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MEMS and NEMS Make Headway in MedTech

While the MEMS and medical device worlds have very different engineering and design cultures, micromachining technologies are entering into medical device manufacturers’ calculations.

On Thursday, May 8, Chris Folk, principal engineer, device strategy at Thousand Oaks, CA–based Amgen Corp., will speak on “Advances in Breakthrough MEMS and Biomedical Nanotechnology” at MD&M Texas.” In the conversation below, he highlights a range of new technologies incorporating MEMS technologies and discusses some of the obstacles to expanding their use in medical device applications.

MDDI: In the medical device space, what are some of the latest applications incorporating microelectromechanical systems (MEMS) and nanoelectromechanical systems (NEMS) technologies?

Given Imaging's MEMS-based camera-in-a-pill technology is used to detect abnormalities in the bowel.

Folk: Both established and nascent medical device products incorporate MEMS and NEMS technologies. Products incorporating these technologies now include those used in the endovascular space. A good example is Volcano Corp., which produces a MEMS-based pressure sensor that is incorporated into a guidewire. This device is used to measure pressure within heart arteries. Guidewire technology has always focused on the device’s pushability and torqueability—in other words, how do you get to difficult-to-access places? To solve this problem, some companies work with magnetic fields to deflect guidewire tips. In contrast, Volcano Corp. and some of its competitors, such as St. Jude, extract information at the location of the guidewire. This functionality differs fundamentally from that of previous-generation guidewires, and it has a lot of value.

Other examples of medical device applications that incorporate MEMS technology include the camera-in-the-pill concept. Both Olympus and Given Imaging, which was acquired by Covidien for $860 million in December 2013, offer camera-in-a-pill technologies that are used to detect abnormalities in the bowel, such as gastrointestinal bleeding, Crohn’s disease, and anemia.

The needles in 3M's hMTS MEMS-based microneedle array measure from 500 to 900 µm in height.

More-nascent technologies incorporating MEMS devices include microneedles. While various forms of microneedles have been around for a long time, they haven’t been the subject of many commercial ventures. Now, however, a number of companies, such as Elcam, DebioTech, and 3M, are making a lot of advancements in the microneedle area, and some companies are beginning clinical trials. Initially, microneedle technology may be used to deliver vaccines, but it can be used in other applications as well. MEMS are also used to perform sensing functions, as in devices manufactured by Seventh Sense Biosystems.

Beyond these established and up-and-coming technologies is the whole wearables space. While not currently medical device applications, wearables are evolving quickly, and first-generation devices are already available.

Over the last few years, the price points of MEMS-based accelerometers and gyroscopes, which were largely driven by the iPhone, have been crashing. At the same time, their performance levels have continued to evolve. Thus, as the performance of accelerometers and gyroscopes at an acceptable price point continues to improve, the opportunities and the range of applications for wearables are going to bloom as well.

Today, people associate wearables with devices such as Fitness Tracker, not with technologies used for monitoring disease conditions. But in the future, wearable devices are going to be much more integrated technologies. Given the interesting regulatory space in which FDA has been given some guidance on the use of aps, wearable devices will increasingly incorporate wireless, micromachining, and sensor technologies over the course of the next five years. As a result, patients will be empowered into ‘virtuous cycles’ in which they will be able see objective, quantifiable metrics from their involvement in their own diseases and treatments. Ultimately, real-time, objective, quantified information will offer people the opportunity to change their behavior and may inspire hope for those facing tough diseases.

MDDI: What are the challenges facing medical device designers, engineers, and manufacturers in integrating MEMS and NEMS into medical devices?

Folk: There are certain bromides that people say about integrating these technologies into medical devices, but they’re still true. Most people in the MEMS and nano spaces are rooted in semiconductor manufacturing and favor bottom-up analysis, while medical device technologists are often more steeped in empirical techniques because of the complexity of the engineering physics involved. Medical device engineers often have expertise in such areas as optics or in such endovascular applications as stents and catheters—areas that are generally rooted in more traditional machining or fabrication techniques. If you look at what you can build, how you can build it, what materials you build it with, and the timelines for building things, there are some real discontinuities in expectations between the two communities. Thus, I’ve seen more than one business deal founder because the MEMS industry approaches business very differently from the medical device business.

Here’s a very simple example. If you’re making a micromachined device, you might approach a company that makes such devices. “Great,” they say. “We’ll do some designs, we’ll do some analyses. Perhaps this will take two or three weeks. We’ll prepare some photomasks. That’s about another week. And then we’ll go into the fab and make it.” When all is said and done, it could take perhaps a month to get through the queue, meaning something like a two-month lead time.

If you’re talking to an R&D manager or a director at a traditional medical device R&D startup, you’ll find that their tech people can often cobble something together in a day or two—a week tops. Thus, the idea of long lead times, meaning high investment costs upfront, is uncustomary in the medical device industry. And the pricing strategies between the two sectors are also very different. With micromachines, it’s very expensive to make the first item and very cheap to make 10,000 more, whereas with traditional medical devices, it’s very cheap to make the first item, but costs add up when you build up a line, ramp up from a pilot line to production, and go through process validation.

Sensimed AG has developed a pressure sensor based on MEMS technology for incorporation into contact lenses.

Some companies are solving these problems. In addition to Volcano and St. Jude, there’s Sensimed AG, which has developed a pressure sensor incorporated into a contact lens; Second Sight, which is developing implantable visual prosthetics for the blind; and Replenish Inc., which is producing a micromachine-based refillable implantable drug pump for the back of the eye. Nevertheless, there aren’t many examples of established medical device companies adopting MEMS and NEMS technologies and developing them in their own internal R&D centers. In fact, the growth of these technologies in the medical device industry is occurring largely through acquisitions.

MDDI: How do you think the gap between the traditional medical device and the micro- and nanomachining sectors can be bridged?

Folk: It’s really up to the MEMS community to demonstrate value to the medical device sphere. There are many examples of MEMS technologies that produce a beautiful picture, present a beautiful concept, or create a beautiful prototype and then fail. Particularly with wearables, MEMS technologies are beginning to creep into different avenues. As MEMS technologies develop more wins, traditional medical device firms, through acquisitions, will acquire these technologies and eventually develop their own internal capabilities.

MDDI: What about investment costs? Do high capital equipment costs discourage medical device companies’ from developing MEMS capabilities?

Folk: It would depend on the type of MEMS processes a company decides to bring in-house. MEMS processes include plating, lithography, reactive ion etch, and other technologies, the price points of which have fallen substantially—particularly at the feature size that is relevant for micromachining. However, micromachining involves a great deal of process development. For example, DebioTech has been working on its microneedle technology for close to a decade, if not more. High costs are therefore driven more by technology maturity than by capital equipment purchases.

The medical device companies that have enough money to make the kinds of investments necessary for succeeding in the MEMS space often make conservative choices. Or to put it another way, there are forces in large organizations that approach business, technical, or clinical risks conservatively. That’s probably one of the reasons why it has taken as long as it has for MEMS to cross over the medical device divide.

Bob Michaels is senior technical editor at UBM Canon.

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