An ultimate goal in the biomimetic community (the science that tries to mimic nature to solve human problems), is to synthetically make spiders silk, without the spiders. So what's stopping scientists doing this? Farming spiders to make silk is an arduous process. Best case scenario you could get ~ 100 ft of spiders silk in one session, but then the spider would need time to feed and regenerate it's silk reserves. Options? Genetically make a monstrous spider to harvest huge amounts of silk or breed billions of spiders to do the job, or...
Spiders' silk, like many biological materials, are composed of a hierarchical structure. In a simple sense, spiders' silk is a spun protein fibre. It has long been known that the size of the protein units within the silk correlates with the strength of the silk; larger proteins generally means stronger silk. However, natural silks have a limit in the size of the proteins that they use; for whatever evolutionary reason this has happened...
For human purposes, it was proposed to mutate the spiders' DNA, insert it in to bacteria (poor things) and force those bacteria to make the desired proteins (this actually happens routinely in a biological lab). However, bacteria (I don't blame them!) cannot make such large proteins; it's been a running problem in biochemistry for some time. What the scientists did, therefore, was insert a DNA segment that would chemically fuse two smaller silk proteins to form a single large protein unit. To their joy and adulation, they succeeded. With protein in hand (or actually 'in dish') they spun these synthetic proteins in to a silk and found that they performed as well as natural silk, in terms of tensile strength, toughness, elastic modulus and extensibility!
Being able to make silk without a spider is a really promising prospect. Now that scientists can modify the protein size (and composition) within the fibre and use bacteria to produce the desired silk it leads to a whole host of possibilities in making future materials with enhanced properties.
The image above was taken from a Business Insider video over here.
An interview of those scientists can be found on Science Daily.