Resources | Full Spectrum LEDs | Jürgen Honold | Opinions | Nov 30, 2020

Tech-Talks BREGENZ with Jürgen HONOLD, Dipl.Des.(FH)

At LpS 2019, Jürgen Honold, Dipl.Des.(FH), and his co-presenter Dr. Martijn Dekker, held a very interesting and remarkable lecture about photobio-modulation (PBM). LED professional wanted to learn more and asked Jürgen Honold for an interview. As Technical Fellow, he is responsible for Seaboroughs' advanced lighting research and development and exactly the right person to talk with when it comes to HCL and related technologies and applications. Dr. Martijn Dekker, CEO of Seaborough accompanied him and gave an introduction with additional insights into Seaborough and the company's structure and strategy

LED professional: I'd like to welcome you both to the Tech Talks Bregenz. Thank you for taking the time to give this interview. Could we start by you telling us a little about the focus and activities of Seaborough?

MARTIJN DEKKER: First of all, we'd like to thank you for giving us the opportunity to talk about Seaborough and the exciting project that we presented here in Bregenz. Without a doubt, the LpS is the leading conference in Europe, and we were happy to be a part of it.

The company was founded in 2013. From the outset, the company focused on breakthrough inventions for LED lighting. Breakthrough – because it's private equity funded so the results must really have a significant level to justify the risk profile of a company like ours. Over the years we have worked on many different subjects. In the last two to three years we have pruned the portfolio and focused basically on three key topics that are driven by the competencies in the company. In the end, it's the people that make it happen. Those competencies are electronics, material science, and light and health in combination with system design.

In electronics we have a truly retrofit solution for tubes. A ban is to be expected there very soon and the market will have a significant pool – and we have the only product with a proven compatibility of very close to 100%.
The second project is about narrow band red phosphors with close cooperation with many institutes in Europe – especially Germany and France. The third and probably most important topic that we work on today is on healthy light. – It was also the topic of our lecture in Bregenz.

The team is about 15 – 20 people who are based in a building in the science park in Amsterdam in the midst of the vibrant, vivid and entrepreneurial and science-oriented environment.

LED professional: As far as I know, you started with technology driven topics. The first two fields you mentioned, just now. Then there was a switch from technology to life science, human centric lighting, and applications. How did this come about?

JÜRGEN HONOLD: In my role as Technical Fellow I was responsible for filling our innovation funnel with new initiatives. After I looked for new topics and explored the field of light for health and well-being - an activity that I started in early 2016 - we first tried to develop some up-converted phosphors for healthcare applications and phototherapies. During this first project we got in touch with the photo-bio-chemical interaction of tissue and light for the first time; a scientific field which isn't very common or well noted in the general lighting industry. And during that project we became aware of other photo-bio-chemical interactions, which is what we are focusing on now – photobiomodulation in general lighting.

LED professional: You said that there are 15-20 people working at Seaborough – so it's quite a small company. When you do a lot of research you need a lot of capacity and I read on your home page that you work together with universities and research centers. Can you tell us a bit about your research network?

MARTIJN DEKKER: We have a strong link to the research group of prof. Andries Meijerink at Utrecht University, one of the best-known professors in the area on the subject of up-and down-converter materials. We also worked together with the university of Groningen on the specific up-conversion project to develop dye-antennas and then we have a Eurostars project funded by the EU that started in November, 2018. There we work together with Fraunhofer IAP, the center for applied nanotechnology, CAN, in Hamburg, FGK in Hoer-Grenzhausen close to Koblenz and a company called MJR Pharmjet near Saar Louis. When you look at the electronics, there we team up with large ODM companies in China. It's the main manufacturing base for our industry. And very specifically, we have Sengled, the number 5 ODM in China. And then there's Opple the number one lighting brand in China and a very aggressively growing brand in Europe. These are in the public domain, as partners. Next to that, we have discussions with many other well-known companies that we sometimes can disclose and sometimes cannot disclose because of an NDA.

LED professional: When I think about the three topics you are working on, I also think about "creating value" by using synergies: Today's LEDs aren't very efficient in the long wavelength range because phosphors aren't very effective in this range. You deal with phosphor development, as well. Wouldn't that build a bridge from one field of activities to the other?

MARTIJN DEKKER: This actually happened during the conference! One of the LED manufacturers asked the same question. So we're thinking of doing it indirectly. The material systems for efficient narrow-band red that we work on can be applied to many wavelengths, so a crossover is absolutely conceivable. But so far, that has only happened in my thoughts. At this stage, I don't think I could sell that to my shareholders. It could be a way for the programs to reinforce each other, but right now it's not our focus.

LED professional: In this case, as you presented a lecture about photobio-modulation that caught not just our attention, may I now switch directly to what you talked about yesterday? Can you explain to our readers what photobio-modulation is?

JÜRGEN HONOLD: Sometimes it is also helpful to start by understanding what it is not; so let me start by saying this: It has nothing to do with the effect of heat on the body. It is also not about the eye exclusively – because that's what the lighting industry have been focusing on, so far. Our understanding of light needs to be amended with the interactions of light with the whole body – with every cell in the body that can be reached by certain light intensities.

Photobiomodulation causes certain beneficial local effects, and subsequently systemic effects that improve health and well-being. You could say it causes a full body maintenance. It very likely causes many of the beneficial effects everyone expects and experiences when going out in the sun. Photobiomodulation is a scientific field that can explain, to a certain extent, why we feel good or why we regenerate in sunlight. This is obviously very interesting since we can aim for getting the benefits of sunlight into human centric lighting. If fully understood and transferred into general lighting we may achieve very similar effects – something that we haven't achieved, so far.

Our definition of photobiomodulation, if you look for a very short definition, is stimulation, regeneration and protection of tissue via photobiochemical interactions. It does this mainly with the red and the infrared light spectrum. And at the core of what it really does, is that it boosts the mitochondria of the cells, it improves cell metabolism. This is such a fundamental effect, which triggers a cascade of other effects, that it`s very likely that photobiomodulation is beneficial for many health issues of our everyday life: For example, diseases of aging or chronic diseases. There is a lot of research about this. In the past 10 years, many activities in the medical field found support for this thesis and show a clear, positive effect of photobiomodulation on humans.

To explain this in more detail, we need to understand that this happens at a cellular level: There are certain chromophores in the tissue, for example, the so-called cytochrome c oxidase, a terminal enzyme in the breathing chain of the mitochondria. It's assumed that this is the key chromophore that absorbs the red and NIR light. Much more is known to science already and when you talk to the active researchers in the field, they are looking to the left and right already to see what else might be happening by the complex interactions of tissue with light, for example, using other wavelengths which interact with other chromophores. To wrap this up, just imagine that life has evolved in sunlight more than a billion years, and we have just started to understand the complex interactions of living cells and light.

Figure 1: Cells, mitochondria & breathing chainFigure 1: Cells, mitochondria & breathing chain

LED professional: To understand the overall picture better, let us take one step back and look at lighting, in general. Most lighting is made for humans and what is interesting to me is the fact that if we take this into account – every light should be human centric. But what do you consider to be human centric lighting – when does light become human centric?

JÜRGEN HONOLD: Exactly how the old definition defines human centric lighting. When you look it up you see that human centric light is defined as lighting that supports performance, health and well-being by means of the emotional, visual and photobiological effects of light. The common definition already encompasses the photobiological effects. But so far, we've only been looking at what is happening in the eye - also regarding the non-visible aspects of the light. So, the definition is right but the "tool-box" needs to be extended so that we`re able to achieve something similar to sunlight with artificial lights. And this new tool is photobiomodulation.

LED professional: When talking about Human Centric Lighting in regards to health and well-being, the focus seems to be on melatonin suppression. We know that melatonin suppression is strongly related to short wavelength light. Your approach leans more towards the long wavelength light. Is this a contradiction or should light contain both?

JÜRGEN HONOLD: Certainly both. We don't say that the current scientific views or assumptions are incorrect when it comes to melatonin suppression, and so on - and how it influences our health and well-being via the optical track. This is a complementary part. It has other effects that are just not factored in, yet. But if you observe certain effects and you only focus on the optical track, how can you be sure that the effects that you see in the research is not also partly influenced by the chromophores in the tissue? The current view is too narrow and needs to be widened. I think that in the future, we will see research factoring in all of these different pathways. Not only the eyes, but also the tissues and the related systemic effects, and there will be a holistic view on the whole topic. Only that will give you an insight into what is really going on because then you have an extended view and you can see all the causes and understand the effects that you observe.

LED professional: In the 66th issue of the LED professional Review we had an article that was similar to the subject of your lecture, also about introducing infrared light to a lighting system. I appreciated the fact that you didn't talk about "unhealthy" light in your lecture, but instead emphasized that the light does what it should do while it could or should be improved. Something that I miss in this discussion is the production of vitamin D by UV light. How far would you go? What else should be included?

MARTIJN DEKKER: While Jürgen would have a very sound scientific answer to this, I'd like to answer it from my perspective. A start-up company needs to do one thing first: Focus! We believe that there are very interesting things that we are now trying to get the full value chain to engage upon with us. This is complicated and challenging enough and you need to pretty well look at it as building blocks. We have singled out that building block and that's where we want to make an impact. Especially as a small company you need to do it this way and step by step.

JÜRGEN HONOLD: Without going into a scientific explanation – when we looked at that topic, it was clear that – of course you can add UV – but in the end, if you have a lack of vitamin D, there are many supplements on the market. The ice is very thin in this field if you want to build a business case. It's completely different if you go to PBM. It's very strong. When it comes to the science of PBM, there isn't any supplement yet that can do what PBM can do. I think adding PBM to general lighting is the only viable solution to achieve the effect that we want.

LED professional: You said that we have been looking at the visual segment for many years. And the opening of the pupil is only a few square millimeters in size. But if we look at photobiomodulation, the receptor is the entire area of the skin. On the other hand, about 90% of our skin is covered most of the time. So my question is: Are there areas of the skin that are more important? How big must the uncovered area be or can we reach the same effect by increasing the dose?

JÜRGEN HONOLD: If the question is if there is a relation between the radiated area and the effects that we talk about, the answer is both yes and no. So, while some effects seem to be dependent on the amount of radiated skin, like wound healing or skin rejuvenation, most of the important systemic effects, like some crucial blood modifications in the arteries and capillaries of the skin, and that's supported by scientific studies, can spread in the blood volume and therefore seem to be less dependent on the size of the radiated skin. This is what the early research of the scientific group around Samoilova et. al (1998) shows. We think, practically speaking, that ten percent of the body surface, which we have to deal with, should be enough for a decent effect. As this is supported, we think it's a viable approach and it indicates that we don't have to change the dosimetry because the systemic effects are already induced even if there is only a limited amount of exposed skin.

But to clarify: What we have is a possible hypothesis, a very likely hypothesis! We are having discussions here in Bregenz with various partners about moving into the next phase, in order to test the hypothesis in meaningful settings. The good thing is that the received feedback of leading experts in the field of PBM is unanimous that this hypothesis has a very good chance to be confirmed.

We were basically running through open doors when we started sharing this hypothesis in professional circles. The most important scientific network where these experts are connected is called WALT. It has an historic background as World Association for Laser Therapy. Fifty years ago, it all started by using red laser light, but today many of the PBM experts use LEDs, too.

When we shared our approach and thesis with the leading authorities of applied PBM and also the leading authorities in PBM research, the feedback was strong: They literally said that this is very likely the biggest application field for photobiomodulation out there in the future. At this moment we are discussing with some leading experts what we need to test and how to test it, where to test it and who will be involved. These activities are ongoing, and the first tests will be up and running very soon.

LED professional: So that means that the effect is known, it has been proven and there is no big discussion about it. You also said that 10% of the skin should be sufficient for this effect, but for instance, how long would we need to sit here in our everyday clothes for it to have the desired effect?

JÜRGEN HONOLD: Our calculated dosimetry can be customized for different application fields. For example, if you are in an office environment, the dosimetry needs to be adjusted to enable a sufficient PBM dose during a common working day. However, these are calculations extrapolated from scientific studies, and we have to be very careful when applying this knowledge towards new application fields! We have scientific evidence based on clinical studies where PBM is applied as a therapy on various medical indications. Now, this is applied with a common technology that is different from ours for general lighting, and in a different context.

If we extrapolate what has been published in these 10,000 papers in this field and transfer the insights into general lighting – this is, of course, fact based on current research – we still need to verify it with tests because you have a different setting. Combined with general light, you apply it in a different way. You don't apply it with therapy lamps directly on the body – you apply it from a distance, you mix it with white light, and so on. How else would you do it in general lighting? While you know that we enable the same things that have been done in medical application research and you could assume that the result is the same, the circumstances are different. You cannot be 100% sure before having the answers on some important questions: One question is, does this different setting, combined with our novel way of applying the radiation, have an influence on the biological effects? Are these effects the same that are observed in research, in a lab environment or clinical setting? We need, at first, to have solid scientific evidence about this.

Let me also link this to some other thoughts discussed here at the conference to demonstrate what other questions might be relevant. As engineers and scientists, at least as technical engineers, we often underestimate the variations between people. We've been listening to that, and I think the personal aspects of the dosimetry is one of these elements you have to consider while you're testing.  

Figure 2: Equation for PBMFigure 2: Equation for PBM

LED professional: If you want to test the effect of PBM, what are the measurement variables? We know from melatonin suppression that we can measure it by the melatonin content in the blood or some people measure the body temperature and heart frequency rate.

JÜRGEN HONOLD: That's a very good question. We thought about this for a very long time. We have some things in mind and we have already contacted the right scientists to discuss the next steps.

On the one hand, one option is to test if something happened with the content of the body fluids, for example by measuring the pro- and anti-inflammatory cytokine levels. That's the content of the blood or saliva that shows the activity of the immune system. PBM induces an effect on the immune system, and the inflammatory state of the body can also be measured by the levels of cytokines.

On the other hand, you can make the so-called perception tests. You can see if a PBM application had an effect on the mood, cognitive skills, executive skills, or the awareness of the subject. - Were people, for example, sleepier? Or did the quality of their sleep improve? Did they recover faster after excessive sport? Are they better at certain cognitive tasks? Does their productivity increase?

There are also well-known tests that can be applied in combination with such perception tests to see if something is changing with regards to behavior and in the blood. This is the, so-to-speak, short-term feedback that you can measure.

We have also considered local tests, where you can basically test the state of the skin: We looked at the irradiated skin and observed something related to the first mechanism. So, if the skin is less stressed, you can irradiate it with UV or stress it in other ways – cigarette smoke, or what you have – there are several ways to introduce that. Then you apply the PBM therapy using our technology and you measure the state of the skin. In theory we should be able to find some indications that we have caused a beneficial local effect.

Altogether, the combination of these tests will give us fundamental insights about whether or not we have caused something.

However, there's still a lot we don't know in this field yet. We need to test everything, and it's a challenge. PBM is not like math: You have to collect a lot of indications and make a lot of tests to build your case. It's possible that we will discover things that we didn't expect.

LED professional: In your lecture you mentioned that there was about 5% added energy needed to provide an effect. Is it a narrow band or a broad band that can induce these effects in humans?

JÜRGEN HONOLD: It's quite broad, actually. It's not like you can use the whole spectrum – you need to cover certain bands between 600 to 950 nanometers. For example, we know that at around 720 to 750 nanometers practically nothing happens, so there is a gap. However, these chromophores absorb quite broadly and there's also some overlay. Anything above 950 nanometers, and especially above 1100 nanometers, is already a bit speculative. But this is just a limited view of what we know now. But that's what the designs are focused on so far, and where we have the most evidence and empiric research.

LED professional: So what you're saying at the current status is that 600 to 900 nanometers is the range with some smaller or broader gaps in-between.

JÜRGEN HONOLD: Yes, primarily cytochrome c oxidase in the breathing chain of the mitochondria. This chromophore has a known absorption range. However, often are just two distinct peaks considered but we use a more generalized approach. We factor in different published action spectra from empiric research and also clinical studies with slightly different wavelengths. So, you will find small differences in the published action spectra, but they are mostly in harmony. I think it has to do with the different cells which are used in these very specific scientific studies, and the single effects which are observed. When targeting the whole body, a less specific action spectrum is most likely the best way to go.

LED professional: The reason I asked was to understand which LEDs could be used as with a phosphor you usually have a broader spectrum and for an LED that is designed for infrared you often have a smaller spectrum.

JÜRGEN HONOLD: At this stage there is no reason to say that either one of the two is excluded.

For example, when you look at the IREDs, that's the abbreviation for infrared emitting diodes, they are designed to have a quite broad emission – around 100 nanometers. As there is no need to have a very narrow band, there's also no limitation in using these sources. However, it's not that straight forward how to drive the various sources available – that's our secret sauce.

LED professional: Another point that I would like to address before coming to the final round is the very interesting point that you explained that the dose of a 100-watt incandescent lamp was too low for an effect and now we have LED technology that will take us one step closer to better health and HCL.

JÜRGEN HONOLD: LEDs offer the versatility which is necessary to do this. Outside the regime of energy savings, there are very few examples that have been recognized by the general public where we have utilized the versatility of LED technology. This is now one of the future examples where we may bring real value to the end user and businesses, that could not have been done before the LED was there.

To come back to the incandescent Lamp, it's an integral system architecture that can only be driven in one simple modus, and of course it can be dimmed. 95% of the energy is converted into heat and simple infrared radiation, which means that the required energy would be available to enable a PBM effect, but the dose, as supplied by the lamp, has no effect. It also can't be driven in a smart way to have such an effect.

With LEDs, we just need to add less than 5% of infrared to the visible light, but this tiny amount of energy is enough to enable PBM since we can customize and drive LEDs in a smart way.

LED professional: I think we've broadly covered the topic of the PBM. Are there any other topics that could pop up in SSL in the future that would be interesting to you? Or, since you're a small company and you're already working in these three fields, will you just stay focused on those topics?

JÜRGEN HONOLD: Within light and health, we will definitely stay with PBM because this is a new topic with so many possible applications. It will keep us busy for the next ten years, at least. There are so many enabling technologies we need to develop on all system levels, and we are also looking for partners to help make it happen. There is still a lot to do in order to introduce PBM to the market.

Figure 1: Office test lamp with PBMFigure 3: Office test lamp with PBM

LED professional: So it's really a mid to long-term project.

JÜRGEN HONOLD: Yes, for sure.

MARTIJN DEKKER: Yes, it is and this week has been very important and instrumental in conveying the message to our shareholders that we are indeed onto something exciting. And it's important that all the parties recognize the potential. And with that done, I'm positive that we will be put in the position to make it happen. When it comes to the other programs, the situation might be different. If there had been something of the same caliber, cooking, we probably wouldn't have mentioned it here, but on the other hand, it doesn't happen often that you come across a topic so interesting, with so much potential, as the one we came across during the last one and half years.

LED professional: In closing I'd like to say that it seems like you have opened up a new topic for general lighting and we are curious to see what you develop over the course of the next year. Thank you very much.


Jürgen HONOLD, Dipl.Des.(FH):

Jürgen has worked at Technical Fellow Seaboroughs advanced lighting research and development since 2013, and founded Seaborough Life Science, a Seaborough subsidiary with the focus on light and health in 2016. With an entrepreneurial focus and interdisciplinary approach he detected several fields of interest where he started research, such as luminescent materials and advanced designs and systems. A renowned developer of lighting concepts, electronics researcher, and award winning designer, Jürgen has lived for the vision of bringing LED light to life since 1999, adding numerous inventions to his name since (Nimbus Group, LEDO, Sillicon Hill & Seaborough). In his current position as Program Director of Seaborough Life Science (2019) he focuses fully on HCL, specifically on integrating photobiomodulation into General Lighting.