The market for medical devices is highly regulated, with long product-development cycles and extensive procedures for obtaining regulatory approval. These characteristics make it challenging for companies and research groups to translate laboratory innovations into clinical practice. The National Healthcare Photonics Centre – part of CPI (Centre for Process Innovation), and located in Sedgefield, UK – aims to ease this translation process by providing practical support for developers of light-based tools for diagnosing and treating disease. On the centre’s opening day in March 2019, I spoke with CPI’s healthcare photonics lead, Tom Harvey, about its plans.

What are some key emerging applications of photonics in healthcare?

In terms of commercial importance, and applications that are in the clinic today, CT scanning comes first. People don’t always consider X-rays part of photonics, but for us, they are. CT scanning is a comparatively mature technique in terms of the hardware designs, but there’s still a lot of work being done on analysing the images it produces, and especially on the use of artificial intelligence (AI) in image analysis. Radiography is probably the most advanced clinical area where AI is making a difference.

The next technique I’d mention is optical coherence tomography (OCT). The importance of OCT is not to be underestimated. It’s used in ophthalmology to inspect the back and the front of the eye, and recent developments are lengthening its depth of field in a way that is analogous to earlier advances in the history of microscopy. We started with normal, 2D microscopy, and now everything is in 3D, going deeper into tissue using longer wavelengths of light. The combination of OCT and other types of imaging is also very powerful, especially for inside-the-body imaging. You can catheterize the OCT instrument, place it inside the body, and combine that information with fluorescence imaging to look at, for example, both the walls of the artery and the tissue type. Or you might inspect the bowel for tumours by giving the patient a fluorescent molecule to consume that sticks to those parts of the intestine wall that are not normal tissue, then go in and look at that.

There are also some interesting developments around using different lasers and laser techniques for healthcare. Medical lasers occupy a growing market sector in their own right. These laser types, such as the holmium:YAG laser, are designed to operate at wavelengths where absorption due to water in tissue is high, so that tissue absorbs the laser energy and is ablated. But they’re relatively large and expensive, so innovation is focused on making more compact or lower-cost laser sources or extending the range of laser sources available at different wavelengths. That’s where devices such as quantum cascade lasers (for mid-infrared wavelengths) and techniques that convert laser frequencies either up or down are coming into their own. We’re also seeing improvements in the performance of so-called “white-light” or “supercontinuum” lasers that give you both laser power and tuneability in the wavelength.

On a related note, fibre lasers are also very important in medical applications, as it is possible to get both high power and high beam quality at wavelengths between 1–3 µm. Also, improved methods for delivering the laser light to the patient are being developed. This is something that’s being done at Heriot-Watt University, for example, in partnership with researchers at the University of Leeds, using ultra-short-pulse lasers for tissue resection in surgery. One of the advantages of having a short laser pulse is that you avoid heating effects, so you get a very clean scalpel cut without any cauterization or damage to the surrounding tissue.

Another big area for healthcare photonics is Raman imaging. Larger, research-based Raman microscope systems have been around for a while, but until recently it wasn’t possible to do Raman spectral imaging through a fibre, because you would excite too much Raman signal from the fibre itself. Now, thanks to new developments in hollow-core fibres, you can point the fibre at something in the body and say, “Because I see this marker present, or this tissue is producing a different type of Raman spectrum, therefore it must be in a diseased or abnormal state.” The technique has advanced massively, but there is still room for improvement. Because the cross-section for Raman scattering is so small, you get very few photons scattered, so you need very sensitive systems to detect them – especially if you’re trying to do the imaging in real time, so that you can use the Raman signal for guidance as to what tissue to cut away during an operation. Real-time Raman imaging will require improvements in the electronics and better optical signal processing.

So we’re seeing some themes emerging around diagnostic imaging and therapy, but honestly, I never really know what clients are going to want when they walk through the door.

How will CPI help transform laboratory devices into commercial products?

We have a range of assistance that we can provide. First, there needs to be an entity that wants to collaborate with us – usually a spin-out company or some other commercial entity that wants to take an idea forward, sometimes an academic research group. We’re not looking to develop products ourselves. We’re not a business; we’re an independent, not-for-profit organization, so it’s not us that drives the process. Instead, clients come to us, and we ask them what they need to turn their idea into a product. It may be that their concept is fine and so is their design, but they don’t know where all the parts are going to come from for the real product, or they don’t know what the best method is for assembling it. The idea is that we provide that support.

We can also do more in-depth things, such as examining clients’ optical design or working with them on developing the electronics they need to control their system, if they haven’t done that already. We can give advice on whether their device is operating within a regulated, quality-control system, and if it’s not, we can show them how to build a technical file, which is what they’ll need if they’re going to get CE marking [European regulatory approval] for their device. We can guide them through that process and help them collect the appropriate information.

We’re also applying for a licence from the Human Tissue Authority, which would permit us to collect human tissue samples, bring them to our labs and use them to make measurements with the prototype devices that people bring to us. In some cases, products have failed because their makers only had access to a limited number of tissue samples, whereas patients are hugely diverse. It’s one thing making a device work one time in the lab. It’s completely another thing demonstrating that it will work across the range of different patients: men, women, young people, old people, people with different stages of a disease and so on. Getting that robustness is important, and that is what CPI is interested in doing. We want to do the legwork to help companies get to the stage where they’re ready to launch their products onto the market.

What would make product or service development in this field easier?

Smaller companies really appreciate the total package – they need help with funding, they need access to facilities and experienced people, and they need to be introduced to the regulatory environment. They may also need more than one part of CPI to help them. For example, we have groups devoted to biopharmaceuticals manufacturing, industrial biotechnology, printable electronics (including flexible and wearable electronics), and we have CPI’s capabilities for materials development. An example of such a project is one with some aspect of photonics in the product – a detector, for example, or a reader for an in vitro diagnostic device – but the company is also interested in is something else, such as the reagent they’re using or the antibody they’re developing that is specific to a particular condition or disease. Then we can bring in different parts of the organization to help them.

Larger companies, in contrast, usually have all the resources they need to do product development in photonics, but their people may be tied down with standard tasks, such that they don’t have the capacity do something a little bit different or disruptive. That’s the sort of thing that we can potentially work on with them. Somebody can come to our labs and carry out some measurements that are a bit unusual, on things that they wouldn’t normally do in the corporate lab.

Then there are companies in the middle. They might like to develop a new product line, but they don’t have the resource to do that, so they can pay our staff to work on it. For example, companies making spectrometers may not have good applications notes for the full range of possible medical applications. So if we develop those applications notes, that can really add value for them.

You’re a physicist by training. How do you see physicists contributing to the field of healthcare photonics? What do they bring that an engineer or a bioscientist wouldn’t?

I work with people from a lot of different disciplines, and I find that really stimulating. But photonics is definitely a physics thing for me. My PhD at Heriot-Watt was in the nonlinear optics of conducting polymer systems, so I’ve always been interested in the interaction of light with materials. I think as physicists, we bring an understanding of instrumentation and instrumentation systems design, but we also understand the basic science of what’s happening when we look at a sample. We understand things like refraction and light scattering and absorption and emission, and that understanding is helpful. It means that when I enter discussions with companies, I have a good grounding and understanding – most of the time! – in the basics of what they’re doing. I love engineering as well, and the crossover between physics and those other disciplines, but an understanding of the physical processes involved in photonics is key to the whole thing.

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