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.

How Peptides Are Made

What does body building, anti-aging cream and Bleomycin (a cancer drug) have in common? Peptides of course! Peptides are large molecules that are vital to life. If you were to take a protein and break it into smaller pieces, each piece would be called a peptide. Just like proteins, peptides are made of amino acids linked together in a chain-like structure. Whenever you ingest a protein, your body breaks it down to its individual amino acids. It then puts those amino acids back together in a different order to make whatever peptide or protein your body needs. Insulin, for instance, is a peptide that is 51 amino acids long. Your body synthesizes insulin from the amino acids it gets from the proteins you eat.

Peptides and small proteins can be synthesized in a lab as well. Peptide synthesis is a huge market in the pharmaceutical and skin care industry. They’re also used, somewhat shadily, as a steroid substitute by serious athletes and body builders. In this article, we’re going to go over the basic steps of how to join amino acids together to make a peptide. The chemistry of peptide synthesis is complex and well beyond the scope of this article. But the basic steps of making a peptide are not as difficult as you might think. Join me after the break to gain a basic understanding of how peptides are synthesized in labs across the world, and to establish a good footing should you ever wish to delve deeper and make peptides on your own.

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Synthetic Biology Creates Living Computers

Most people have at least a fuzzy idea of what DNA is. Ask about RNA, though, and unless you are talking to a biologist, you are likely to get even more handwaving. We hackers might have to reread our biology text books, though, since researchers have built logic gates using RNA.

Sometimes we read these university press releases and realize that the result isn’t very practical. But in this case, the Arizona State University study shows how AND, OR, and NOT gates are possible and shows practical applications with four-input AND gates and six-input OR gates using living cells. The key is a construct known as an RNA toehold switch (see video below). Although this was worked out in 2012, this recent study shows how to apply it practically.

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Stealing Joules From An Aluminium-Air Battery

While batteries are cheap and readily obtainable today, sometimes it’s still fun to mess around with their less-common manifestations. Experimenting with a few configurations, user [will.stevens] has assembled an aluminium-air battery and combined it with a joule thief to light an LED.

To build the air battery, soak an activated charcoal puck — from a water filter, for example — in salt-saturated water while you cut the base off an aluminium can. A circle of tissue paper — also saturated with the salt water — is pressed between the bare charcoal disk and the can, taking care not to rip the paper, and topped off with a penny and a bit of wire. Once clamped together, the reaction is able to power an LED via a simple joule thief.

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SCiO “Pocket Molecular Scanner” Teardown

Some of you may remember the SCiO, originally a Kickstarter darling back in 2014 that promised people a pocket-sized micro spectrometer. It was claimed to be able to scan and determine the composition of everything from fruits and produce to your own body. The road from successful crowdsourcing to production was uncertain and never free from skepticism regarding the promised capabilities, but the folks at [Sparkfun] obtained a unit and promptly decided to tear it down to see what was inside, and share what they found.

The main feature inside the SCiO is the optical sensor, which consists of a custom-made NIR spectrometer. By analyzing the different wavelengths that reflect off an object, the unit can make judgments about what the object is made of. The SCiO was clearly never built to be disassembled, but [Sparkfun] pulls everything apart and provides some interesting photos of a custom-made optical unit with an array of different sensors, various filters, apertures, and a microlens array.

It’s pretty interesting to see inside the SCiO’s hardware, which unfortunately required destructive disassembly of the unit in question. The basic concept of portable spectroscopy is solid, as shown by projects such as the Farmcorder which is intended to measure plant health, and the DIY USB spectrometer which uses a webcam as the sensor.

Anyone Need a Little Fuming Nitric Acid?

If there’s a chemical with a cooler name than “fuming nitric acid,” we can’t think of it. Nearly pure nitric acid is useful stuff, especially if you’re in the business of making rocket fuels and explosives. But the low-end nitric acid commonly available tops out at about 68% pure, so if you want the good stuff, you’ll have to synthesize fuming nitric acid yourself. (And by “good stuff”, we mean be very careful with the resulting product.)

Fuming nitric acid comes in two colors – red fuming nitric acid (RFNA), which is about 90% pure and has some dissolved nitrogen oxides, giving it its reddish-brown color. White fuming nitric acid (WFNA) is the good stuff — more than 99% pure. Either one is rough stuff to work with — you don’t want to wear latex or nitrile gloves while using it. It’s not clear what [BarsMonster] needs the WFNA for, although he does mention etching some ICs. The synthesis is pretty straightforward, if a bit dangerous. An excess of sulfuric acid is added to potassium nitrate, and more or less pure nitric acid is distilled away from the resulting potassium sulfate. Careful temperature control is important, and [BarsMonster] seems to have gotten a good yield despite running out of ice.

We don’t feature too many straight chemistry hacks around here, but this one seemed gnarly enough to be interesting. We did have a Hackaday Prize entry a while back on improvements to the Haber process for producing ammonia, which curiously is the feedstock for commercial nitric acid production processes.

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