Graphene from Graphite by Electrochemical Exfoliation

Graphene is an interesting material, but making enough of the stuff to do something useful can be a little tough. That’s why we’re always on the lookout for new methods, like this electrochemical process for producing graphene in bulk.

You probably know that graphene is a molecular monolayer of carbon atoms linked in hexagonal arrays. Getting to that monolayer is a difficult proposition, but useful bits of graphene can be created by various mechanical and chemical treatments of common graphite. [The Thought Emporium]’s approach to harvesting graphene from graphite is a two-step process starting with electrochemical exfoliation. Strips of thin graphite foil are electrolyzed in a bath of ferrous sulfate, resulting in the graphite delaminating and flaking off into the electrolyte. After filtering and cleaning, the almost graphene is further exfoliated in an ultrasonic cleaner. The result is gram quantity yields with very little work and at low cost.

There’s plenty of effort going into new methods of creating graphene these days, whether by barely controlled explosions or superheating soybean oil. But will graphene be the Next Big Thing? The jury is still out on that.

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Grow Your Own Tin Crystals

[The Plutonium Bunny] saw homegrown tin crystals on YouTube and reckoned he could do better—those crystals were flimsy and couldn’t stand up outside of the solution in which they were grown. Having previously tackled copper crystals, he applied the same procedure to tin.

Beginning with a 140 ml baby food jar filled with a solution of tin II chloride, 90 grams per liter, with a small amount of HCl as the electrolyte. A wire at the bottom of the jar was connected to a blob of tin and served as the anode, while the cathode, a loop of tin, stuck down from above. A LM317-based adjustable voltage regulator circuit was used to manage the power running through the solution. Because [The Plutonium Bunny]’s technique involves days or even weeks of very low current, he used six diodes to drop the circuit’s voltage from 1.5 V to 0.25 V, giving him around 13 mA.

His first attempt seemed to go well and he got some nice shiny crystal faces, but he couldn’t get the current bellow 10 mA without it dropping to the point where no tin was depositing. Rather than reset the experiment he made some changes to the project: he changed the solution by removing 30 ml of the electrolyte and topping it off with water. He also made a gentle agitator out of a DC motor and flattened plastic tube from a pen, powering it with another low-voltage LM317 circuit so he could get the lowest RPM possible.

With this new setup [The Plutonium Bunny] began to get much  better results, proving his hypothesis that low current with a lower concentration of Sn2+ was the ticket for large crystal growth. We featured his copper crystal experiments last year and he’s clearly making good progress! Video after the break.

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Fluorescence Microscopy Meets DIY Fluid Management

Fluorescence microscopy is an optical technique that incorporates fluorescence or phosphorescence (as opposed to reflection and absorption) in order to study the properties of organic and inorganic substances. Not a stranger to bringing DIY techniques into the lab, [Philip] is using 3D printing resources to advance science and delight interns from labs everywhere.

In fluorescence microscopy, a huge limiting factor that decreases the amount of data that can be gleaned from a single sample is the number of targets that can be labeled with fluorescent tags. However, overlap in the spectral emissions of fluorophores limits the fluorophores that can be used side-by-side. This means that only around four targets can be labeled with fluorescent tags in a typical setup, with ten being the absolute maximum if careful spectral demixing is done. However, in a single sample, there might be a few hundred components. Clearly, we’re off by an order of magnitude (or more).

However, researchers are smart. One current solution is to label targets in a sequential manner with probe signal nullification steps in between. Ideally, probes are introduced in sequential without moving the sample off of the microscope. After imaging, the probes can be removed, allowing the number of labeled targets to be limited only to the number of rounds of probe replacement. And, with clever ‘barcoding’ schemes, the returns from each round can even scale exponentially, rather than linearly.

But, to accomplish this feat, a single sample must be processed through the labeling and stripping steps repeatedly. It’s not uncommon to do this by hand, consisting of many hours of exceptionally tedious work. That’s where [Philip] comes in. By using a 3D printer like Cartesian robot, [Philip] is automating the labeling and stripping steps resulting in happy interns and ultimately a more precise product. Rather than spending a few tens of thousands on a commercial machine, you can find all of [Philip’s] design files in his GitHub repo and make one for ~ $1k. Ready for more? We’ve got your back.

Video after the break.

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Re-Creating the Apollo DSKY’s Display

Apollo astronauts used the DSKY (Display-Keyboard) to interact with the flight computer with a series of 2-digit codes punched into a numeric keypad. Above the keyboard was a high voltage electroluminescent (EL) display whose segments were driven by electromechanical relays; old-ass technology not seen in operation in decades.

[Fran Blanche] is working to re-create the DSKY’s display, and is raising funds to make her first prototype. She was actually able to go dismantle a real DSKY at the Smithsonian, and this drove her desire to re-create the DSKY’s unusual display.

As [Fran] points out in her video, cinematic re-creations typically involve LED displays and CGI rather than the authentic EL 7-segs. Who would want that when you could have the original?

The DSKY is one of the most recognizable and historically relevant parts of the Apollo Command Module and it’s also quite rare. There are only a handful of  them around and of course none of them work. [Fran]’s display could help museums, collectors — and yes, moviemakers — re-create DSKYs with greater authenticity.

[Fran] is a good friend of Hackaday. If you missed her Hack Chat on antiquated technology last Friday you can check out the transcript here.

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Self-assembling Polymers Support Silicone 3D Prints

We all know what the ultimate goal of 3D printing is: to be able to print parts for everything, including our own bodies. To achieve that potential, we need better ways to print soft materials, and that means we need better ways to support prints while they’re in progress.

That’s the focus of an academic paper looking at printing silicone within oil-based microgels. Lead author [Christopher S. O’Bryan] and team from the Soft Matter Research Lab at the University of Florida Gainesville have developed a method using self-assembling polymers soaked in mineral oil as a matrix into which silicone elastomers can be printed. The technique takes advantage of granular microgels that are “jammed” into a solid despite being up to 95% solvent. Under stress, such as that exerted by the nozzle of a 3D printer, the solid unjams into a flowing liquid, allowing the printer to extrude silicone. The microgel instantly jams back into a solid again, supporting the silicone as it cures.

[O’Bryan] et al have used the technique to print a model trachea, a small manifold, and a pump with ball valves. There are Quicktime videos of the finished manifold and pump in action. While we’ve covered flexible printing options before, this technique is a step beyond and something we’re keen to see make it into the hobby printing market.

[LonC], thanks for the tip.

Get into Biohacking on the Cheap with this Electrophoresis Rig

If you want to get into electronics, it’s pretty straightforward: read up a little, buy a breadboard and some parts, and go to town. Getting into molecular biology as a hobby, however, presents some challenges. The knowledge is all out there, true, but finding the equipment can be a problem, and what’s out there tends to be fiendishly expensive.

So many would-be biohackers end up making their own equipment, like this DIY gel electrophoresis rig. Electrophoresis sorts macromolecules like DNA or proteins by size using an electric field. For DNA, a slab of agarose gel is immersed in a buffer solution and a current through the tank moves the DNA through the gel. The shorter the DNA fragment, the easier it can wiggle through the pores in the gel, and the faster it migrates down the gel. [abizar]’s first attempt at a DIY gel rig involved a lot of plastic cutting and solvent welding, so he simplified the process by using the little plastic drawers from an old parts cabinet. With nichrome and platinum wires for electrodes for the modified ATX power supply, it’s just the right size and shape for the gel, which is cast in a separate mold. The video below shows the whole build, and while [abizar] doesn’t offer much detail on recipes or techniques, there are plenty of videos online to guide you.

Need more apparatus to deck out your lab? We’ve got you covered there too.

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To Deal with Plastic Trash, All You Need is Bugs

Outlawed now in some places, or only available to tote your purchases at a ridiculous premium, the billions of “T-shirt” bags used every year present a serious waste management problem. Whether blowing across the landscape like synthetic tumbleweeds, floating in the ocean as ersatz jellyfish, or clogging up municipal waste streams, finding a way to deal with them could really make a difference. And finding a bug that eats polyethylene and poops antifreeze might be a great first step in bioremediating the mess.

As with many scientific discoveries, learning about the useful and unexpected eating habits of the larval stage of the Greater Wax Moth Galleria mellonella can be chalked up to serendipity. It began when biochemist [Federica Bertocchini] cleaned a wax moth infestation from her beehive. She put the beeswax-loving pests in a plastic bag, later finding they had chewed their way out. Intrigued, she and [Paolo Bombelli] ran some experiments using the bugs. They showed the mechanism wasn’t just mechanical and that the worms were digesting the polyethylene, to the tune of 92 mg consumed for 100 worms in 12 hours. That’s about 1,000 times faster than bioremediation with bacteria.

Furthermore, the bugs excrete ethylene glycol, a useful industrial chemical, in the process. Finally, to see if the process can scale, the researchers showed that a homogenate of wax moth larvae could digest PE sheets. This could lead to an industrial process if the enzymes involved can be isolated and engineered. The letter describing the process is a fascinating read.

While this one may not a classically hackish way to deal with plastic recycling, the potential for this method is huge. We look forward to seeing where this goes.

[Images: César Hernández/CSIC]