Spider-Man's Web Shooter (original) (raw)

I have to admit that my favorite superhero as a kid, and still today, is Spider-Man (and yes, that’s the correct spelling). There are a number of narrative reasons for this that I grew to appreciate more as I aged. First, Spider-Man is in the sweet spot of super abilities – he is strong, fast, agile, and has “spidey senses”. But he is not boringly invulnerable like Superman. He doesn’t brute force his way to solving situations. You don’t have to retcon questions like – if Ironman has the technology to produce immense energy, why doesn’t he just make it available to the world? He would save more lives that way.

But of course the coolest aspect of Spider-Man is his webslinging. This allows him to fly through the city, and to tie-up villains for the police to collect. This is also one aspect of the Spider-Man story that I thought was a bit contrived (even for the superhero genre where being bitten by a radioactive spider gives you super powers). In science fiction you generally get one gimmie – the author is allowed to make up just one fantastical fact to use as a cornerstone of their story. But they should not introduce multiple such gimmies. It breaks the unwritten contract between author and reader.

With Spider-Man, the one gimmie is the whole radioactive spider thing. That’s the one thing we are being asked to just accept and not question. I do like how more modern versions of the story changed that to genetic engineering – still fantastical, but way more plausible than radioactivity. I also liked that in the Tobey Maguire Spider-Man his webbing was part of the genetic engineering, and he produced the spider silk himself and extruded it from spinners in his wrists. For other versions we are asked to accept a double-gimmie – first, the whole spider thing, and second that Peter Parker also happens to be such a genius that he invented practically overnight something that scientists have been unable to do in decades, mimic the spider silk-spinning of spiders. Spider-Man was created in 1962, and here we are more than 60 years later and this remains an intractable problem of material science.

Or is it?

OK, we are not there quite yet, but scientists have made a significant advance in artificially creating strands of silk. The problem has always been spinning the silk into threads. We can genetically engineer animals to produce spider silk, but it comes out as a glob. Spiders, however, are able to keep their silk a liquid, and then extrude it from their spinnerets as threads with variable properties, such as stickiness. We really want to be able to do this artificially and at scale because spider silk is really strong – depending on what type of strength you are talking about, spider silk can be as strong or stronger than steel. When you hear this statistic, however, that often is referring to specific strength, because spider silk is much lighter than steel, it is stronger per unit weight than steel. In any case – it’s strong.

Perhaps a better comparison is Kevlar. Spider silk has several advantages over this modern material – it is more resilient, flexible, and in some cases tougher. But we are still not close to spinning spider-silk bullet-proof vests.

The current study has a title that does not betray its possible significance – Dynamic Adhesive Fibers for Remote Capturing of Objects. That’s a technical way of saying – you can shoot freaking spider webs. What the researchers found is that if you take a liquid silk from B. mori, which is a domestic silk moth, and combine it with a solvent like alcohol or (as in this case) acetone, it will become a semi-solid hydrogel. But the process takes hours. You can’t have your villain waiting around for hours for the webbing to solidify. But, if you also add dopamine to the mix, the dopamine helps draw water away from the silk quickly, and the solidification process becomes almost instant. Shoot this combination as a stream and the acetone evaporates in the air while the dopamine draws away the water and you have -an instant sticky string of silk. You can literally shoot this at a object at range and then pick it up. The silk will stick to the object.

This is a massive advance, figuring out a key component to the process. Spiders and silk-producing insects also use dopamine in the process. Spiders generally don’t shoot their webs. They adhere it to an anchor and then draw it out. So in a way they have done spiders one better. But the real goal is making artificial silk that can then be made into fibers that can then be made into stuff.

Now, the main limiting factor here – spider silk is still about 1000 times stronger than the resulting silk in this study. It’s strong and sticky enough to pick up small objects, but it’s not going to replace Kevlar. But the authors point out – the properties of this silk are “tunable”. They write:

“Furthermore, the possibility of tuning these properties is demonstrated by adding chitosan (Ch) and borate ions (BB), leading to remarkable mechanical and adhesive performances up to 107 MPa and 280 kPa, respectively, which allows the retrieval of objects from the ejected structure. This process can be finely tuned to achieve a controlled fabrication of instantaneously formed adhesive hydrogel fibers for manifold applications, mimicking living organisms’ ability to eject tunable adhesive functional threads.”

Spider silk has a tensile strength of about 1 GPa, so that is still 100 times this silk. Of course, they are just getting started. The hope is that further research will reveal formulas for tuning the properties of this silk to make it super strong, or have whatever other properties we need. I don’t want to trivialize this. As I have frequently pointed out – when scientists say “all we have to do is” they really mean “there is a huge problem we cannot currently fix, and may never be able to fix.”

It’s possible this method of spinning silk fibers may end up being little more than a laboratory curiosity, or may have a few niche applications at best. It is also possible this is the beginning of the next plastic or carbon fibers. Probably we will end up somewhere in between. But I am hopeful. There is a reason material scientists have been trying to crack the spider silk puzzle for decades – because the potential is huge. This really is an amazing material with incredible potential.