Green fluorescent protein

Tweaked Germs Glow to Pinpoint Buried Landmines

laser system
laser system

Landmines are explosive wartime weapons. People bury them or leave them on the ground for their enemies to step on or drive over. Yet once peacetime arrives, some of these buried bombs may remain behind. They’re often in empty fields, where they can maim or kill innocent civilians. But a new technology can make it easy to find landmines — even from a safe distance. And this might let bomb crews disarm these weapons before someone gets hurt.

The International Campaign to Ban Landmines (ICBL) is a group based in Geneva, Switzerland. It aims to end the use of these explosives. These mines had become such a big problem that an international Mine Ban Treaty was enacted in 1997. ICBL played a major role in getting countries to agree to the ban. For its success, ICBL and its coordinator — Jody Williams — shared the 1997 Nobel Peace Prize. Yet even today, millions of these bombs may still be buried out of sight across the world, according to the United Nations. In 2015 alone, the group notes, landmines and similar bombs killed or injured more than 5,000 civilians. Almost four in every 10 of the victims were children.

Trained workers typically go into a field with metal detectors to find and remove mines. But sometimes they don’t find the mines until they’re right on top of them, which can be very dangerous. That’s why the new technology is so promising. Using it, scouts now can identify landmines from a distance. Then they can send in experts to cautiously defuse or detonate the bombs.

Scientists described how their new system works April 11 in Nature Biotechnology.

Lasers and light-up germs

The research focused on what are called anti-personnel mines. Anti-personnel means these weapons have been set out to kill people: enemy soldiers. They explode when someone steps on them. (More powerful anti-tank mines, by contrast, are triggered only when heavier vehicles such as tanks or cars pass over them.)

Shimshon Belkin teaches biotechnology and environment sciences at the Hebrew University of Jerusalem in Israel. He knew that some microbes will happily eat and grow on particular pollutants. In his research, he has used these bacteria to find toxic chemicals.

“We demonstrated numerous times that we can engineer our bacterial sensors to detect and identify…

5 Labs That Use 3D Printing for Biohacking Projects

The greatest bridge between the world of makers and the world of biohackers is probably the mighty 3D printer. The main difference is instead of using plastics, they’re using biomaterials to build three-dimensional structures, and using special bioinks made of living cells to print messages and patterns.

Human cells cultured into a decellularized apple slice (left) and an apple carved into an ear shape (right) from Pelling Labs. Photo by Bonnie Findley

How BioCurious Started Bioprinting

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BioCurious is a mandatory stop among biohacker communities in North America. This pioneering space, located in Sunnyvale, California, hosts a number of great people collaborating on the DIY BioPrinter project. Their bioprinting adventure started in 2012, when they had their first meetups. According to Patrik D’haeseleer, who is leading the project with Maria Chavez, they were looking for community projects that could bring new people into the space and let them quickly collaborate. None of the project leaders had a specific bioprinting application in mind, nor did they have previous knowledge on how to build this kind of printer. Still, it appeared to be a fairly approachable technology that people could play with.

“You can just take a commercial inkjet printer. Take the inkjet cartridges and cut off the top essentially. Empty out the ink and put something else in there. Now you can start printing with that,” D’haeseleer explains.

The BioCurious group started by printing on big coffee filters, substituting ink with arabinose, which is a natural plant sugar. Then they put the filter paper on top of a culture of E. coli bacteria genetically modified to produce a green fluorescent protein in the presence of arabinose. The cells started to glow exactly where arabinose was printed.

Modifying commercial printers for this, as they were doing, presented challenges. “You may need to reverse engineer the printer driver or disassemble the paper handling machinery in order to be able to do what you want,” says D’haeseleer.

First major success with BioCurious’ $150 DIY BioPrinter: fluorescent E. coli printed on agar with an inkjet printhead. Photo by Patrik Dʼhaeseleer

So the group decided to build their own bioprinter from scratch. Their second version uses stepper motors from CD drives, an inkjet cartridge as a print head, and an open source Arduino shield to drive it — a DIY bioprinter for just $150 that you can find on Instructables.

The next and still current challenge deals with the consistency of the ink. Commercial cartridges work with ink that is pretty watery. But bioink requires a more gel-like material with high viscosity. The DIY BioPrinter group has been experimenting with different syringe pump designs that could allow them to inject small amounts of viscous liquid through the “bio print head.”

BioCurious’ early printer: $11 syringe pumps mounted on a platform made from DVD drives. Photo by Patrik Dʼhaeseleer

Moving to 3D

Starting with an already existing 3D platform seemed like the best way to go beyond 2D patterns. The group first tried to modify their existing 3D printer by adding a bio print head directly on it. However, their commercial machine required some difficult reverse engineering and software modification to perfect the process. After a couple of months, this led to a dead end.

The RepRap family of 3D printers influenced the next step. After buying an affordable open source printer kit, the bioprinting team was able to switch out the plastic extruding print head for a print head with flexible tubes that connected to a set of stationary syringe pumps. It worked.

Converting a RepRap into BioCurious’ latest 3D BioPrinter platform, with an Open…