The Story of the Golden Orb

Materials made from proteins: the past and the future

There is a famous scene in the iconic 1967 film, the Graduate, where Dustin Hoffman plays Benjamin Braddock, a young man ready to embark on the great adventure of life. At a cocktail party, a friend of Ben’s parents, Mr. McGuire, pulls off the newly minted graduate to give him a word of advice. The advice is literally one word: PLASTICS.

Although the scene’s intention was supposedly to highlight Mr. McGuire’s outdated worldview, the old man turned out to be right. Though, to be more accurate, he should have said POLYMERS, the scientific term that encapsulates different classes of petroleum-based materials used to make everything from Tupperware to Teslas, from grocery bags to construction materials, and from nylon stockings to bulletproof vests.

The development of synthetic polymers kickstarted the unprecedented economic growth of the 20th century. But by the beginning of the 21st century, plastics have become one of our biggest problems. Plastics are polluting our oceans at an alarming rate: it is estimated that by 2050, there will be more plastic than fish in our oceans. It is time to turn things around and prove that old Mr. McGuire was indeed wrong.

Our plastic addiction

If we know of the negative impact of plastics, why is it so hard to give up our plastic addiction? For one, plastics are incredibly useful and versatile materials: they are light, cheap to make, stretchy and durable, they can be melted, poured, molded into every imaginable and unimaginable shape, and even recycled (although that’s a whole other can of worms). The problem is that the same properties that make plastics so useful—the fact that they cannot be dissolved by water or broken down in the environment—make them one of the biggest pollutants of the modern world.

Our love-hate relationship with these synthetic materials is evident in that “plastic” has become a synonym for cheap, artificial, and disposable materials. Many people lament the days when things used to be made from legacy materials, like leather, silk and wool or even horn and ivory, which arguably show superior performance. For example, leather can withstand heat and cold much better than its faux counterpart. It can stretch without losing integrity and also maintain the shape given to it. Similarly, silk is both warming and breathable, luxuriously soft and surprisingly strong.

Although these materials could not be more different from one another in terms of their properties, they actually have something in common—they are all made of the same kind of molecules: PROTEINS. Proteins are incredibly versatile functional materials. The big question is: could proteins replace synthetic polymers in the products we use every day and fulfill the needs of our growing world?

Unraveling the thread

If we zoom in to the molecular level, synthetic polymers and natural protein-based materials are kind of similar: they both consist of the same repeating molecular units. For example, polyethylene, the polymer that makes grocery bags and disposable water bottles, is a string of thousands of ethylene molecules—hence its name “poly” meaning “many” and “ethylene”, which is a short hydrocarbon derived from natural gas and petroleum. If you add a catalyst to ethylene, the tiny molecules get glued together into long strings (or somewhat branched chains).

It may sound surprising at first, but proteins are also polymers. However, instead of being made of the same molecule (like ethylene) or even two different molecules (like polyurethane), proteins are made of twenty different building blocks. This gives nature a lot of room for creativity when it comes to inventing materials. Some proteins are stiff like beams and others are stretchy like springs. No wonder the properties of natural polymers like leather and silk are so different from one another!

Take silk, for example. Silk is a natural fiber produced by domesticated silkworms. Two proteins make up silk: fibroin and sericin. Sericin is the sticky substance that helps glue together the cocoon, while fibroin is what we make silk cloth from. It is similar to keratin, the protein in our hair, except silk fibers are much thinner and longer: a single silk thread can stretch up to one kilometer. Fibroin molecular structure forms nanocrystals, which give silk its strength. These micro threads combine to form a prism-like structure, which gives silk a shimmering appearance.

Silk is an incredibly functional material: It can absorb up to 30% of its weight in moisture without feeling damp. But silk manufacturing is expensive and time-consuming, which makes this fabric not very scalable. For the past 4000 years, silk-producing technology has not changed fundamentally: it is still harvested by unwrapping the cocoons of silk caterpillars, brushing them and spinning into threads. In contrast, synthetic fibers are made directly from raw materials into their final form—no wonder textile manufacturers made the switch from silk to nylon so eagerly.

Science fiction meets technology

But what if I told you that there is a material even more incredible than silk? It’s spider silk, the same stuff that spiderwebs are made of. Spider silk fibers are as elastic as rubber and have a tensile strength comparable to that of steel. It’s several times tougher than either Nylon or Kevlar and at the same time, it’s incredibly light. Spider silk is also antimicrobial, hypoallergenic, biocompatible and completely biodegradable.

Unlike silkworms, spiders have not been domesticated, so we have not been able to take advantage of the unique properties of spider silk. Back in the early 1700s, a crazy French man by the name of Francois-Xavier Bon de Saint Hilaire, published a “Dissertation on the Spider”, a treatise in which he described the process of obtaining silk from common spiders. He backed up theory with practice by making a couple of pairs of stockings and gloves from spider silk.

Unfortunately, the enthusiasm for this invention disappeared with the inventor. No one had attempted growing thousands of spiders and spinning threads from their tiny eggs for almost two hundred years, until another crazy French man, a Jesuit priest, Fr Camboué, living in Madagascar decided to repeat the experiment with the local Golden Orb-weaver spider. He managed to make a canopy woven from golden spider silk, which was exhibited at the 1900 Paris Exposition.

The marriage of the old and the new

Among the eccentric people who have tried making spider silk fabric is Simon Peers, who succeeded in making the extraordinarily beautiful golden cape from the silk of Madagascar’s Golden Orb weaver spiders that was displayed at the Victoria and Albert Museum in London. He describes the effort of silking a million spiders, which took nearly 8 years, as a “Sisyphean challenge”. The result, however, is truly incredible—I encourage you to watch this short YouTube video that demonstrates the cape.

Like Peers and many before him, I have wondered: can we bring the superior performance of natural materials up to scale to make them as accessible as the plastics we use today? A few years ago, Korean scientists figured out how to produce spider silk in engineered microbes. Later, other researchers tweaked the structure of the protein so that it wouldn’t shrink in water as does actual spider silk, and created a company called Spiber that commercialized the engineered spider silk production process and made the first spider silk ski jacket to show off the new technology.

We live in a time when we are ready to graduate from synthetic, plastic materials and start thinking about the ways we will make materials in the future. Combining the wisdom of millions of years of evolution with the advances in manufacturing we have made in the 20th century and the emerging possibilities of AI-aided design—this marriage of the old, the newer, and the truly new—is the way of the future.