WaterScope - preventing disease

A new 3D printed microscope could provide a low cost way to test for waterborne diseases.
27 September 2016

Interview with 

Dr Richard Bowman, The University of Cambridge


Contaminated drinking water is a major source of disease in poor countries. WaterScope disassembledThousands of children die every day from waterborne illnesses. Fortunately, Cambridge scientist Richard Bowman is working on a low-cost solution called "WaterScope" a hand-held plastic microscope that can test water samples for infectious disease.

Chris - Richard - how did this project get started?

Richard - Well, it got started about a year ago now, when a student project looking into how we can do water testing faster and more cheaply, came up with the idea of using a microscope to essentially shrink existing tests and do them much faster. What the microscope does is tell us whether particular water is clean or dirty. Normally you do this by collecting some water and incubating it overnight with some nutrients for the bacteria, then the following day you can see colonies of bacteria with the naked eye, and that's how you tell if the water's clean or dirty.

If we do the same experiment under a microscope, you can see the bacteria after more like an hour and so you can get an answer much more quickly.

Chris - Now that's very laudable but, of course, people in poor countries can't afford expensive, high-end microscopes which is, presumably, why you're going down the route you are?

Richard - Absolutely. We want to make the microscopes very cheap, very easy to use and, ideally, we want to be able to make them in the countries where they're needed to avoid having to ship stuff in from the UK, which is very expensive.

Chris - But, if you are making the case that a poor person can't afford an expensive microscope, can they afford an expensive 3D printer?

Richard - Well, we don't need every person that has to test their water to have a 3D printer, but we're starting to see labs setting up, where they do have 3D printers and they're looking at ways they can use these to produce useful products like, for example, our microscope.

Chris - So how do you 3D print a microscope and are they any good?

Richard - They actually work really, surprisingly well. The trick that we've used to make the microscope is quite an old one. Essentially we take the wide angle lens that you find on most webcams and turn it upside down, put it slightly further away from the camera sensor, and it becomes really quite a good little microscope objective.

The other ingredient is holding your sample in the right place and being able to focus it. And we do that by, essentially, instead of sliding stuff around, which is hard to do on roughly made 3D printed components, we use the flex in the plastic to actually bend the structure to move the sample into focus and move around on it.

Chris - That's very clever. So how do you actually build one of these things - just talk me through piece by piece - is it like airfix? You know those kits where you used to make little aeroplanes from pressing out the things - some of the them about the size of a proton from what I can tell(!) and assemble them into a working gadget.

Andrew - Yes, it is a bit like. The microscope prints in I think it's ten or eleven pieces, depending on exactly what you build. Most of it actually prints in a single piece so all of the sensitive flexure mechanism that handles focussing it and translating the sample comes off in a oner. Then you have to add in three screws, which is what you use to move the stage around and to focus the microscope, and snap in the camera and the optics. So the whole thing - well it takes me about twenty minutes-half an hour but I've built quite a lot of them now.

Chris - But even so - that's not long is it? And the proof is in the pudding though - does it work?  If you take a sample of dirty water from a puddle or a river and put it under the microscope - can you see whether or not there are germ-forming bacteria there?

Richard - Absolutely we can. We're still working on some of the sample collection stuff, so going from the dirty water to something on a microscope slide that we can image. But the imaging part works really well and the rest of it we hope to have sorted out in the next couple of months.

Chris - And once it is sorted out - how does it get deployed and where are you targeting?

Richard - In the first instance we'll do a few small trials with a couple of partners. Take it out to places where they're already doing water quality monitoring and test our system versus theirs. Once we've established that it's all working nicely, we would work with the same partners to start getting testing kits out with their aid workers so they're being used by someone that will feed back to us how they're working and how we can make them better.

Chris - And, can you also effectively establish a surveillance network by having lots of these on the ground in lots of countries afflicted by waterborne illness problems, does this give you data that you can then share in order to anticipate need for healthcare and also tell people there's a problem coming - don't drink the water?

Richard - Yes, exactly. And one of the most powerful things about it is that it is all built around a computer - in this case a Raspberry Pi. So all the test results are digital and we can send them back and build a database and sort of map out where the problem is.


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