Cheap 3D Printers Make Cheaper(er) Bioprinters

In case you missed it, prices on 3D printers have hit an all time low. The hardware is largely standardized and the software is almost exclusively open source, so it makes sense that eventually somebody was going to start knocking these things out cheap. There are now many 3D printers available for less than $300 USD, and a few are even dipping under the $200 mark. Realistically, this is about as cheap as these machines are ever going to get.

A startup by the name of 3D Cultures has recently started capitalizing on the availability of these inexpensive high-precision three dimensional motion platforms by co-opting an existing consumer 3D printer to deliver their Tissue Scribe bioprinter. Some may call this cheating, but we see it for what it really is: a huge savings in cost and R&D time. Why design your own kinematics when somebody else has already done it for you?

Despite the C-3PO level of disguise that 3D Cultures attempted by putting stickers over the original logo, the donor machine for the Tissue Scribe is very obviously a Monoprice Select Mini, the undisputed king of beginner printers. The big change of course comes from the removal of the extruder and hotend, which has been replaced with an apparatus that can heat and depress a standard syringe.

At the very basic level, bioprinting is performed in the exact same way as normal 3D printing; it’s merely a difference in materials. While 3D printing uses molten plastic, bioprinting is done with organic materials like algae or collagen. In the Tissue Scribe, the traditional 3D printer hotend has been replaced with a syringe full of the organic material to be printed which is slowly pushed down by a NEMA 17 stepper motor and 8mm leadscrew.

The hotend heating element and thermistor that once were used to melt plastic are still here, but now handle warming the metal frame used to hold the syringe. In theory these changes would have only required some tweaks to the firmware calibration to get working. Frankly, it makes perfect sense, and is certainly a much easier to pull off than some of the earlier attempts at homebrew biological printers we’ve seen.

We won’t comment on the Tissue Scribe’s price point of $999 USD except to say that in the field of bioprinters, that’s pocket change. Still, it seems inevitable that somebody will build and document their own bolt-on biological extruder now that 3D Cultures has shown how simple it really is, so they may find themselves undercut in the near future.

If all this talk of hot extruded collagen has got you interested, we’ve seen some excellent resources on the emerging field of bioprinting that will probably be right up your alley.

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Carbon Quantum Dots in Your Favorite Color

Citizen scientist extraordinaire [Thought Emporium] put out a new video about colorful quantum dots which can be seen below the break. Quantum dots are a few nanometers wide and you can tell which size they are by which color they fluoresce. Their optical and electrical properties vary proportionally with size so red will behave differently than purple but we doubt they will taste like “cherry” and  “grape.” Let’s not find out. This makes sense when you realize that a diamond will turn into black powder if you pulverize it. Carbon is funny like that.

[Thought Emporium] uses the video for two purposes. The first is to demonstrate the process he uses to make different size quantum dot in his home lab. The second purpose is to implore the scientific community, in general, to take better care when publishing scientific papers. A flimsy third reason is to show that the show must go on. Partway through, all the batteries for his light were dead so he hastily soldered a connection for his benchtop power supply.

We’ve mentioned [Thought Emporium] a few times before. Another of his carbon-based experiments involved graphene creation. How about magnetic DNA extraction? [Thought Emporium] did that too. If you can’t get enough magnets, how about implanting one?

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Making Ice Cream With Heavy Metal

After his last project left him with an eleven-pound block of aluminum, [Jason] got to thinking of what most of us would in that situation: fresh made ice cream. His mind was on the frozen concoctions of the aptly named Cold Stone Creamery, a mall food court staple where a chilled stone is used to turn fresh ingredients into made to order sundaes.

[Jason] did the math and found that an eleven-pound chunk of aluminum can absorb a little over 67,000 joules, which is over twice the energy required to freeze 100 g of water. In place of water he would be using cream, condensed milk, and strawberries, but believed there was a large enough safety factor to account for the differences between his ingredients and pure water.

His first attempt didn’t go exactly as planned, but with his Flir One he was able to back up his theoretical numbers with some real-world data. He found that he needed to start the aluminum block at a lower temperature before adding his ingredients, and through experimentation determined the block only had enough energy to freeze 30 g of liquid.

In the end [Jason] was satisfied with the frozen treat he managed to make from the leftovers of his radial mill project, but theorizes that an ever better solution would be to use a brine solution and drop the aluminum block all together.

Of course, if putting food on a slab of metal from your workshop doesn’t sound too appealing, you could always go the NASA route and freeze dry it. Either method will probably make less of a mess than trying to print objects with it.

The Hackaday Prize: Growing Your Own Soil

When a rainforest is clearcut for agricultural use, we only see the surface problems: fewer trees, destruction of plant and animal habitats, and countless other negative effects on the environment. A lurking problem, however, is that the soil is often non-ideal for farming. When the soil is exhausted, the farmers move further into the rainforest and repeat the process.

In the Amazon, however, there are pockets of man-made soil that are incredibly nutrient-dense. Figuring out how to make this soil, known as Terra Preta, on a massive scale would limit the amount of forest destruction by providing farmers a soil with more longevity which will, in turn, limit the encroachment on the rainforest. That’s the goal of this Hackaday Prize entry by [Leonardo Zuniga]: a pyrolysis chemical reactor that can make this soil by turning organic matter into a type of charcoal that can be incorporated into the soil to make Terra Preta.

As a bonus to making this nutrient-dense soil on a massive scale, this reactor also generates usable energy as a byproduct of processing organic waste, which goes several steps beyond simple soil enrichment. If successful and scalable, this project could result in more efficient farming techniques, greater yields, and, best of all, less damage to the environment and less impact on the rainforests.

NIST uses Optical Resonance to Probe Atoms

Have you ever stood under a dome and whispered, only to hear the echo of your voice come back much louder? Researchers at NIST used a similar principle to improve the atomic force microscope (AFM), allowing them to measure rapid changes in microscopic material more accurately than ever before.

An AFM works by using a minuscule sharp probe. The instrument detects deflections in the probe, often using a piezoelectric transducer or a laser sensor. By moving the probe against a surface and measuring the transducer’s output, the microscope can form a profile of the surface. The NIST team used a laser traveling through a circular waveguide tuned to a specific frequency. The waveguide is extremely close (150 nm) to a very tiny probe weighing about a trillionth of a gram. When the probe moves a very little bit, it causes the waveguide’s characteristics to change to a much larger degree and a photodetector monitoring the laser light passing through the resonator can pick this up.

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Cheap and Easy Magnetic DNA Separation Method Needs Your Help

When you consider that almost every single cell in your body has more than a meter of DNA coiled up inside its nucleus, it seems like it should be pretty easy to get some to study. But with all the other cellular gunk in a crude preparation, DNA can be quite hard to isolate. That’s where this cheap and easy magnetic DNA separation method comes in. If it can be optimized and tested with some help from the citizen science community.

Commercial DNA separation methods generally involve mixing silica beads into crude cell fractions; the DNA preferentially binds to the silica, making it possible to mechanically separate it from the rest of the cellular junk. But rather than using a centrifuge to isolate the DNA, [Justin] from The Thought Emporium figured that magnets might do a better job. It’s not a new idea — biotech companies offer magnetic separation beads commercially, but at too steep a price for [Justin]’s budget. His hack comes from making magnetite particles from common iron compounds like PCB etchant and moss killer, and household ammonia cleaner. The magnetite particles are then coated with sodium silicate solution, also known as waterglass. The silica coating should allow the beads to bind to DNA, with the magnetic core taking care of separation.

[Justin] was in the process of testing his method when he lost access to the needed instruments, so he’s appealing to the larger science community for help optimizing his technique. Based on his track record of success in fields ranging from satellite tracking to graphene production, we’ll bet he’ll nail this one too.

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Blast Your Battery’s Sulphates, Is It Worth It?

When a friend finds her caravan’s deep-cycle battery manager has expired over the summer, and her holiday home on wheels is without its lighting and water pump, what can you do? Faced with a dead battery with a low terminal voltage in your workshop, check its electrolyte level, hook it up to a constant current supply set at a few hundred mA, and leave it for a few days to slowly bring it up before giving it a proper charge. It probably won’t help her much beyond the outing immediately in hand, but it’s better than nothing.

A lot of us will own a lead-acid battery in our cars without ever giving it much thought. The alternator keeps it topped up, and every few years it needs replacing. Just another consumable, like tyres or brake pads. But there’s a bit more to these cells than that, and a bit of care and reading around the subject can both extend their lives in use and help bring back some of them after they have to all intents and purposes expired.

One problem in particular is sulphation of the lead plates, the build-up of insoluble lead sulphate on them which increases the internal resistance and efficiency of the cell to the point at which it becomes unusable. The sulphate can be removed with a high voltage, but at the expense of a dangerous time with a boiling battery spewing sulphuric acid and lead salts. The solution therefore proposed is to pulse it with higher voltage spikes over and above charging at its healthy voltage, thus providing the extra kick required to shift the sulphation build up without boiling the electrolyte.

If you read around the web, there are numerous miracle cures for lead-acid batteries to be found. Some suggest adding epsom salts, others alum, and there are even people who talk about reversing the charge polarity for a while (but not in a Star Trek sense, sadly). You can even buy commercial products, little tablets that you drop in the top of each cell. The problem is, they all have the air of those YouTube videos promising miracle free energy from magnets about them, long on promise and short on credible demonstrations. Our skeptic radar pings when people bring resonances into discussions like these.

So so these pulse desulphators work? Have you built one, and did it bring back your battery from the dead? Or are they snake oil? We’ve featured one before here, but sadly the web link it points to is now only available via the Wayback Machine.