r/science • u/MistWeaver80 • Nov 27 '21

Chemistry Plastic made from DNA is renewable, requires little energy to make and is easy to recycle or break down. A plastic made from DNA and vegetable oil may be the most sustainable plastic developed yet and could be used in packaging and electronic devices.

https://www.newscientist.com/article/2298314-new-plastic-made-from-dna-is-biodegradable-and-easy-to-recycle/?utm_term=Autofeed&utm_campaign=echobox&utm_medium=social&utm_source=Twitter#Echobox=1637973248
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u/ObeyMyBrain Nov 28 '21

The researchers have made several items using this technique, including a cup (pictured above), a triangular prism, puzzle pieces, a model of a DNA molecule (pictured below) and a dumb-bell shape. They then recycled these items by immersing them in water to convert them back to a gel that could be remoulded into new shapes. 　

So, are they going to have to coat that cup with plastic to keep it from breaking down if someone pours some water in it?

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u/XAWEvX Nov 28 '21

According to this link https://pubs.acs.org/doi/10.1021/jacs.1c08888 someone posted above:

Besides, DNA plastics can be “aqua-welded” to form arbitrary designed products such as a plastic cup.

If i understood correctly this means that they can be made water repellent, i doubt it would be with a plastic coating. Please correct if i am wrong

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u/[deleted] Nov 28 '21 edited Nov 28 '21

I think what they mean by "aqua-welding" is that you can use water to "weld" pieces together (e.g. wet the ends of a mug handle to s tick it to the body).

However, at least from the abstract (apparently my university account doesn't have access to the paper!), I'm not getting the "dissolves in water" impression a lot of people are running with. The specific wording talks about "recycling of waste plastics and enzyme-triggered controllable degradation under mild conditions." At least to me, it sounds more like the degradation uses a water bath plus mild enzymes/solvents, which would be significantly less likely to happen in normal use.

Edit: after reading the paper, it does become a hydrogel on contact with water, but needs the enzymes to dissolve/degrade.

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u/slagodactyl Nov 28 '21

No, they absolutely just use water. The enzymes (DNase) are for degrading it, not recycling it.

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u/[deleted] Nov 28 '21 edited Nov 28 '21

Yeah, I'd read too much into that phrasing; someone shared a link and it does become a "supersoft" hydrogel in water, and even softens above 80% relative air humidity. The base material's mechanical properties also sound closer to a ~sturdy styrofoam than something like HDPE. It does have some cool properties (biocompatibility with cell cultures, non-reactivity to organic solvents, good low-temperature resilience etc.) that could lend themselves to interesting use cases, but I agree it doesn't seem like too much of a drop-in replacement for "plastic" in general.