That shrinking feeling

2018 saw the return of Ant-Man to the big-screen, leading to more size-changing shenanigans with the superhero. However, it seems that shrinking may be moving from science-fiction to science fact – a team at MIT, led by Professor Edward Boyden, have invented a new technique to shrink objects to the nanoscale, and it could have some fascinating implications for a whole variety of fields.

Boyden’s team adapted a technique developed a few years ago for high-resolution imaging of brain tissue – known as expansion microscopy, it involves embedding tissue into a hydrogel (the kind of absorbent material you find in diapers) and then expanding it, which allowed for high-res and 3D images with a regular microscope. They realised that the process could be reversed, creating an item embedded in an expanded hydrogel and then shrinking it down to the nanoscale.

A team at MIT have invented a new technique to shrink objects to the nanoscale 

The hydrogel (specifically, polyacrylate) functions as a scaffold of sorts, to which the team attached fluorescein molecules (which act as anchors) – the hydrogel is bathed in a solution of these molecules, which are activated by laser light. On this frame, other types of molecules can be attached, shaping whatever structure the team want to build.

When the structure is assembled, it can all be shrunk by adding an acid – it blocks the negative charges in the polyacrylate gel so they no longer repel each other, causing the gel to contract. The objects can shrink ten-fold in each dimension, for an overall 1000-fold reduction in volume – the low-density scaffold makes for a dense solid when it is shrunk. The most exciting thing is that there’s no need for any special equipment – most research labs are already stocked with the equipment required for this process, and Boyden hopes it could yield big results: “Democratising nanofabrication could open up frontiers we can’t yet imagine.”

When the structure is assembled, it can all be shrunk by adding an acid 

Now, this science is very impressive, with many potential future uses, from medicine to robotics. However, it’s not strictly shrinking as we typically imagine it, in films like Ant–Man and Downsizing. Could it be possible to truly shrink something, or increase its size? Well, in 2003, Michael C. LaBarbera at the University of Chicago tackled that very question, in a paper called The Biology of B-Movie Monsters, which discussed the science of ‘scaling’, or how size affects biology.

Many of our biological functions, such as oxygen extraction in the lungs and nutrient absorption, are dependent on proportionality, and upsetting the mathematical layout of the body would be problematic at any size. Imagine a man shrinking to the size of an ant – his mass would decrease significantly more than his surface area, which would make it very difficult to maintain body heat. The ant-man would have to eat his own weight daily, without sleep, to supply his body with enough fuel (in much the same way as the hummingbird). Ant-Man’s costume designers did try to address some of the science – one of the limitations placed on the character was that he had to be fully contained within his suit when shrunk, or the molecules in the air would be too big for his lungs.

Imagine a man shrinking to the size of an ant – his mass would decrease significantly more than his surface area 

There are practical issues to being small too, according to the team behind Downsizing. Matt Damon’s character in the film works at a call centre, but his tiny voice would be too high-pitched to answer calls from regularly-sized people. He’d likely get swept away in a strong gust of wind and, without a safety net around his miniature colony, there’s a huge risk that a predator (a cat or rat) could kill and eat them.

However, there could be benefits – NYU bioethicist S. Matthew Liao suggested that shrinking people could help mitigate the effects of climate change. 100 years ago, humans were roughly 15cm shorter, and the mass reduction this would create could offset climate change effects. This type of shrinking is also realistically possible – there are around 500 genes in the body that code height, and biologists could engineer children to be shorter (if they turned a blind eye to the obvious ethical questions this would throw up, that is).

There are practical issues to being small too, according to the team behind Downsizing

Some of these forms of shrinking may be a long way off, but the work carried out by Boyden and his team will likely find some incredible applications in the future. Who knows – give it a couple of years, and maybe we could all be Ant-Man!