40 Years of Medical Device Implants
There have been considerable changes in the medical device industry over the last 40 years, particularly in medical implants. As the NuSil brand of Avantor celebrates its 40th anniversary, we reflect on these changes and what they mean for the next 40 years. The company was born out of two especially demanding industries—medical implants and aerospace—and consequently developed highly specialized ultra-pure silicones and worked to translate application needs into fundamental silicone chemistry and processing.
We’ve seen five key developments in implants, which we explore below.
1. Innovation at any scale.
Innovation continues to be fueled at any scale, from entrepreneurs seeking to solve medical challenges to large multinational companies. Healthcare still needs novel solutions, whether it be through modifying current devices in the field or funding incubators or acquisitions. However, a greater degree of breakthrough innovations is coming from smaller, more agile companies. Meanwhile, the larger companies are seeking innovations that can help them meet the needs of their patients and differentiate them from their competitors.
A great example of this is in the cardiac pacing field. Pacemakers have evolved over decades to be smaller and smaller, with added functionality. Electrostimulation has expanded beyond cardiac therapies into neuromodulation applications. This has occurred both through the engineering improvements at the large multinationals as well as through innovative startups, some of which have been acquired by those same multinationals. Our commitment has served all levels of these innovators.
The regulatory landscape has also changed significantly over the last 40 years, and we've been involved in helping our customers make adjustments as needed to keep up with those changes. Historically, the innovation came first, and then we would test and meet all the regulatory needs. Now, that regulatory path is parallel to the innovation path.
2. From single- to multi-faceted property considerations, physical properties used to be the main concern when evaluating materials. Now, chemical properties and electronics compatibility must also be considered.
In the past, physical properties were the main facet of a material that was considered. For example, material properties such as durometer (or hardness) help demonstrate the cushioning or support provided by the silicone. Adhesive properties can be adjusted to enhance a bond or seal. As the applications grew, the processing parameters became critical to enable efficient production. Today, with the increasing complexity of device designs, applications require these specifications and more. Materials are now expected to serve multiple functions, such as providing both flexibility and electrical insulation, or adhesion, plus drug elution.
Often, we have to educate the designer on what silicone is capable of doing. I always try to stretch people's imaginations about the chemistry of silicone. Whatever people think it can do, it can do that and the opposite. For example, silicone can be a great adhesive and a great lubricant, and everything in between. It's how you bend the chemistry.
But that market evolution has brought some challenges. When silicone materials are only used for a specific physical property, there is some degree of freedom in the chemistry to hit that mark. You could get to a certain durometer or tensile strength, for example, by more than one route. As you add requirements, however, those degrees of freedom shrink. There's a solution, but the challenge to achieve is much greater.
3. Robotics are becoming more prevalent.
As medical devices get smaller and smaller, and more procedures are conducted in a minimally invasive manner or even robotically, tolerances become tighter. As a result, the need for lubrication is critical in two ways: either for the inner lumen of the cannula that you're inserting the device through or the outer surface of the device that is moving through it. These devices are articulated remotely, so all of the movement has to happen smoothly for the clinician.
4. Novel applications are evolving, such as silicones that are cured and molded in situ (inside the body).
As less-invasive surgery is becoming more mainstream, novel therapies are evolving.
Traditionally, long-term medical implants are preformed devices that require invasive implantation procedures. NuSil has a patented packaging technology that allows material to be sterilized in its uncured state. We’ve developed silicone solutions that enable the device to be formed in the body through much less-invasive means. So, rather than creating an orifice that's large enough for a product to be implanted through, the silicone can be delivered directly at the location where the device is needed and cured in the body.
As a result, therapies can be administered with a fit customized to the anatomy of the patient. Our silicone can also be customized to support the performance and process needs of the device. We expect this to be an important new development for cardiovascular, neurological, urological, ophthalmic, and aesthetic implant applications
5. Additive manufacturing applications are growing, including liquid additive manufacturing. These are not just for customized devices for specific patients, but also to eliminate the need for tooling.
I think 3D printing and additive manufacturing is an exciting new form of fabrication that is becoming more commercially available and acceptable. Three-dimensional printing with metals, thermoplastics, and different types of chemistries has been around for decades, and now 3D printing is possible with silicones.
The most obvious benefit is customization. We talk about personalized medicine and customized devices. I think this is where the next 40 years are headed in many regards, and 3D printing allows the device designer to deliver that.
Additive manufacturing is novel. Unique material properties are needed to meet processing and final property needs. We leverage our extensive regulatory experience to achieve these requirements for the medical device market. Knowing that designing a component from a new chemistry has a long road to regulatory approval, our formulation design starts with ingredients and processes with a known regulatory history. We properly document the use of proven processes and chemistry in master files that are on file with FDA to shorten that path to market for customers.
Three-dimensional printing through additive manufacturing opens a whole new realm of device design. Now you can form a complex, intricate part that was never an option with historic fabrication methods, and yet has all of the advantages and history of silicone. The possibilities become endless.
The process lends itself to a whole new world of automation as well. Now you can produce a device in real time and in unlimited number of shapes and sizes, rather than being limited by tooling or inventory constraints. Plus, consider the speed to market this creates, given the ability to take an idea to a CAD drawing and pressing a button to have a prototype “print” out. The ideas people bring to us will be things we've never seen before. That's the heart of the value of additive manufacturing. This is one of the biggest and most exciting opportunities we think this chemistry can offer to the life sciences marketplace. This is our next 40 years.