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Three Common Medical Applications for Parylene

July 1, 2023

Parylene conformal coating boasts a multitude of benefits and properties that make it an appealing choice for a variety of medical device applications. Chief among Parylene’s advantages for medical applications, however, is that it meets USP Class VI and ISO 10993 biocompatibility requirements—a characteristic that is essential for many critical medical products.

Additional benefits of Parylene include;

  • Excellent moisture, chemical, and dielectric barrier properties
  • Pinhole-free coating
  • Tin whisker mitigation
  • Minimal increase in weight and volume
  • Dry-film lubricity
  • Penetration of crevices and small nooks
  • Adhesion to a range of substrate materials
  • Thin and truly conformal coating of a substrate
  • Compatible with sterilization options that include EtO, gamma, autoclave, peroxide plasma and E-beam

In the case of medical implants or medical devices that are inserted into the body, Parylene performs double duty by protecting them from direct exposure to the harsh environment of the human body while protecting the human body from the foreign medical device. Three such types of medical products that benefit from Parylene’s unique blend of properties are highlighted below.

Catheters

Catheters, which are inserted into the body for a variety of reasons, reap the benefits of Parylene’s proven biocompatibility and barrier properties. Parylene conformal coating most notably lends a low coefficient of friction that translates into enhanced lubricity for these medical devices. Imparting lubricity nearing that of PTFE, Parylene conformal coating of catheters facilitates smooth navigation of the tortuous curves of the human body.

Cardiac-Assist Devices

Parylene protects electronic cardiac-assist devices like pacemakers and implantable cardioverter-defibrillators (ICDs). This thin, conformal coating encapsulates the sensitive electronics, safeguarding them from the damaging effects of bodily fluids. This protection is crucial for the devices to function reliably over a long period.

The benefits of Parylene extend beyond just protection. It creates a barrier between the implant and the body, preventing exposure to potentially harmful materials. As a dielectric, it also isolates the electronics from the body’s electrical signals, ensuring proper device operation.

Stents

Because of the vapor deposition polymerization (VDP) process by which it is applied, Parylene conformal coating is prized for being highly conformal, yielding a uniform thickness. This makes it particularly useful for coating complex geometries like stents. Parylene has risen to prominence in the stent field in recent years due to its ability to enable controlled drug release and act as a bonding agent or tie layer on drug-eluting stents. In this latter capacity, the Parylene coating is leveraged because it adheres well to both the bare metal stent and the therapeutic agent.