Perspectives on New Materials, Part I
New developments in material technology are critical to innovations across all industries, including medical device technology. Therefore, it is crucial for designers to stay abreast of the most recent advances that could benefit their upcoming products. In this month's Perspectives, industry leaders share their opinions on which new materials are the most exciting to them.
What new material technologies are most exciting/interesting to you for use in medical device design/manufacturing?
Process Engineering Manager, Saes Memry Corp.
As medical device designs advance, new material technologies must emerge to meet their more challenging performance and size requirements. In some cases, miniaturizaton has been limited by the physical properties of the materials used to fabricate the devices. This trend towards device miniaturization, while maintaining or improving performance, has forced the industry to develop new materials.
The demand for a superelastic material with a higher stiffness than the standard binary Nitinol has led Saes Memry to develop a ternary nickel-titanium-cobolt (NiTiCo) alloy. This alloy maintains all of the superelastic and shape memory properties of binary Nitinol with an over 40% greater modulus of elasticity. The greatly increased stiffness allows for medical devices with increased performance in a smaller device size. The smaller package size reduces introducer size and cost and also decreases patient trauma through allowing for smaller access incisions. Some typical devices that benefit from this cutting edge material include guidewires, embolitic protection devices, wireform stents, percutaneous heart valves, and PFO (patent foramen ovale) devices.
VP of Medical and Converting Technologies, Lohmann Technologies, G&L Precision Die Cutting
As an adhesive material specialist and coater for medical device applications, we must continually be in the lab customizing solutions that meet constantly changing needs. With design engineers developing more technologically advanced and efficient devices, we are challenged to deliver cost-effective, pressure sensitive adhesive solutions that can be readily converted into finished components.
For example, new technology is driving the development and rapid growth of biosensor monitoring for point-of-care diagnostics. With this comes the necessity for highly customized tape and coated film solutions that go beyond traditional coating processes. Film thickness, coating tolerances, and bonding demands for new substrates are challenges that must be met. Examples include the development of heat-activated films and innovative pressure sensitive adhesives in clear and opaque formats.
In addition, supplying these materials for the biosensor market is not enough. Adhesive solution specialists must work closely with converters to integrate their areas of expertise to ensure proper handling of pressure sensitive adhesive materials for laminating and die cutting in order to generate higher yields of components. As diagnostic technology becomes more advanced, it is imperative that coaters and converters work together to offer complete, seamless solutions from the polymerization of raw adhesives to coating of customer-specified substrates to precision converting, assembly, and packaging for this growing medical device market.
Product Director, Healthcare Materials, NuSil Technology
The surface of cured silicones is often characterized by a high coefficient of friction (CoF), some degree of tackiness, and a tendency for blocking (sticking to itself by virtue of chemical affinity). All of these inherent features may be problematic for applications requiring a molded or extruded silicone part to move or slide with minimal friction. A low CoF silicone coating was specifically designed to coat molded or extruded silicone parts to help overcome these obstacles. When applied with the recommended thin coat, it will cure rapidly with elevated temperatures, chemically bond to the silicone elastomer substrate and mimic the mechanical properties thereof. The result is a durable yet flexible coating that resists abrasion from moving, sliding, and rubbing parts. It achieves this with a smooth finish that may also result in a minimum 50% decrease in CoF when compared to non-coated samples.
By bonding to the substrate and resisting abrasion, the coating eliminates the concern of migration, commonly associated with lubricants such as fluids or greases. Potential end uses for the coating are: tubing (ID/OD), balloons, valves, stoppers, o-rings, and anywhere that you have moving or sliding parts.
Thermal management technologies are a very exciting part of medical device design, as moving heat away from sensitive electronic components and ensuring reliability have emerged as key challenges. Thermal management is steadily becoming more difficult because electronics are growing in power, processing speed, and complexity, while shrinking in size. This increases thermal density and limits space for cooling solutions.
VP, Engineering & Technology, k Technology
Traditionally, designers have favored passive heat transfer devices like heat sinks or heat pipes, generally made from aluminum and copper. In some instances, even silver heat sinks are used. But aluminum has limited conductivity, copper is relatively heavy (three times as heavy as aluminum), and silver, while very conductive, is expensive.
The latest thermal management approach involves heat spreaders made from annealed pyrolytic graphite, or APG. This material offers three times the conductivity of silver and is low density (30% lower than aluminum). APG is ideal for fast-cycling devices, such as gene splicers, allowing heat spreaders to respond immediately to temperature shifts of 50°C and more. APG is also an inert material that can be encased in a metal shell for added safety. All in all, APG-based thermal solutions promise to extend the existing benefits of passive thermal technology (reliability, operation in any orientation) in upcoming generations of medical devices.
Steel will always be an important material in medical device design, but recent advancements in polyethylene technology have supported the emergence of medical grade, ultra high molecular weight polyethylene (UHMWPE) fibers that offer significant advantages over steel in bending flexibility, fatigue failure, and specific strength and handling characteristics.
Business Development Manager, Medical, DSM Dyneema
UHMWPE fibers have presented device makers with a wealth of new design options, and opportunities to positively impact device performance, patient and surgeon comfort, and treatment outcomes. The fiber's outstanding strength relative to volume, for example, is supporting advancements in less invasive treatments and techniques. Its superior fatigue resistance has the potential to improve the performance and longevity of dynamic applications.
UHMWPE fibers are up to 15 times stronger than steel and enables medical device manufacturers to design smaller, lower profile implants for minimally invasive surgical procedures without sacrificing strength and durability. These fibers offer the most promising means for realizing the benefits associated with minimally invasive implants and techniques including shorter recuperation times and less scarring.
These are just a few of the reasons that growing numbers of device designers and engineers are turning to medical grade UHMWPE fibers to augment existing devices, innovate entirely new devices, and, most significant, improve the lives of patients and surgeons.
Plastics laser-sintering and direct metal laser-sintering (DMLS) systems, now as reliable as they are innovative, are about to transform medical engineering. These uniquely design-driven manufacturing processes are dramatically altering the design and manufacturing future of customizable, patient-specific devices.
Key Account Manager Medical, EOS
For example, Smith & Nephew uses plastics laser-sintering to create one-off, tailor-made, surgical cutting guides. DePuy Spine prototypes its custom instruments for spinal surgery in laser-sintered stainless steel and sees great potential for manufacturing. Other companies are investigating in DMLS for the creation of orthopedic implants. Just recently, Biomet Europe presented very positive results with laser-sintered CoCr for possible implant manufacturing. Another trend is to create porous titanium surfaces for better osteointegration, with mesh or scaffolding designs that will be far lighter and more comfortable than present ones, and in geometries impossible to produce by any other technology. EOS is also working in tandem with leading medical companies to validate the laser-sintering process as an accepted and mature technology.
Within the next few years, actual laser-sintered surgical instruments will be approved for use. Within five years, spine, knee, and other implants will be approved as well. These new, individualized products will bring extraordinary advances in patient care and comfort and change the way we think about medical design.