Medical coatings improve performance and protect patients
The medical industry continues to grow and introduce new technologies to the healthcare sector – including medical coatings. In particular, the increased use of medical devices (surface devices, external communicating devices, and implantable devices) means that there is a burgeoning market for medical device coatings, designed to improve lubricity, reduce friction, and eliminate corrosion and wear for the device and increase performance and comfort for the patient. As well as medical devices, medical coatings are used for implants, medical equipment and tools, and each application comes with its own demands in coating properties and biocompatibility.
Medical coatings can be divided by function into lubricants, antimicrobial, and hydrophilic. In this article we will look at the different medical coatings functions, the coatings used for each, and the companies providing medical coating services in the UK.
The 3 types of medical coatings: lubricants, antimicrobial, and hydrophilic
Like any coating, medical coatings need to be able to perform based on the environment, substrate, and end use to which they are put. Not all medical applications have the same needs and requirements, which is why there are three main types of medical coatings: lubricants, antimicrobial, and hydrophilic.
Lubricant medical coatings – reduce friction
A dry film lubricant coating provides several important functions for medical devices and equipment – it reduces friction and so prevents premature wear, increases dependability, prevents substances sticking to instrument surfaces, minimises insertion forces, and provides a smooth surface in order to prevent fretting. Devices that might use a lubricant coating include catheters, stents, hypodermic and suture needles, wound drains, feeding tubes, endotracheal tubes, dilators, guide wires, and many more.
The coating technologies used for lubricant medical coatings are varied and include silicone-based coatings, fluoropolymers (non-stick coatings such as PTFE or Teflon), molybdenum disulphide (also known as kashima to cycling enthusiasts), and ceramic coatings.
Antimicrobial medical coatings – actively fight infection and disease
An antimicrobial medical coating works to fight infection through the biocidal action of copper, silver, zinc, or organic additives. These materials prevent the buildup of microorganisms (bacteria, fungi, viruses) on a surface and kill those they come into contact with. They do this through a number of mechanisms, including preventing respiration and actively destroying cells.This is important because these surfaces come into contact with bodily fluids. By inhibiting microbes these coatings protect patients from the risk of infection being carried on medical devices.
As well as the different biocides, there are a number of different coating technologies used for antimicrobial medical coatings including epoxy, polyurethane, and powder coating. These coatings are applied to walls, floors, frequently touched surfaces such as doorknobs, bins, and elevators.
Hydrophilic medical coatings – permanently slippery
Increased wettability is a desirable function for a number of medical devices. Wettability is the ability of a surface to reduce the surface tension of a liquid, allowing it to spread and wet the surface. What this does is reduce friction, enhance lubricity, wets evenly, and allows interaction between a device surface and, for example, vessel walls. They reduce abrasion and damage during exploratory procedures (with guidewires for example), and allow even spreading of samples and improved diagnostics.
Hydrophilic coatings are applied through dip coating, spray coating, film coating, and in some cases, chemical vapour deposition. The two main technologies used are polyvinylpyrrolidone (PVP) and hydrogel-based coatings with hyaluronic acid (HA).
Case study: Parylene medical coating
Parylene has been used for medical device coatings for nearly 40 years and it is still a go-to conformal coating in the industry. “Parylene” refers to a variety of chemical vapor deposited polymers and it works as a barrier layer, protecting the substrate from the environment and vice versa. They are provide an excellent moisture, chemical, and dielectric barrier as well as being biocompatible and biostable, thermally stable, lightweight, low friction, and pinhole free.
Parylene coatings are used across a range of applications and substrates including catheters, stents, cardiac assist devices, bone pins, cannulae, implants, cochlear implants, medical electronics, electrosurgical tools and more.
Medical coatings manufacturers and suppliers in the UK
The medical coatings market is a varied one, with many companies providing a range of services. Top companies globally include Specialty Coating Systems, Royal DSM, Precision Coating Company, Sono-Tek, Harland Medical Systems, Coatings2Go, Biocoat, Bayer, PPG, and Covalon. In the UK coatings are available from Surface Technology (Armourcote fluoropolymers and dry film lubricants), Curtiss-Wright (parylene coatings), Accentus Medical (implant and antimicrobial coatings), Impreglon (antimicrobial and lubricant coatings), and many more.
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