as biomaterials. The potential biocompatibility of polymers was discovered during World War II, when pilots occasionally fell victim to shards of polymethyl methacrylate from shattered aircraft canopies. Physicians treating the soldiers found that the accidentally implanted polymer was well tolerated by the pilots. Now the largest segment of the biomaterials market, polymers’ success in medical applications is a result of their relatively low cost and their functionality.

The advantages of polymers are :

  • They can be formulated to meet determined characteristics

  • Polymers can be produced that resist bacterial infection, that biodegrade, and that deliver drugs

  • They have fewer limitations than metals or ceramics.

  • With the right chemistry set and a commitment to innovation, a scientist can design almost anything with polymers

Following are some of the recent developments in the field of Polymeric Biomaterials.

Silicone Polymers

Silicone polymers are one example of a family of polymers that may be suitable materials for various healthcare applications such as urological catheters and wound drains. As a result of their biocompatibility and mechanical properties, liquid silicones have been found to be excellent for use in injection moulding of various device components. Elastomers can be extruded into tubing sections, enabling design freedom for OEMs and fabricators. Combined with these substrates, liquid silicone coatings can be applied where reduced friction is desired.

With increased focus on innovative device solutions, customization of materials help customers meet specific application requirements. For example, the incorporation of rediopaque additives into silicone elastomers enables the detection of devices under X-ray. Formulation optimization, allowing for a specific look and feel of material, is another consideration. Special adhension promotion packages can be incorporated into silicones, allowing these materials to be bonded to a variety of plastic and metal substrates.

Electroactive polymers

The recently developed electroative polymers expand when subjected to a small amount of voltage. When the voltage is removed or reversed, the polymers contract to their original proportions. Electroactive polymer components can generate movement and exert force, providing functionality for medical device applications which can be used development of active and controllable medical devices.

Currently, the primary applications of the electroactive polymers are angioplasty and other vascular applications involving guidewired and catheters. Using electroactive polymers, vascular devices can be accurately steered through narrow and tortuous blood vessels. Components also can be designed to deliver drugs and hold and release objects such as wires.

Some more product opportunities have been identified in such marked segments as cardiac rhythm management, neuro intervention, drug delivery and vascular surgery.

The electroactive polymers are the product of almost 20 years of research. In 2000. Alan Heeger, Alan Macdiamid, and Hideki Shirakawa were awarded the Nobel Prize for the discovery of electroactive polymers.

PC Film Withstanding Gamma and E-beam Radiation :

With the help of a special additive. A polycarbonate him is provented tom turning yellow when exposed to high-energy radiation. It is transparent and exhibits high impact strength and stiffness. To be extruded from a special grade of polycarbonate. The material statistics the biological compatibility criteria specified in the US Pharmacopeia. It is suitable for devices that come into contact with body fluid or tissue for up to 30 days. The film is also used to manufacture blood-heat exchangers; its transparency enables blood flow to be checked visually. The film is available in thicknesses ranging from 175 to 500 mm; other thicknesses and surface structures can be specified to suit other applications. The top and bottom of the film have a glossy finish.

Plastics for Optical Implantations

Polymers for ophthalmic implantation are used for hydrophilic foldable intraocular lenses. An implantable grade of polymethyl methacrylate (PMMA), available in rod and sheet form, can be processed by means of CNC lathes and laser cutters into a range of custom shapes and sizes. Hydrophobic materials for foldable intraocular lenses and implantable custom acrylic polymers are also available.

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