Medical device coatings and surface treatments are thin layers of material applied or an alteration of surfaces to improve biocompatibility, reduce the risk of infection, or else functionalize them in some way to improve performance or aesthetics.

Surface treatments are necessary for various medical devices, implants, and equipment to improve device durability and patient safety. For example, hydrophilic coatings help to reduce friction, improve lubrication, and reduce risk of infection in catheters, stents, and intraocular lenses. Invasive surgical equipment must also have some type of antimicrobial coating to minimize the risk of infection.

Factors driving the medical coatings and surface treatment market include the rising prevalence of healthcare-associated infections (HAIs), growing use of minimally invasive surgical procedures, and high demand from the medical device industry. The rising demand for customized and multifunctional coatings and other surface treatments are expected to keep the market healthy, as well. Specialized companies providing these technologies and services will constantly be challenged to meet the demand when the medical device manufacturer decides to partner with them for their specific, often complex surface treatment requirements.

In order to further examine the sector, MPO spoke to a baker’s dozen of medical device surface treatment experts over the past few weeks:

• Luke Almeida, COO of New England Electropolishing.
• Michael Gianfrancesco, senior director of NPI engineering and technology at Precision Coating Company.
• Mark Gross, CEO of Formacoat.
• Dr. Robert (Bob) Hergenrother, VP of research, development, and innovation at Biocoat.
• Kyle Hedges, product manager at Applied Plastics.
• Kevin Hess, vice president at Surface Solutions Group (SSG).
• Mike Ingram, VP of engineering at Vela Technologies.
• Arjun Luthra, commercial director at BioInteractions.
• Colin McCracken, product portfolio manager, material business development—biomedical at Oerlikon Metco.
• Steve Neely, co-founder and chief technology officer at VSI Parylene.
• Kristin Taton, Ph.D., director of science and engineering at ISurTec.
• Matthew E. Thompson, business development manager, medical precision components at Oerlikon Balzers Coating USA.
• David Wayne, director of sales and marketing at Vapor Technologies Inc.

Sam Brusco: What medical device trends are driving surface treatment innovations? 

Luke Almeida: We have seen increasing demand for stainless steel component parts for surgical devices. Increasingly we see rapid growth in laser cut parts used in invasive surgeries requiring vascular access. Cleanliness requirements are paramount, and parts need to be free of laser dross from the cutting and manufacturing process. Additionally, we have seen a trend in finishes moving toward more matte and non-reflective give, the way devices are used by clinicians.

Michael Gianfrancesco: The year-over-year growth and advancements in surgical robotics continues to challenge the performance of surface functionality. To support the single port, minimally invasive nature of surgical robotics, products now require surface treatments that deliver multifaceted functionality versus conventional performance. The use of PTFE coating, which is known for its lubricity, release, and insulative properties may now be required to provide a very thin layer of PTFE, which offers a conductive finish instead of its typical insulative property.

Over the past few years, growing supply chain issues have caused OEMs and CMOs to evaluate their businesses to ensure stability and continuity of supply. This has cascaded to first and second tier suppliers as medical device OEMs want to partner with businesses able to help mitigate risk. EU changes to protocols around cleaning and sterilization of reusable surgical instruments has necessitated innovations in surface treatments as well. Global OEM and CMO manufacturers will want to partner with surface treatment providers that offer a single solution for both markets.

Mark Gross: We find more customers coming to us with unique devices and needs than we have seen in the past. Customers are requesting unusual shapes and uses—more than just catheters or guidewires needing lubricity enhancements. As a result, the kinds of coatings required are diverse.

Kyle Hedges: Raw material availability and supply chain delays are forcing medical device OEMs and contract manufacturers to look at their coating providers differently. They are now focused on looking for the best long-term coating partner who can provide them with reliable inventory and resources as well as adapt to the ever-changing environment and their product development needs.

Dr. Bob Hergenrother: The primary feedback received from customers is the desire to achieve further and faster distal access to the body to better treat the patient using atraumatic devices. We have seen that the newest devices require greater flexibility on the distal end and to meet this requirement, we have been coating the catheter’s inner and outer diameter. Coating in this format allows us to reduce friction and assist the catheter in reaching its destination. We have also found the coating of the inner diameter (ID) has been an alternative to the use of PTFE liners. Due to the recent lack of supply for PTFE liners, we have been working with many progressive companies to help solve this problem.

Kevin Hess: Designers, research and development (R&D) teams, and engineers have traditionally been the driving force behind the development of functional coatings in the medical device market. However, recent changes in REACH and RoHS regulations have led to an increased involvement of regulatory teams in the design process, particularly for devices in later stages of development or commercialization. These teams are in search of functional coatings that are compliant with existing regulations and will have a life cycle greater than the product itself.

Mike Ingram: Many medical devices require assembly using adhesives and hydrophilic coatings to ensure proper function. Both production processes are moving toward UV curing of the adhesive or coating. Traditional UV curing processes offer little process control and are labor intensive with little ability to scale in production. Medical device companies are expanding their product portfolios, which necessitates equipment suppliers to develop versatile and adaptable platforms that can address the wider range of products and increase production throughput while improving quality. Lastly, medical device companies aim to lower costs and minimize scrap. They depend heavily on equipment suppliers to account for process variables and ensure process repeatability to instill confidence in their UV curing process. Our MiniCure3D and VelaCure3D curing solutions addresses all of these challenges.

Arjun Luthra: The importance of using coatings for prevention and protection of medical devices against infections is growing as the number of healthcare-associated infections (HAIs) rises. Researchers have been able to pinpoint some causes of hospital-acquired infections but there’s still a need to protect complex surfaces, including implants, from device-related infections as well as surgical equipment and other invasive instruments to be protected from germs and microbes. Protection of all surfaces in healthcare is critical to evolving the infection prevention infrastructure for patients, professionals, and visitors. The specific need for medical device coatings is almost universal, with increasing demand for implantable devices to be included within the evolving infection prevention infrastructure. Medical implants protected with a non-leaching antimicrobial coating reduces the risk of device-related infections and improves the longevity of the implanted device, in turn improving the well-being for patients.

Colin McCracken: From the thermal spray side, we are focusing on thicker and rougher thermal spray (TS) coatings.

Steve Neely: The need to enable similar, or even greater, device functionality into physically smaller spaces is a leading trend for innovations in surface treatments for medical devices.

This trend toward device miniaturization is driven by strong marketplace demand from patients and healthcare companies desiring less invasive medical procedures that minimize patient trauma and reduce cost. Miniaturization has not only positively impacted the very small, it has also increased the quality and effectiveness of other medical devices including handheld and mobile imaging systems, surgical robotics, and in-vitro diagnostics. As a result, innovations in surface treatments focus on maximizing performance in smaller form factor devices without compromising safety or reliability.

Kristin Taton, Ph.D.: As minimally invasive devices are being rapidly designed and manufactured to accomplish more complex procedures, surface treatment innovations need to expand beyond traditional hydrophilic coatings. Surface treatment innovations will increasingly be tailored to the specific device properties and needs. For instance, many advanced medical devices have multiple components made from different materials that need a coating to adhere to the various substrates while also maintaining ease of application. These devices would benefit from coatings that both ease insertion and better control biological interactions of the device surface with the body by reducing adherence of proteins and tissues, mineral deposition, clotting, or cloaking the device from the immune system or from bacteria.

Matthew E. Thompson: Surface treatment covers a broad stroke of deposition technologies and materials. Looking at our core technologies, there are two trends with the most influence on PVD and PaCVD coatings. First, growth in minimally invasive surgeries, and second, a growing desire to actively fight surgical site infections.

David Wayne: Physical vapor deposition (PVD) coatings are more commonly specified on medical devices to improve durability and function, or provide visual differentiation. Historically, application of these coatings has been outsourced to service providers. In the last several years, companies have shown particular interest in bringing this coating capability in-house to improve quality, reduce per-part cost, coat larger parts, and eliminate long lead times.

Sam Brusco: How is your business responding to these trends? 

Almeida: We have developed a proprietary electropolishing process called ElectroMatte. This is a multi-step electropolishing procedure that cleans, deburrs, and passivates stainless steel parts and components while producing a non-reflective finish. Additional pre- and post-cleaning operations are used when needed to effectively remove dross and contamination from laser cut components and tubing.

Gianfrancesco: Our engineering teams work with design engineers to understand their product application, expected functional performance, and think creatively to develop a solution that supports both product functionality and ease of coating application. We do this by leveraging over 40 years of industry experience and technical expertise to solve problems that previously hindered the development of medical devices.

To help alleviate some supply chain risk we continue to invest in our facilities, like our state-of-the-art fluoropolymer coating facility in the Coyol free zone in Costa Rica. We can provide the latest coating solutions while simultaneously improving logistics costs, turn times, and yields by offering local solutions to some of the largest OEM and CMO manufacturers in the industry. We are actively doubling capacity in our Costa Rica facility so we can continue to support the industry.

We have also developed and invested in a patented anodic coating process, known as MICRALOX, for aluminum alloys. Our MICRALOX process creates a micro-crystalline structure that can withstand a high pH, alkaline solution. MICRALOX is a single solution for protecting reusable aluminum surgical devices.

Gross: I hesitate to call what we’re seeing as a macro trend, for our reputation of taking on odd and unique projects is growing and we are comfortable with that. We continue to grow our roll coating capabilities with more capacity and breadth of materials that we can coat on and with. We are assessing high-cost (and hopefully, high value) plasma deposition machines and methods for a variety of potential projects to help solve some of the unique problems customers come to us with.

Hedges: We focus on providing more than just a PTFE coating. As a PTFE coating partner, we provide solutions and support to help make our customers’ PTFE coating projects a success. We support them from concept to commercialization with products, tools, and resources designed to make their job easier. We understand the availability of inventory for both R&D and production is crucial. Raw material constraints and supply chain interruptions make it difficult to design and manufacture products quickly and efficiently. That is why we carry a wide range of materials both coated and uncoated to quickly adapt and support our customers. Our online store allows our customers to have rapid access to this inventory, which ships within 24 hours to support R&D projects.

We also work to support our customers when they have complex coating requirements or unique grind specifications with experienced engineering and customer support teams to ensure that they are completely satisfied with your products and solutions.

Dr. Hergenrother: To support customers currently in the development cycle, we support them in two ways. First, our in-house coating services business provides rapid turnaround time for customers who are delayed in development due to supply shortages. Once the devices are ready to be coated, we provide normal turnaround times of three weeks but can also offer as fast as 24-hour coating processing. Secondly, we have been educating customers about the benefits of using an inner diameter (ID) coating option. Our ID coating process offers performance as good as or exceeds the existing PTFE liners in use today. We have also been testing our HYDAK coating capabilities to ensure they meet the requirements of smaller and softer substrate materials used in the newest development projects.

Hess: Functional coatings manufacturers around the world are working to reformulate existing products to eliminate restricted chemicals or create new coatings that offer the same performance without the use of restricted chemicals. We have partnered with several functional coatings manufacturers to evaluate these new coatings for use in the medical device market. Our R&D department can trial these coatings and provide fast, reliable data for our partners’ R&D chemists to optimize their chemical formulations. This swift, iterative process between us and our partners has greatly accelerated functional coating development in an expeditious manner.

Ingram: We use a patented curing chamber with diffuse reflecting surfaces to surround devices in a three-dimensional “bath” of UV light. The result is extremely uniform exposure of the entirety of treated parts to the UV light, whether the parts are small areas bonding parts together or very long coatings on catheters and guidewires. All surfaces are exposed at the same time to the same controlled amount of UV energy, and that delivery of energy is monitored in real time. The result is unprecedented control of the curing process.

To maintain a validated minimum curing dose, traditional curing methods require frequent UV intensity measurements and the entire process relies on an unchanging geometrical relationship between the parts and UV sources. The most commonly used UV sources suffer from rapidly declining UV output over time, resulting in rapidly changing and uncontrolled process parameters. With our 3D exposure chambers, these drawbacks are eliminated. This has revolutionized process control and product quality while reducing production speed when curing adhesives and coatings on medical devices. Most adhesive cure applications work well with LED sources. Our MiniCure3D systems have integrated LED sources. This eliminates the external lamp commonly used, reducing capital and maintenance costs.

Hydrophilic coatings generally require UVC wavelengths to cure. Since LED technology is not yet available for such short wavelengths, mercury discharge lamps must be used.
Traditional methods use many such lamps, which have a severely limited lifetime. Our VelaCure3D systems require fewer lamps, so we can use a higher performing type of UV lamp technology. This technology provides up to 10 times longer life than traditional arc lamps, further improving process control and reducing maintenance costs and downtime.

Luthra: New developments are bringing to light state-of-the-art antimicrobial coatings, such as TridAnt, which offer a new way to combat infections more effectively, efficiently, and for longer periods of time. These coatings are proven to provide monoclonal protection, which kills a broad spectrum of gram-positive and gram-negative bacteria as well as enveloped and non-enveloped viruses, including E.Coli, MRSA, influenza, norovirus and SARS-Cov-2. TridAnt is being utilized for enhanced skin protection and to prevent pathogens on woven and non-woven fabrics, hard materials such as metals (stainless steel and nitinol), and polymers (polyamides, polycarbonates and polyurethanes).

The new antimicrobial technology is non-leaching and safe to use in all environments, even for Class III implants implanted inside chronic areas of the body. Its active components target microbes (prokaryotic cells) and have reduced risk to human cells, unlike previous technologies. The coating prevents formation of biofilms for up to 365 days and is safe enough to protect skin for up to 48 hours without any noticeable reduction in efficacy. As a result, antimicrobial-coated medical devices are protected consistently with a highly effective and safe, non-leaching shield for their entire lifetime.

McCracken: For implantable medical devices, we will be introducing cascade TS gun coating technology that offers increased deposition efficiency and can operate for significantly longer between scheduled maintenance.

Neely: We are making ultra-thin parylene coatings more accessible than ever before. As medical device components become smaller and more complex, parylene coatings are uniquely suited to ensure dependable protection. That is because micron for micron, parylene coatings offer the highest level of protection available for medical devices.

Parylene is now accessible in two formats: traditional outsourced coating as a service or in-line production at a CM or OEM’s facility. Customers can now choose which coating production process best suits their needs. For customers who choose to bring parylene in-line, we offer a full parylene ecosystem that includes equipment, dimer, and parylene process development services so they can get started at their site quickly and confidently.

Dr. Taton: Research on new coating technologies is a vital and ongoing mission for us. Throughout our 17 years in business, we have prioritized and continued experimenting and inventing for the future. Our hydrophilic coating chemistry, ISurGlide, was designed to meet these expanding surface treatment expectations. This is possible because our core proprietary chemistry platform allows for durable adherence of a broad range of synthetic and biological materials to a device surface, as well as the ability to be further engineered for specific demands.

Thompson: In the area of minimally invasive surgery the instruments are becoming smaller and more complex for both traditional and robotic methods. These trends mean smaller instrument components are being asked to carry heavier loads, which can increase the risk of component failure. Through the use of thin-film coatings, such as diamond-like carbon (DLC), we can dramatically reduce friction and improve wear resistance. To meet growing needs, our company has dramatically expanded the range of DLC coatings to meet an array of niche needs. We have more than a dozen different types of DLC coatings (a-C:H, a-C:H:Me, ta-C, a-C, etc.) that allow us to provide a more tailored solution to a customer’s design/performance issue. In this way, coatings become a required design element to achieve performance goals and risk management targets. 

Methods to reduce surgical site infections and other categories of infection seem to be getting renewed interest. There have been a number of new technologies, including PVD coatings, helping to expand the tools available to fight infection. We offer both active anti-microbial PVD coatings, such as BALIMED ARGENTA (TiN-Ag) coatings, and many passive options. Our BALIMED ARGENTA will actively kill a wide range of microbes. We also have a large number of coatings that help create more easily cleanable surfaces. This can be especially useful in small, complex distal end effector assemblies.

Wayne: We have developed coatings optimized for medical devices, including orthopedic implants, guidewires, surgical tools and drills, and many others. These include titanium nitride (TiN), chromium nitride (CrN), diamond-like carbon (DLC), and zirconium-based PVD coatings in many colors. To simplify bringing PVD in-house, our team can provide detailed ROI estimates (throughput and cost), coat sample parts for testing, help with equipment selection (including pre-treatment), develop parts racking, provide training, and customize coatings for unique applications.

Sam Brusco: What near-future medical device innovations and trends do you foresee? How does your business plan to respond to them?

Dr. Hergenrother: We have been testing our coatings to ensure they are a match for the devices being designed and can achieve greater distal access. Our unique bi-laminar coating process enables us to meet a growing trend of companies using multiple durometer substrates across a single device. Using one coating formulation to coat all the device substrates is a definite advantage, and it simplifies the end solution without sacrificing performance. Finally, we have built a full-service coatings model specifically designed to support the unique needs of customers from discovery through development.

Hess: We see a trend in device manufacturers looking for functional coatings that meet or exceed all regulatory requirements. In particular, they are looking for functional coatings that are free of PFOA, PFOS, Hexavalent Chrome, and harsh solvents. To address these trends, we have worked closely with our partners and have developed a low-friction functional coating that is free of these restricted chemicals.

Luthra: Surface modification is a way of providing blood compatibility (hemocompatibility). We have developed Astute, an antithrombogenic coating which has been used successfully on chronic implants and on blood-contacting medical devices for over 25 years. Astute is a non-leaching coating that uses an active antithrombogenic component combined with additional passive components to mimic the natural endothelial layer. The active component gives the coating the ability to interrupt the blood cascade mechanism, preventing platelets from activating and hinders thrombus formation. The additional passive components prevent blood components from depositing on to the device surface. This multi-faceted approach provides superior hemocompatibility to the surface without any reduction in performance over long periods of implantation. 

The burgeoning development of miniaturized and minimally invasive procedures includes a variety of challenges like reducing the amount of tissue trauma by way of smaller incisions, and leads to potential reduction in infection risk, less pain, and more comfort during recovery. Addressing the dynamically increasing needs for smaller medical devices demands several key qualities from the components used to produce them. Size must be reduced without compromising quality and application-specific qualities that improve the functionality must be reliable.

We have sought to meet this challenge by developing a hydrophilic coating that is lubricious and flexible resulting in reducing friction, and has no particulate formation and delamination in high-stress and high-movement applications. Assist uses a two-factor approach to reduce friction at the device-body interface for long periods of time, hindering device occlusion and allowing it to remain in position for extensive use. This significantly reduces tissue damage and improves comfort when delivering or removing devices from the patient.

Neely: The trend I see gaining greater momentum is the move toward quicker development cycles. Medical devices have historically had long lifespans and development cycles.

However, increased competition and a shift toward incorporating new digital technologies has put a premium on speed and innovation in the industry. We are continuously shifting our focus from simply delivering high-quality coatings to how we can organize our processes, products, and services to help medical device companies compete in this new environment. The parylene equipment subscription service was born out of this desire to help simplify parylene coatings so customers can access and enable their technologies faster.