Manu Prakash (Stanford): Foldscope: Origami Based Paper Microscopes

Manu Prakash (Stanford): Foldscope: Origami Based Paper Microscopes


Hello my name is Manu Prakash. I run a lab at Stanford and today I want to tell you about a new project in our lab that we call Foldscope, which is a completely functional microscope that you can make by folding paper. Let me tell you a little bit of the background about my lab. I work in the field of organismic biophysics, so I apply the ideas of soft condensed matter physics to the complexity and biodiversity that we see on our planet. We primarily work on basal metazoans, where we see all kinds of complexity in life forms that evolve on this planet. And, I’m just amazed by the microcosmos that exist on this planet that we just live and breathe every single day. But there are days where I’m actually jealous of my astronomy colleagues. And the reason I say that is that you can find a dark spot, and look up on the night sky and just with unaided eyes, try to comprehend the vastness of the universe that we live in. And every single person on this planet can have this experience very, very quickly. But if you wanted to do that for microscopy, or the microcosmos, it is an extremely difficult challenge. So, several years ago when I started my lab, I divided my attention to another field that we call frugal science, where the goal is to build scientific high end instruments that are available to every single person on this planet. We call this field frugal science primarily because the tools that we develop are trying to democratize the access of science to every single person. The inspiration for this started for me when I visited Ghandi’s Ashram, Sabarmati server years ago. It was quite an accidental visit that I stumbled upon this picture where Ghandi is essentially either looking at a slide for leprosy or malaria. I find this image fascinating, because in one single image, it captures how science and society connects together, and how you can actually use science to better humanity. One of the goals that microscopy is used for is field diagnostics, especially for infectious diseases. and the reason for that is that most infectious diseases have faces, whether it’s African sleeping sickness or Giardia or Leishmania or Malaria. They all have different forms that you can identify using microscopy. One of the other reasons that I am interested in the field of infectious diseases and global health is because I grew up in a developing country. And, for me, while growing up I felt that the need for scientific tools and the fact that as a kid, access to scientific tools were only available to a very few set of people. So, one of the goals and drives of this project is to try and change that, in a little bit. This is one of the images of how society felt several centuries ago, when for the very first time, they realized that there is a microcosmic life forms that all way to things that cause diseases to things that actually make us alive. Uh, here is a picture of monsters depicted in the cup soup of a British mom, a lithograph from the 1800s. One of the inspirations for our project was large scale manufacturing. So we looked at two different techniques. One, is the art of folding paper, which is called origami. Origami is fascinating, because it allows you to build complex structures with a single sheet of paper by primarily folding it. The other inspiration that we draw is from a visit that I had some time ago to a matchstick factory, where I learned that you can build billions of matchsticks and matchboxes in less than a month primarily using roll to roll manufacturing. We utilized both these techniques to manufacture a unique kind of microscope which we call Foldscope. So here is an image or CAD rendering of what the instrument looks like. I have the instrument right in my pocket. Here is an instrument that’s built primarily by folding a flat sheet of paper. All the optics and electronics are printed on this sheet, and then it’s folded together to make a fully functional instrument that costs us in part roughly around 1 dollar to make, and we can do imaging all the way from 700-800nm resolution. We can get magnification all the way from 140x to 2100x. One of the fascinating things about these instruments is the fact that it’s designed completely independently. It has a tiny slot for taking traditional glass slides. The way you use them is using two hands you move around for panning and the tension in your hand essentially changes your focusing. So to give you a view of what the complexity of this instrument looks like in such a simple form-factor. If I was to take this instrument and cut this in a side view, what you would see is several different components all the way from a light-emitting diode condenser lenses, several different apertures, the sample different optically lens configurations for different magnifications and all the mechanics that goes in into making a fully functional instrument. To give you a fair idea of what all the parts look like, here is a simple sketch. So what you’re looking at here is what we call a sample holding stage. Right here is the optics stage. And right at the bottom is an illumination stage. All the optics is printed into these tiny little modules which we use polymer optics or glass optics that’s printed in these little modules that can be inserted. Folding allows us to align these instruments directly into one single sheet, and once the instrument is put together these 3 different stages come together as a single unit. To just give you an example, here are the 3 different parts cut using a die-cutting process on a piece of paper Here is what we call as a sample holding stage, Here is the optics stage, with the optics module actually put in. And thirdly we have an illumination stage which has the light source, a watch battery, a switch, and an LED with a condenser lens on the other side. Each one of these stages folds and interweaves together to form an individual microscope that looks something like this. It takes maybe of the order of 2-3 minutes to fold this object in, and folding gives you a fully functional instrument. There is a tiny little slot right here, that allows you to put a glass slide so I’m just going to do a quick test to show you how to put the sample in. So, at this point the sample has been registered to the slide, and you can image it very directly to your eye either by looking right here, or essentially using this instrument in a projection mode where the image is projected outward. The way to use the instrument is by both your hands where you move your hands to change the field of view, and the tension in your hand gives you focusing. So just slight tension in my hand allows me to move my focal plane up and down to actually focus tightly on the sample that I care about. There is a lot of number of parts that go in to allow us the precision of this folding that I mention. And each one of these instruments is then manufactured using high throughput techniques. One of the fascinations that we have about microscopy is this idea, that why not build instruments with our own hands. And use them to see the microscopic world. We have done workshop with kids all the way from very young kids, for example right here, all the way to adults where the goal is to build instruments and learn how to make your own optical instruments before you utilize them. This is very similar to what is done in astronomy where people build their own telescopes. It takes 3-5 minutes to build instruments from each one of these parts. And to just simplify the process, we came up with a color scheme that allows you to fold these instruments primarily using color instructions. So it’s kind of like a game, you fold together parts based on how these colors come up on each other. There are no language or no other instructions that are required other than just following this color pattern. There are many different of instruments that you can make all the way from bright field, dark field, fluorescence, instruments that can do 2 micron resolution, polarization microscopes. It really depends on how you configure each one of these parts together. Here is a class of images that I took from one of the microscopes that I built a couple of months ago. There are lots of examples of images of diseases. Here is an example of E. coli, or bacillus, loa loa, malaria up on the top right there. But one of my favorite images is this of an ant leg which a kid while talking to her, asked me a question related to what is the strength in an ant. And there are typical answers that you would give, but what she was interested in was counting the total number of muscles that were there in this ant leg. And as you can see, what she identified are these striations of how these muscle structures are arranged in the leg of an ant. And yes, sure, maybe in the 1800s and 1900s somebody has figured out and documented this. But for her, it was a discovery of one. It was her curiosity that allowed her to ask that question, and using a very simple tool, get an understanding of her own. I’m going to now give you a quick demo of what we call a projection microscope, which is really designed for sharing images with a broader group of people. So I’m going to put in a simple screen right here, and just using the exact same instrument, right here with just a brighter battery, we’re able to project an image where a large group of people should be able to share and see these images live. What I’ve put in right here is just a simple squashed head of a fly, and you start seeing all these intricate structures. This is really the pump that allows flies to feed on sugar, right there. And then I’m going to move around to show you something right here, which is essentially a filter that’s built in, right on top of the flies head. It’s a bacterial filter. You can start seeing all these tiny little bristles which act as chemosensors. You can start seeing those tiny little holes in there, are essentially how flies breathe. And we move around to find the optics. Right here is the optical elements of the fly’s eye, which is a compound eye, and you can start seeing each one of these little holes, they act as essentially breathing tubes. Here is the neck, and you can see the entire surface is covered with these tiny, tiny holes, which allow flies to breathe just by diffusion of oxygen. So what’s fascinating about this projection instrument is multiple people can share images simultaneously and have a conversation about what they’re seeing in a live demo. One of the reasons that projection microscopes are very useful is the fact that it allows us to train microscopists out in the field on remote diagnostics. So, for field instruments it’s actually important for these instruments to be fairly rugged. We had a joke that we would throw these instruments and indeed they do survive several stories of a fall. They’re extremely rugged instruments and they’re truly designed for field conditions. So, I wanted to now end with where are we going. What is the vision that we care about? One of the visions that we have is of a world where every single kid could carry a microscope in their own pockets, at all times. This is very much like people carrying ball-point pens as a tool to write. We’ve been looking at this idea for the last couple of years, and sharing and building workshops for how to build these instruments, and explore the microcosmic world with everybody around you. And one of the factors that we have now identified is the idea of building a biology lab manual from the bottom up. We would like to recruit almost on the order of 10,000 users from all walks of life for a beta test, which essentially involves all the way from teachers, to kids, to organizations, citizen-scientists, to traditional scientists who are willing to essentially run experiments and share them with an instrument like this to a much broader community. I want to close this talk by acknowledging some of the funding sources that we have had, and point you to the website which has all the details for how to build these instruments, the technical details, and at the same time, a place to sign up if you want to be one of those beta users. Thank you so much for you time.

33 thoughts on “Manu Prakash (Stanford): Foldscope: Origami Based Paper Microscopes

  1. Achieving this kind of  magnification is no mean feat! Highly appreciable!! but does this thing available in India? Would want one for my son.

  2. Awesome, just awesome!
    Question thogh. If you were not chosen to participate into beta-test, where can I subscribe to more updates and finally a date of release?

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