Images courtesy of IBM

Many good things happen when you pop your used plastic bottles in with the recycling – you conserve resources, save energy, preserve landfill space and start off a process that can result in new bottles, plastic furniture or even a cosy fleece jumper. Soon, though, the simple act of separating out drinks bottles could turn into a feat of heroic proportions, becoming the first step in tackling drug-resistant superbugs – if scientists at IBM have their way.

Researchers at IBM’s Almaden research centre, in collaboration with the Institute of Bioengineering and Nanotechnology (IBN), Singapore, have made what they’re calling a ‘nanotechnology breakthrough’. They’ve converted polyethylene terephthalate (PET) from waste plastic bottles into ‘biocompatible’ materials that specifically target and attack bacterial and fungal infections – including drug-resistant killers like methicillin-resistant Staphylococcus aureus (MRSA), involved in 0.2 per cent of all UK hospital deaths between 2008 and 2012.

These ninja polymers, as the team is playfully calling them, differ from traditional antibiotics to which some bacteria develop resistance. Research Team Member Amanda Engler explains: “We believe that the ninja polymers will work on the outer membrane, whereas the traditional antibiotics work on the inner workings of the cell, attacking cell division, for example, or other important machinery that the cell needs to survive. So, with the traditional antibiotics, what happens is your fungus mutates and through these mutations, it develops a resistance. We anticipate that if the ninja polymers work on the outside of the fungus, it’s going to be much less likely to develop resistance.” And initial trials look promising: working in collaboration with IBN in Singapore, the scientistshave found that fungi exposed to 12 sub-lethal doses of the new medicine are not developing any resistance to the drugs. This compares to conventional antifungal medicines, to which pesky bacteria exhibited drug resistance after just six treatments.

The team has designed the polymers to be positively charged, meaning that, unlike traditional antibiotics, they only interact with negatively-charged fungal cells and don’t attack neutrally-charged mammalian cells. Instead, they insert themselves into infected cells’ membranes, which is “like taking a needle into the membrane of a balloon – it just pops open and it spills out everything”, according to Engler.

But the positive charge is the scientists’ final step in manipulating the materials at the subatomic level – there are several other procedures involved in transforming waste plastic bottles into ninja polymers, the first of which is scrambling to collect as many used bottles as possible: “Literally, when this project first started, they would go up and down the hallways here and collect bottles and cut them up. It’s something that is very readily available, to us it’s free material.”

The rest of the process is a bit more complicated, however; Engler takes me through it: “PET is a polyester, and what we’re able to do with PET is break it down via the ester linkages… In this instance, we’ve taken bottles that have wrappers and caps, and you try and separate out as much as you can, but you’re still left with some other plastics as well as the paper. And you put it into a flask or a container holding a reaction solution and heat up the stirring solution, and you can watch the plastic breaking down and dissolving into the solution. And when the solution’s warm, all the other paper and plastics can be filtered right out. As you let the solution cool down, the basic monomer crystalises out, and that’s what we’re using to create these ninja polymers.” Engler says that, following the purification step, the material is 99.9 per cent pure; the scientists then react this basic monomer with “either a long-chain or something that has a ring structure in the middle of it” (more of which in a moment), and finally conduct what’s known as a “deprotection step” to reveal the positive charge on the outside of the polymers.

A thousand times smaller than a grain of sand, these polymers display a unique self-assembly process to form ‘super’ molecules through hydrogen bonding caused by the interaction of NH groups and oxygen molecules in covalent bonds; “the nitrogens, the NHs, like to hang out right next to the oxygens and stack on top of each other… I like to think of these zigzags as the ridges of poker chips”, Engler explains in layman’s terms. She’s clearly had a lot of practice helping non-scientists visualise the process, and she elaborates that the ring structures mentioned earlier also “are nice and flat and like to stack on top of each other” – again in the manner of poker chips – to create long, hydrophobic, worm-like assemblies. The assembly process increases their cationic charge, which allows them to selectively target and pop negatively-charged bacteria’s membranes.

Plastics are famously long-lived materials, with the scientific world saying it could take anywhere from 450 to a thousand years for a plastic bottle to begin to decompose, and some saying it never fully decomposes. And yet, the scientists assert these polymers derived from plastic bottles are biocompatible, and that, after eradicating the dangerous bacteria ‘disappear by biodegrading’. I ask Engler how this is possible, and she explains: “What we anticipate is that they will start out self-assembling together, and, what eventually will happen is that they will start to disassemble, much like when you lose at poker, you lose a chip at a time, and that will end up being excreted out because that is of low enough molecular weight to be excreted out through the body.”

The polymers derived from plastic bottles have displayed some very encouraging results in the lab: studies conducted by Singapore’s IBN showed the nanofibers eradicated more than 99.9 per cent of Candida albicans, a fungus causing the third most common blood stream infection in the United States; and the polymers were also found to be effective in experiments on mice with a common infection of C. albicans associated with contact lenses. Engler is quick to point out, however, that it’s still early days when it comes to the project: “Our results are promising at this point, but as with a lot of drugs out there, the results are promising at the early stages, but we don’t know what’s going to happen as we continue on.”

And in this case there’s the added complication that technology giant IBM is relatively new to the realm of bioengineering and nanotechnology (Engler herself admits: “I hadn’t heard IBM was working on this sort of thing until I was approached at a conference to come work here – my expression of disbelief was: ‘IBM works on what?!’). The department came about through the realisation that “many of the materials that are used in the semi-conductor industry are also the same materials that are used as biomaterials”, and has been working closely with IBN through its four years of existence. “We do a lot of the material and synthesis, and they help us with the biological testing”, Engler explains. And now, the researchers are seeking partners to help run the trials and bring the ninja polymers to market.

In the meantime, the small team of around 10 scientists has other projects on the go, of course – one focusing on “what we can do with the excess materials once we’ve broken the PET down, looking to build up a new polymer from it”. It’s still too soon to talk about the project, but Engler says: “Hopefully there’ll be some excitement coming out of that very soon – it’s guaranteed to be exciting.”

Watch this space.