Fraud-preventing holograms

Science doesn't stay in the lab forever - a lot of it ends up being spun out into technology companies. Chris Lowe has created many of these companies, and joined Chris Smith on the punt to discuss a few of his spinout companies.

Chris L - I’m on my twelfth one now.

Chris S - What do they all do?

Chris L - They’re in various sectors. My research area has been healthcare by technology in general so that covers both diagnostics and therapeutics so the companies span that thing. We have one company working exclusively in the area of diabetes. We have others that are looking at other types of therapeutic modes. Others are in diagnostics area and so forth.

Chris S - I did read somewhere that haven’t you got a contact lens that monitors blood sugar for diabetics?

克里斯·L -是的。我们在世界第一组d to actually test it with a real person. We gave that person 180 grams of glucose, which is the standard glucose tolerance test, and then we monitored both the blood glucose and tear fluid glucose, which is where the contact lens comes in, and we demonstrated there was a correlation between the two. We’ve only ever done it with one person and that was published in 2006 and nobody’s ever done it since.

Chris S - What does the contact lens do and how does it signal to the person what their blood sugar is?

Chris L - Well, you’re well aware of a soft contact lens presumably - a daily wear contact lens. That’s made out of a polymeric material, and what we do is we incorporate into that a volume hologram. Now a volume hologram is not like the one you find on a credit card, which is a surface relief one. With a volume hologram we can produce layers of metal particles or layers of polymer which create a diffraction grating, so when you put white light in it only releases a single wavelength back out of it, and therefore it looks a coloured one.

Now if we can change the spacing of those fringes within the hologram, within the grating, we can change the replay colour. So the idea is that we put the hologram into a smart polymer, which has a receptor for binding the glucose. That binds the glucose, you get a change in fringe spacing, and hence a change in wavelength that’s replayed out of the hologram. So, in other words, the hologram looks a different colour and we monitor that colour.

Chris S - So the diabetic would have some extra sugar in their blood, that would end up in the tears? That would then enter the contact lens and change the thickness or the size of this grating which would affect the way that the light that’s going through it bends and you’d end up with them seeing a colour, presumably?

Chris L - Yeah. The patient won’t see it because it’s in the eye don’t forget, so we’re using a mobile phone then to actually monitor the colour in the contact lens and then convert that mobile phone response into a concentration.

Chris S - So they know how much insulin to administer or not?

Chris L - Exactly, that’s the idea.

Chris S - Does it work?

Chris L - It works in principle. And I say, we have tried it with one person. But, of course, you’ve got to do major clinical trials on this because people’s lives depend on it so you’ve got to do a significant kind of trial which we’ve not done yet, but we plan to.

I did bring some of our sensors along with us if you’re interested.

Chris S - have you got some?

Chris L - I’ve got some in my pocket. This is one of our holographic systems we’ve been developing. It’s the same sort of hologram that we put into the contact lens but, you see, this is used for a slightly different thing, it’s an authentication sensor. So if you got an expensive piece of... I don’t know, you might have an expensive handbag for example. Not that you have.

Chris S - Oh I definitely have, Chris. I do have an expensive handbag, especially at weekends.

克里斯·L -如果这是一个起源nal one you could put a hologram like this on it. This is a breath activated one. In other words, it changes as you breathe on it. If you see it on there it has SH on there. Now that’s one of the companies I was involved in - smart Holograms. If I breathe on it… you see it’s got little...

Chris S - It’s gone green with little ticks.

Chris L - With little ticks on it, exactly. That’s changing one hologram for another.

Chris S - Go on then let the cat out of the bag, how does it work? Because all you did was you went sort of “huh”, and huffed a couple of breaths onto the red colour which says SH, it turned into a whole bunch of little arrows looking green.

Chris L - This actually has two holograms in it. One starts off in the ultraviolet and the other one starts off in the visible region. This first one which says SH on it, that’s in the visible region. Now what happens is when you breathe on it the moisture in your breath, which is water, actually expands the holograms slightly. One hologram moves then from the visible into the infrared so you don’t see it, and the one that’s hidden in the ultraviolet moves into the visible, so you get the replacement of one hologram for another.