The discovery of polytetrafluoroethylene (PTFE) is an excellent example of a fortuitous accident. In 1938, Dr. Roy Plunkett, a Dupont chemist who was endeavoring to create a new type of chlorofluorocarbon based refrigerant unintentionally stumbled upon PTFE. In the span of less than ten years, this substance was being used in a wide variety of commercial products.
Through the decades, PTFE has served many important purposes ranging from creating well sealed pipe fittings to preventing the leak of radioactive substances to a coating for everyday cookware. PTFE continues to be an extremely important substance with applications in many industries including the medical field.
What Exactly Is PTFE?
PTFE is a synthetic (artificially generated) fluoropolymer. Due to the electronegativity of fluorine, it is hydrophobic which means that it repels water. PTFE also has a very low coefficient of friction which makes it an ideal material for devices and applications where friction needs to be minimized. The chemical bonds in PTFE are very strong which means it is an inert and durable substance that resists corrosion from heat, water, or exposure to chemicals.
What Are Its Uses In the Medical Field?
Due to its valuable properties, PTFE is often utilized in medical technologies where precision, efficacy and quality of materials are paramount. Common medical applications of PTFE include:
Guidewires, Hypotubes and Mandrels
PTFE coated guidewires, hypo tubes, mandrels and other small wires are utilized in the majority of medical procedures from simple catheterizations to complicated, invasive surgeries.
PTFE coated wires can drastically reduce the friction of medical instruments which aids in patient safety. Since guidewires often travel through delicate human vasculature, guiding stents, balloons, catheters and other surgical instruments, minimizing friction is essential. Controlling the coating thickness and maintaining uniformity of the applied coating is crucial to the device manufacturer.
It is imperative to have the optimum adhesion to the coating that PTFE offers while providing the low coefficient of friction. The use of robotically applied coating helps to make the PTFE coating more consistent in thickness. With this accurate application of coating, physicians and health professionals are able to get a “consistent feel” for manually inserted devices that are PTFE coated.
PTFE is also often used to coat medical instruments that have cutting edges such as scalpels and other surgical blades. This coating essentially lubricates the cutting edge which reduces cutting forces, resulting in a smoother, neater incision. This is obviously beneficial to the surgeon but is also advantageous to the patient since coated blades result in less noticeable post-operative scars.
It’s easy to become confused about the safety of traditional nonstick coatings because of inaccurate newspaper articles, TV reports, and advertising claims. However, this should clarify the inherent safety of traditional nonstick coatings on medical devices such as guidewires, hypotubes, mandrels and needles.
PTFE and PFOA are NOT the same
Polytetrafluoroethylene (PTFE) is a type of fluoropolymer commonly used to create a nonstick surface on medical devices. PTFE is also an essential component in items such as automobiles, airplanes, mechanical and electrical equipment, oilfield equipment, pollution control equipment, fire-resistant wire insulation, and various household items. The FDA (Food and Drug Administration), NSF (National Sanitation Foundation), the EPA (Environmental Protection Agency) and other regulatory agencies all make clear that PTFE is completely safe for people and the environment.
PFOA (perfluorooctanoic acid) is a fluorochemical that has been used as a processing aid in the manufacture of PTFE. In recent years, the US EPA became concerned about emissions of PFOA into the environment; consequently, the EPA intends to regulate the use of PFOA by December 31, 2015.
In the meantime, the EPA has stated: “The information that EPA has available does not indicate that the routine use of consumer products poses a concern. At present, there are no steps that EPA recommends that consumers take to reduce exposures to PFOA.”
PFOA Stewardship Program
As a result of the EPA’s concerns about PFOA, six major fluoropolymer manufacturers joined with the EPA in a voluntary program to “work toward the elimination of PFOA from emissions and products by the end of 2015.” The program is referred to as the “2010/2015 PFOA Stewardship Program” and the manufacturers appear to be on track to meet the goals of eliminating PFOA in PTFE manufacturing by December 31, 2015.
The Stewardship Program does not impact the use of PTFE in any applications. Moreover, the EPA does not intend to ban or restrict the use of PTFE. PTFE coatings for medical devices are here to stay.
License: Creative Commons
George Osterhout is the President of Surface Solutions Inc., handling precision CNC machining needs.