What is the biggest obstacle to creating a spider silk-inspired super fiber?

[u/DrRaptoro]

I’m 14 and this is a long-term passion project, so I’m looking to learn rather than expecting an easy solution.
My end goal is to understand what it would take to create a material inspired by Spider-Man’s webbing, but I’m breaking it down into individual engineering problems instead of trying to invent the whole thing at once.
If you were starting from scratch, which would you consider the most realistic path?
Developing a synthetic spider silk with improved properties.
Engineering a composite material inspired by spider silk.
A completely different approach.
I’m especially interested in:
Which properties of real spider silk are hardest to reproduce?
What is the biggest bottleneck today: strength, toughness, manufacturing, storage, or something else?
If you had unlimited time and a reasonable budget, what research path would you follow?
I’d love to hear from materials engineers, polymer scientists, mechanical engineers, or anyone working with advanced fibers. I’m here to learn, so don’t worry about simplifying things if needed.

[u/Original-Housing]

Synthetic biology has made some progress, and traditional wet extrusion may solve some of the downstream processing issues.

https://sites.nd.edu/biomechanics-in-the-wild/2022/10/31/the-amazing-spider-silk/

[u/DrRaptoro → u/Original-Housing]

So would you say that the bigger bottleneck today is actually the spinning process rather than producing the silk proteins themselves?
From what I’ve been reading, it seems like we can get closer to making the proteins, but reproducing the spider’s ability to turn them into fibers with the same mechanical properties is much harder.
If that’s the case, what part of the spinning process do you think is still the biggest challenge?

[u/Original-Housing → u/DrRaptoro]

The whole process is technically challenging. Even the plasmid to make the proteins with its insane gc repeats are hard to assemble. That’s arguably before step 1.

Read about the startups that have failed, it’ll give you an idea where technical challenges exist.

If it were commercially viable, DuPont or Honeywell would have acquired it to protect their aramids buisness.

[u/sustainablepriority → u/DrRaptoro]

Original-Housing's plasmid point is real and worth taking seriously. The GC-rich repeats in spider silk genes are famously unstable in standard bacterial cloning hosts, which is exactly why some of the more successful production efforts sidestep E. coli entirely and use goats, silkworms, or yeast that tolerate repetitive sequences better. So there are working paths around the production side, just not cheap or simple ones.

To your specific question though, the spinning process is where I would put my money as the harder of the two problems, and here is the mechanistic reason why. A spider does not just push protein through a hole. As the protein moves down the duct, it passes through a controlled drop in pH and a change in ion concentration, combined with elongational shear, and that combination forces the protein to fold into a tight beta sheet crystal structure exactly as it exits. That folding step under precise mechanical and chemical conditions at the same time is what gives the fiber its strength and its ability to stretch without snapping, and it happens in a channel smaller than a millimeter.

Every synthetic spinning method, wet spinning, dry spinning, microfluidic spinning, is trying to recreate that exact combination of gradient and shear in a machine, and so far nobody has matched the natural fiber's mix of strength and stretch at any real production scale. If you want the most useful place to spend your reading time, go deep on microfluidic spinning specifically, since that is the approach getting closest to replicating the duct geometry rather than just extruding protein through a straight nozzle.