Plastic is one of the most widely used materials in medical technology. Why is it like that? What are the benefits – and challenges – of this versatile material?
Plastic can not be thought out of our everyday lives. So it is when we get sick. Plastic as a material has revolutionized the treatment possibilities and patient safety in the field of medicine in an almost incredible way. Many life-saving measures would not be possible at all without plastic as a material.
The following article gives an overview of the importance of plastics in the medical field, here called medical technology because it is about products that are to prevent, alleviate or cure disease. A patch can have years of development behind it and be as high-tech as robots in surgery. What they have in common is that they would not exist without plastic as a material.
There are many benefits to using plastic in medical technology. Plastic has a low weight, does not absorb odors and is resistant to water and other liquids. In addition, there are many plastics and they can be shaped in many different ways to be adapted to each purpose. Therefore, plastic is used in many different areas in medical technology.
Plastic has made the job of doctors and healthcare professionals much easier. Syringes, needles and infusion sets had to be sterilized for decades before they could be used again, which was time consuming and costly. Today, plastic-based medical aids are sterile-packaged available where they are needed, and they are usually thrown away after they have been used. This not only facilitates the job but also contributes to higher safety. The sterilization of plastic products in medical technology can be accomplished by various techniques. Radiation or ethylene oxide? It is the method that makes the difference.
Adaptation to individual needs
Plastic is a highly adaptable material for the individual needs of doctors, nurses and patients. Manufacturers of medical devices or consumables work with the most modern design and production methods, which enables a precision-adapted production of medical plastic products. In addition, plastics for medical technology can be produced at very low costs. Plastic is easy to handle, unbreakable and skin-friendly.
Plastic has also reduced the risk of allergies that can occur when using nickel or aluminum instruments and surgical cutlery. A large range of different plastic materials are available for medical devices. All instruments and aids are very practical and optimized for each application area. The possibilities of use are versatile and in the development of the products great emphasis is placed on keeping the patient impact as low as possible.
Plastic in medical technology – a long success story
The use of plastic in medical technology dates back many years. Classic recyclable materials were gradually replaced decades ago by the lighter plastic. An important role in this context played the fact that plastic is so cheap to manufacture that it can be thrown away after being used once. Both of these criteria led to plastic now being available in all areas of modern medical technology.
High-performance plastics for the special requirements of medical technology
In medical technology, various plastics are used, all of which have been tailored for their intended use. Thermoplastics are particularly useful because of their versatility and good machining capabilities. They have insulating properties and are stable, which enables, for example, a very precise dosing of drugs through resealable infusion bags, crease-free breathing tubes and syringes. Orthoses, prostheses and individually adapted parts for, for example, hearing aids are also made of thermoplastic.
PEEK plastics are high-performance plastics that impress with their very good thermoplastic properties and high temperature resistance. PEEK is therefore widely used in medical technology. The conditions under which this type of plastic is used are often very harsh – for example for surgical instruments. Time is of the essence in the operating room and the doctor must without exception be able to trust his tools. PEEK thermoplastic is a material that meets these high requirements. Due to its robust properties, it is used in dentistry and as a material for implants. The latest development also enables 3D printing of PEEK.
Bioplastics and biocompatibility
Nowadays, bioplastics are also used in medical technology, with the aim of reducing the impact on the environment. Due to the intensive use of plastics in medical technology, the amount of waste has also increased sharply. Biodegradable plastic is an important contribution to protecting the environment.
Biocompatibility, on the other hand, is a question of how the human organism tolerates a material. The material must be certified according to ISO 10993 1-20, a standard that aims to protect the patient and is certified by so-called notified bodies. With the help of coatings, non-biocompatible plastics can also be made biocompatible.
Silicone
Silicone is a material that is both flexible and durable, and therefore fits very well for the needs of medical technology. A variety of tubes and couplings used in healthcare are made of silicone. Breast implants are also made of silicone. However, the so-called PIP scandal made silicone infamous, when the French implant manufacturer Poly Implant Prothèse (PIP) used unapproved industrial silicone instead of certified medical silicone. The result of these criminal activities was thousands of affected women in Germany and France. However, this is an isolated case that should not affect the knowledge that silicone is an approved material for medical applications. Silicone is especially good as a material for the interconnection of hard and soft components.
ABS
ABS is also widely used in medical technology. ABS is a very impact-resistant thermoplastic that, like PEEK, can withstand very high temperatures. It is also completely unbreakable. In addition, fiberglass reinforcement is increasingly used, which further increases the impact strength. This is especially important for emergency situations, where doctors can hardly care about a gentle handling of the equipment but must focus their attention entirely on the treatment of the patient. Therefore, impact-resistant and reliable equipment saves lives. High quality plastics make a very important contribution to this.
Health risks
No health risks from medical plastics
Apart from the PIP scandal, most plastics do not pose any health risks. Unlike metal, plastic does not trigger allergies. However, it is important that certain things are taken into account in production. For example, the plastics used in medical technology should not contain bisphenol A or phthalates. The raw material suppliers take this into account.
Plastics för medical applications
Plastic for medical applications is used, for example, for implants and for tubes. Plastic covers are used to protect medical equipment. Healthcare professionals and patients come into contact with plastic every day. For example, syringes and medical spoons are made of plastic – and thrown away after use. Plastic medicine containers are also very practical because they have a low weight and are very robust. Due to the low production costs, they can also be thrown away. The previously necessary and resource-intensive cleaning is not necessary.
Medical implants are used for aesthetic or therapeutic reasons. Particularly well-known are silicone breast implants for women who have contracted breast cancer or who for psychological reasons want a breast change. Plastic for medical implants is also used in other areas. And then there are implants that give the patient the hearing back. For hearing aids or as hearing protection in environments with loud noise, medical plastic parts are used that can be inserted into the ear. Not to mention artificial joints as well as bone plates, bone screws and bone nails made of plastic. Sometimes these are already made today as custom-made unique to the individual patient’s needs through the technology 3D printing, also called additive manufacturing.
Hoses and clamps
Seriously ill patients often have to use a catheter that is also made of plastic. The high skin tolerance, the low weight and the flexibility are ideal properties for a catheter. Because the plastic does not change even when it is in the body, it can remain for months or even years.
Doctors and nurses in hospitals and health centers also use medical tubing daily. They are needed for blood tests and for breathing or for infusions. Medical tubing is often transparent so that the fluid inside can be monitored at all times. They can be manufactured in different lengths and thicknesses and thus adapted exactly to individual needs. In addition, plastic hose clamps are used and other materials are no longer used. The hose clamps are needed to stop the supply of blood or fluid. They can easily be locked and removed. The hose clamps are optimized for reuse. They are available in different colors and are therefore easy to distinguish.
Plastic housings
Plastic in device housings cannot be replaced in medical technology. The covers are used to transport and protect sensitive medical equipment, which is used, for example, en route in emergency situations. But even stationary equipment, devices and instruments with sensitive electronics used in hospitals are protected by plastic casings. The health center’s instruments as well as blood preserves or blood plasma are also stored and transport protected by plastic casings. The benefits are obvious because plastic is easy to clean, robust, weather resistant and very stable. Taken together, these properties constitute ideal conditions for protecting important instruments and equipment from external influences.
Manufacturing technology
Injection molding
Medical technology places very high demands on the plastics industry, which must be met. In recent years, the possibilities of plastic technology have increased sharply. High precision is required, as many parts have a very small size and weight. Since modern machines are used, it is possible to manufacture even the smallest parts with complex geometries. At the Fakuma Trade Fair for Plastics Processing this was clearly demonstrated last year: large injection molding machines produced very small components.
The most commonly used process for large volumes of medical devices is injection molding in injection molding machines, which are now often operated entirely electrically or as hybrids instead of hydraulically.
A large number of plastics are very well suited for injection molding. These plastics are melted and softened by heating so that they can then be shaped as desired. It is possible to produce everything from small and medium-sized to large series of several million parts per year.
Extrusion and welding
A completely different process is extrusion. Among other things, hoses, films and bags are produced with this technology. Again, the starting material is melted first, but unlike injection molding, the melt is not injected into a mold but is continuously pressed through nozzles with different geometries before it is cooled to the desired shape and solidifies.
A complement to the mentioned manufacturing methods is plastic welding. Like the classic metal welding, plastic can also be welded together by melting. Plastic welding is suitable both for series production and for individual parts.
Material suppliers are good advisors
The materials available from the suppliers meet current standards. They are selected by the manufacturers according to their needs. Plastic comes in many varieties, some are soft and flexible while others are very hard and robust; they do not bend and offer very good protection when transporting sensitive instruments or organic substances needed for the patient’s treatment.
In medical technology, mainly plastics are used that are perfectly adapted to the product. These can also be composites, ie plastics that are mixed with various additives during production. The suppliers always offer a selection of different materials and can give individual advice on which plastic is particularly suitable for a particular product. There are hundreds of suppliers of composites in Europe. Choose a supplier with good experience of medical devices and who can offer the best plastic materials. Then you can be sure that the materials are perfectly adapted to the intended use.
This is a translated and edited article from DeviceMed.
Photo: Sara Magnusson/Tingverken
