Archive for the ‘New materials’ Category

Have you ever longed for a magic dress that changes itself while you are wearing it? Well, someone has, because it is a trending topic in Ambient Intelligence.

Actually, color change is already solved (up to a point) and the answer is a substance known as thermochrome, that changes colors depending on the temperature. There are two blends of thermochromes: liquid crystals and leuco dyes. The first ones, you have probably seen in (cheap) thingies like mood rings or color changing mugs. Leuco dyes are a combination of colored chemicals that react when temperature goes over 25º C (approximately) and become colorless. The reaction is reversible, so when the temperature drops, they gain their color back. A layer of leuco dyes can be applied to any cloth and the resulting color is the combination of its original color and the substance … until it goes colorless. (Not so) Instant color change!

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Picture taken from Del Sol clothing

Of course, heat is kind of ok for a mug, because you can check whether the liquid inside is cold or hot, but not so much for clothes, because temperature tends to change too slow for changes to be too flashy. Other substances can be affected by different stimuli, like light, heat and friction. Lauren Bowker, from the Unseen, worked out a new ink (PHNX) that reacts to seven different parameters in the environment, including air pollution, heat, air friction and moisture. This basically means that your sweater could switch colors when you move from one part of the city to another. Chameleon style!

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Image taken from wired.co.uk

Cool, right? Well, you don’t have to pretend. I know that when we started talking about color changing fashion, you were thinking of this:

Well, maybe we can’t get exactly this (pity), but, is it actually possible to change textiles at will if we mix thermochromes and electronics. Take, for example, Chromosonic, by Hungarian designer Judit Eszter Karpati. She also relies on a temperature-sensitive dye, but instead of leaving changes to the whims of nature, she has actually woven nichrome wires into the fabric.

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Nichrome is a fairly well known alloy of nickel, chromium and other elements that has been widely used as industrial heater. If one heats up the wires in a pattern using, for example, a microcontroller, the dye in the surrounding textile changes colors responding to the pattern, which, in the case of Chromosomic, turns out to be an audio file. Problem is, obviously, that it’s actually way easier to heat things up that to cool them off.

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Image taken from Chromosomic (Tumblr)

… or, if you want to stick solely to electronics and make a dress that it’s not just a christmas tree, you can actually sew sensors and LEDs into your fabric and make it sensitive to whatever magnitude you want to measure. Environment Dress, from UH513, won the Next Things 2015 award doing exactly that. Only for the brave people, though!

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Ever wanted to grow your own TARDIS?

Breeding electronics is not a new idea in science fiction. Not only the Doctor’s most faithful companion is indeed a mix of organic and non-organic material that can be grown out of a piece of itself. Moya, in Farscape, is also a bio-mechanoid, in this case born from another Leviathan. And so are cylon raiders, from Galactica, the Shadows’ and Vorlons’ ships and the White Stars from Babylon 5. In Hyperion (1989), Dan Simmons also describes enormous tree-ships that are grown to move between the stars. And, actually, the trees in Cameron’s Avatar work like an enormous interconnected circuit.

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It’s no surprise, then, that people have been trying to grow, at least partially, their own circuits using bio-stuff. For example, Jean-Baptiste Labrune of Alcatel-Lucent Bell Labs came with the idea of Orgatronics, that combine transducers and microcontrollers with organic materials, mostly wood,

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Why would these circuits be interesting? First of all, you don’t build them, you grow them. They would be also way easier to recycle. Plus, according to their creators, they could use alternative power sources. Of course, we’ve got the sun, but let’s not forget that plants present potential differences that may provide some feeding to low power consumption electronics. For example, see how Texas MSP 430 microcontroller can be fed (up to a point) with almost any citric.

There have also been projects to feed conventional circuitry with, e.g. the potential difference created by tree root acidification, so, for example, trees could sense heat and trigger alarms in case of wildfires. However, electronics were conventional, even though they used the tree for power. It would be way better if the trees could grow just so, right?

This is, for example, the work of Andrew Adamatzky at the University of the West of England in Bristol. Based on studies about the electrical impedance of cucumbers and olive trees, he has focused on lettuce seedlings to create some sort of organic wire. The problem with organic stuff is that, unlike metals, it is typically not a good conductor for electricity. Adamatzky placed the seedlings across a 10 mm gap in a circuit, passed 1 uA current through it and measured impedance and potential over 10 minutes. Turns out his stuff behave like a 2.76 MOhms resistor, way higher than metals, but still well under the resistance of a body. He plans to use the seedlings to connect biosystems with silicon devices. The main challenge Adamatzky is facing is how to control the growth of the seedlings, which is in no way well structured. However, given that the resistance of materials change with factors like, for example, temperature, these thingies could be used to create fully organic sensors.

Still a long way to go, but moving in the right direction.

Source (partially): MIT Technology Review

One of the things I recall best from Mass Effect 2 is the awesome start video introducing Project Lazarus, where the main character is reconstructed from his/her charred remains after a fatal incident by a scientific team and awesome robotic equipment.

Whereas the Frankenstein approach to the problem looks a bit excessive even for scifi standards, we have seen similar scenes in many scenarios where the patient was still alive. It is easy to recall the bacta tanks in Star Wars, where people is submerged in a healing agent, but our focus today is Private Rico, from Starship Troopers, instead. Why? Because there is actually a robot regenerating the tissue of his leg to fix it. And because there is research in that direction nowadays.

It all starts with 3D printing (stereolithography), a concept invented by Chuck Hull  in the 80s, when he founded 3D Systems, Inc. 3D printing basically consists of designing an object with a CAD program and supplying it to the printer software to be sliced into thin planes. Then, the printer hardware recreates the object layer by layer by recreating each plane on top of the next using rubber, plastics, paper, metals and more. This is typically achieved by heating up the material and sending it as a filament to a extruder, that moves over the plane according to whatever shape the software wants to recreate.

So far, so good. If you are a hobbyist, you can actually purchase a basic 3D plastic printer for 400 USD (if you don’t mind to construct it yourself from the components). If you want something more complex or in a different material, there are many companies out there that will print it for you if you provide the CAD design. However, the real kick comes when someone starts to wonder how far 3D printing can be taken.

As was to be expected, someone already wondered what would happen if, instead of inorganic stuff, we fed the 3D printer with something organic. Obviously, the first design was a chocolate printer, but, shortly after, doctors and engineers started to think about the possibility of actually printing human tissue. And, believe it or not, there are even companies like Organovo engaged in this kind of product.

The living tissue 3D printing process involves 3 different research areas:

– First, it is necessary to determine which materials to use in order to print a given item. This process is far from easy and, in fact, may require molecular analysis to determine how it is formed.  Once the proper combination of living cells for the (piece of) organ to be printed are available, we are ready to feed them to the organic 3D printer.

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-Second, it is necessary to create the proper CAD models of the tissue to be printed. Realistic models are not that easy to come by. For example, the structure of bone has been recently decoded by MIT researchers and revealed to be a complex combination of collagen and mineral forms into a nano composite that creates a very tough, strong and reliable material (see image above). Needless to say, this information would become really handy for bone transplantation and orthopaedic surgery. The image below presents liver tissue as bioprinted by Organovo.

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– Finally, when the CAD model and the required cells are available, a special kind of 3D printer is needed. However, the technology below the bioprinter is very similar to your everyday plastic ones. According to Michael Renard (Organovo):

“Tissues are built layer by layer, using a combination of hydrogel and cell aggregates deposited in specific spatial arrangements that are programmed into the bioprinter. A wide variety of shapes and orientations can be created using the combination of these materials.

When you deposit cells they have to be the right cells and in the right biological state; the hydrogel holds them in the right place. Then the cells fuse, form junctions, and the hydrogel can be removed to yield a tangible piece of material made up entirely of human cells.”

It is not time to get our hopes too high yet. At the moment, they are growing small parts like a small piece of blood vessel or liver. Organovo expects results like nerve grafts, patches to assist a heart condition, blood vessel segments, or cartilage for a degenerating joint in the next 10 years, but reports that more complex organs are not to be expected in the next 20. However, in the meantime, scientists from Princeton and John Hopkins report to have printed a bionic ear, although all hearing capacity is provided by sensors and they also acknowledge that it is far from something a human can use.

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Now, about the ethics considerations, it might be advisable to note that the main big targets of this kind of technology are transplants -possibly using the receptor’s tissue as a model for the printed one- and testing on living tissue. Whereas it undoubtfully seems better to use printed stuff than animals for these applications, it might bring to the mind of the most paranoid readers movies like the Island or comicbooks like World of Krypton.

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