Implant Fights Diabetes By Making Insulin And Oxygen

October 10, 2023 by Dan Maloney 13 Comments

Type 1 diabetes remains a problem despite having an apparently simple solution: since T1D patients have lost the cells that produce insulin, it should be possible to transplant those cells into their bodies and restore normal function. Unfortunately, it’s not actually that simple, and it’s all thanks to the immune system, which would attack and destroy transplanted pancreas cells, whether from a donor or grown from the patient’s own stem cells.

That may be changing, though, at least if this implantable insulin-producing bioreactor proves successful. The device comes from MIT’s Department of Chemical Engineering, and like earlier implants, it relies on encapsulating islet cells, which are the insulin-producing cells within the pancreas, inside a semipermeable membrane. This allows the insulin they produce to diffuse out into the blood, and for glucose, which controls insulin production in islet cells, to diffuse in. The problem with this arrangement is that the resource-intensive islet cells are starved of oxygen inside their capsule, which is obviously a problem for the viability of the implant.

The solution: electrolysis. The O₂-Macrodevice, as the implant is called, uses a tiny power-harvesting circuit to generate oxygen for the islet cells directly from the patient’s own interstitial water. The circuit applies a current across a proton-exchange membrane, which breaks water molecules into molecular oxygen for the islet cells. The hydrogen is said to diffuse harmlessly away; it seems like that might cause an acid-base imbalance locally, but there are plenty of metabolic pathways to take care of that sort of thing.

The implant looks promising; it kept the blood glucose levels of diabetic mice under control, while mice who received an implant with the oxygen-generating cell disabled started getting hyperglycemic after two weeks. What’s really intriguing is that the study authors seem to be thinking ahead to commercial production, since they show various methods for mass production of the cell chamber from standard 150-mm silicon wafers using photolithography.

Type 1 diabetics have been down the “artificial pancreas” road before, so a wait-and-see approach is clearly wise here. But it looks like treating diabetes less like a medical problem and more like an engineering problem might just pay dividends.

Creating An Automated Hydrogen Generator At Home

October 6, 2023 by Maya Posch 33 Comments

Everyone and their pet hamster probably knows that the most common way to produce hydrogen is via the electrolysis of water, but there are still a number of steps between this elementary knowledge and implementing a (mostly) automated hydrogen generator. Especially if your end goal is to create liquid hydrogen when everything is said and done. This is where [Hyperspace Pirate]’s latest absolutely not dangerous project commences, with the details covered in the recently published video.

Automated hydrogen generator setup, courtesy of [Hyperspace Pirate]'s dog drinking bowl. — Automated hydrogen generator setup, courtesy of [Hyperspace Pirate]’s dog drinking bowl.

Since electrolysis cannot occur with pure water, sodium hydroxide (NaOH) is used in the solution to provide the ions. The electrodes are made of 316 stainless steel, mostly because this is cheap and good enough for this purpose. Although the original plan was to use a stacked series of electrodes with permeable membranes like in commercial electrolysers, this proved to be too much of a hassle to seal up leak-tight. Ergo the demonstrated version was attempted, where an upturned glass bell provides the barrier for the produced hydrogen and oxygen. With this system it’s easy to measure the volume of the produced hydrogen due to the displaced water in the bell.

Once enough hydrogen gas is produced, a vacuum pump is triggered by a simple pair of electrodes to move the hydrogen gas to a storage container. Due to hydrogen embrittlement concerns, an aluminium tank was used rather than a steel one. Ultimately enough hydrogen gas was collected to fill a lot of party balloons, and with the provided information in the video it should be quite straightforward to reproduce the system.

Where the automation comes into play is with a control system that monitors for example how long the vacuum pump has been running, and triggers a fail safe state if it’s more than a set limit. With the control system in place, [Hyperspace Pirate] was able to leave the hydrogen generator running for hours with no concerns. We’re hopeful that his upcoming effort to liquify this hydrogen will be as successful, or the human-rated blimp, or whatever all this hydrogen will be used for.

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Renewable Hydrogen Sucked From Thinish Air

September 11, 2022 by Dave Rowntree 26 Comments

Stored hydrogen is often touted as the ultimate green energy solution, provided the hydrogen is produced from genuinely green power sources. But there are technical problems to be overcome before your average house will be heated with pumped or tank-stored hydrogen. One problem is that the locations that have lots of scope for renewable energy, don’t always have access to plenty of pure water, and for electrolysis you do need both. A team from Melbourne University have come up with a interesting way to produce hydrogen by electrolysis directly from the air.

Redder areas have more water risk and renewable potential

By utilising a novel electrolysis cell with a hygroscopic electrolyte, the so-called direct air electrolysis (DAE) can operate with humidity as low as 4% relative, so perfectly fine even in the most arid areas, after all there may not be clouds but the air still holds a bit of water. This is particularly relevant to regions of the world, such as deserts, where there is simultaneously a high degree of water risk, and plenty of solar potential. Direct electrolysis of saline extracted at coastal areas is one option, but dealing with the liberated chlorine is a big problem.

The new prototype is very simple in construction, with a sponge of melamine or a sintered glass foam soaked in a compatible electrolyte. Potassium Hydroxide (alkaline) was tried as was Potassium Acetate (base) and Sulphuric Acid, but the latter degraded the host material in a short time. Who would have imagined? Anyway, with electrolysis cell design, a key problem is ensuring the separate gasses stay separate, and in this case, are also separate from the air. This was neatly ensured by arranging the electrolyte sponge fully covered both electrodes, so as the hygroscopic material extracted water from the air, the micro-channels in the structure filled up with liquid, with it touching both ends of the cell, forming the circuit and allowing the electrolysis to proceed.

Hydrogen, being very light, would rise upward through holes in the cathode, to be collected and stored. Oxygen simply passed back into the air, after passing though the liquid reservoir at the base. Super simple, and from reading the paper, quite effective too.

You can kind of imagine a future built around this now, where you’re driving your hydrogen fuel cell powered dune buggy around the Sahara one weekend, and you stop at a solar-powered hydrogen fuel station for a top up and a pasty. Ok, possibly not that last bit.

The promised hydrogen economy may be inching closer. We covered using aluminium nanoparticles to rip hydrogen out of water. But once you have the gas, you need to store and handle it. Toyota might have a plan for that. Then perhaps handling gas directly at all isn’t a great idea, and maybe the future is paste?

Thanks to [MmmDee] for the tip!

Brass Plaque Honors Brother

August 3, 2022 by Brian McEvoy 10 Comments

Brass plaques are eye-catching because no one makes them on a whim. They are more costly than wood or plastic, and processing them is proportionally difficult. [Becky Stern] picked the medium to honor her brother, who enjoyed coffee, motorcycles, and making things by hand. She made some playing card-sized pieces to adorn his favorite brand of hot bean juice and a large one to hang at his memorial site.

The primary components are a vertical salt water bath, DC power supply, metal to etch, scrap steel approximately the same size, and a water agitator, which in this case is an air pump and diffuser stone. You could stir manually for two hours and binge your shows but trust us and take the easy route. The video doesn’t explicitly call for flexible wires, but [Becky] wisely selected some high-strand hook-up leads, which will cause fewer headaches as stiff copper has a mind of its own, and you don’t want the two sides colliding.

There are a couple of ways to transfer an insulating mask to metal, and we see the ole’ magazine paper method fail in the video, but cutting vinyl works a treat. You may prefer lasers or resin printers, and that’s all right too. Once your mask is sorted, connect the positive lead to the brass and the negative to your steel. Now, it’s into the agitated salt water bath, apply direct current, and allow electricity to immortalize your design.

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This Motorcycle Uses Water!

April 2, 2022 by Jenny List 38 Comments

Doing the rounds among motorcycle enthusiasts for the last week has been a slightly unusual machine variously portrayed as running on water or sea water. This sounds like the stuff of the so-called “Free energy” fringe and definitely not the normal Hackaday fare, but it comes alongside pictures of a smiling teenager and what looks enough like a real motorcycle to have something behind it. So what’s going on? The answer is that it’s the student project of an Argentinian teenager [Santiago Herrera], and while it’s stretching it a bit to say it runs on sea water he’s certainly made a conventional motorcycle run on the oxygen-hydrogen mix produced from the electrolysis of water. The TikTok videos are in Spanish, but even for non-speakers it should be pretty clear what’s going on.

It’s obvious that the bike is more of a student demonstrator than a road machine, as we’re not so sure a glass jar is the safest of receptacles. But the interesting part for us lies not in the electrolysis but in the engine. it appears to be a fairly standard looking motorcycle engine, a typical small horizontal single. It’s running on a stoichiometric mix of oxygen and hydrogen, something that packs plenty of punch over a similar mix using air rather than oxygen. It would be fascinating to know the effect of this mixture on an engine designed for regular gasoline, for example does it achieve complete combustion, does it burn hotter than normal fuel, and does it put more stress on the engine parts?

You can see something of the bike in the video below the break, and there are a few more videos in his TikTok account. Meanwhile this isn’t the first teenage motorcycle project we’ve featured.

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Building A Lightsaber And Scoring A World Record, Too

January 25, 2022 by Lewin Day 32 Comments

As we all know, the lightsaber is an elegant weapon, for a more civilized age. [Alex Burkan] is doing what he can to bring that technology to fruition, and even secured a Guinness World Record in the process.

The build relies on an electrolyzer, splitting water into hydrogen and oxygen gas which is stored in a small tank. This gas can then be released and combusted in a burning stream, creating a weapon with a vague resemblance to a movie-spec lightsaber. With the hydrogen torch burning at temperatures of thousands of degrees, it’s hot enough to melt steel just like in the films.

While the concept of operation is simple, actually building such a device in a handheld size is incredibly difficult. [Alex] highlights key features such as the flashback arrestor that stops the gas tank exploding, and the output nozzle that was carefully designed to produce a surprisingly long and stable flame.

The resulting device only burns for 30 seconds, so you’ve only got a short period of time to do what you need to do. However, unlike previous designs we’ve seen, it doesn’t use any external gas bottles and is entirely self-contained, marking an important step forward in this technology. Video after the break.

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3D-Printed Tooling Enables DIY Electrochemical Machining

July 29, 2021 by Dan Maloney 10 Comments

When it comes to turning a raw block of metal into a useful part, most processes are pretty dramatic. Sharp and tough tools are slammed into raw stock to remove tiny bits at a time, releasing the part trapped within. It doesn’t always have to be quite so violent though, as these experiments in electrochemical machining suggest.

Electrochemical machining, or ECM, is not to be confused with electrical discharge machining, or EDM. While similar, ECM is a much tamer process. Where EDM relies on a powerful electric arc between the tool and the work to erode material in a dielectric fluid, ECM is much more like electrolysis in reverse. In ECM, a workpiece and custom tool are placed in an electrolyte bath and wired to a power source; the workpiece is the anode while the tool is the cathode, and the flow of charged electrolyte through the tool ionizes the workpiece, slowly eroding it.

The trick — and expense — of ECM is generally in making the tooling, which can be extremely complicated. For his experiments, [Amos] took the shortcut of 3D-printing his tool — he chose [Suzanne] the Blender monkey — and then copper plating it, to make it conductive. Attached to the remains of a RepRap for Z-axis control and kitted out with tanks and pumps to keep the electrolyte flowing, the rig worked surprisingly well, leaving a recognizably simian faceprint on a block of steel.

[Amos] admits the setup is far from optimized; the loop controlling the distance between workpiece and tool isn’t closed yet, for instance. Still, for initial experiments, the results are very encouraging, and we like the idea of 3D-printing tools for this process. Given his previous success straightening his own teeth or 3D-printing glass, we expect he’ll get this fully sorted soon enough.