Spintex: Sustainable Materials Powered by 300 Million Years of R&D

Friends and labmates who trained together in the Oxford University silk group, Alex Greenhalgh and Dr. Martin Frydrych are tackling climate change one silk shirt at a time.  From their lab in Oxford, Alex answered some of my most pressing questions around the environmental damage fashion manufacturing is inflicting on our planet, Spintex’s unique take on a material that’s been used for millennia, and how a 300 million year-old technology can be new again.

[Interview has been edited for length, but not the British spellings.]

Pae Wu: First things first, how do you pronounce Greenhalgh?  

Alex Greenhalgh: Green-hal-sh, very soft on the s. But everyone has their own idea on how to pronounce it!

PW: Silk seems to be all the rage, but Spintex is coming at this in a totally different way than other venture-backed start-ups in the silk game.  What’s the key difference and what are the implications? 

AG: I think there are really three aspects to our approach which set us apart. Firstly, we produce a feedstock which has the key attribute of a natural silk, ‘shear-sensitivity’, which means it can transform from a liquid to a solid, just from a physical force, such as rubbing your hands together. . .if you pull it in the right way, the nanofibrils inside the solution start to orientate in one direction and form bonds between themselves, and you get a fibre

Crucially, we can produce this feedstock without bioreactors, which although it is an impressive technology, has seemingly struggled to replicate the size and complexity of the silk protein. This reduces our costs dramatically, whilst also allowing for a completely different form of spinning machine. 

Our spinning machines . . . instead rel[y] on the liquid to solid transition from force, meaning that the feedstock is actually self-assembling into the fibre. This is a direct mimicry of the spider’s approach, and is what gives us our impressive energy savings and material performance.

PW: Energy savings – I like the sound of that.   

AG: Compared to the traditional silk process that relies on heating huge vats of water and caustic chemicals to boiling temperatures to reel the silk from the cocoons, we can expect to produce our fibres with at least 50% energy savings, by removing the need for any heat inputs, which represent the vast majority of silk’s impact. I’m expecting once we run the numbers further, the energy reduction will be even greater, due to removing several of the more environmentally damaging chemicals from the traditional process, and an expected decrease by 100x in water consumption.

Even compared to other alternative silks, we expect to see a good reduction in energy requirements, as bioreactors commonly have to run above room temperature for their microbes, and require protein purification and freeze drying steps that are very high energy input.

PW: How will Spintex scale-up and disrupt the silk industry? 

AG: Our scaleup is somewhat easier to achieve than might be expected for a biotech company. We don’t need to invest heavily in large bioreactors, which are a serious drain in capital and very costly to run 24/7. Furthermore our consumables are all very cost-effective, and can be mostly sourced renewably

Our scaleup mostly comes from increasing the quantity of our feedstock [using] readily available machinery and automation, and increasing the throughput of our spinning process [by running] more [of our low-cost] spinning machines . . . in parallel.

Spintex spinning silk (say it fast 3 times)

PW: You say this is backed by millions of years of R&D – how’s that?  

AG: Silk first evolved in spiders around 300 million years ago, and . . . the versatility that silk provides to the spider . . . orb web, cobweb, natural diving bell[s], parachute[s] for young spiders to travel immense distances, demonstrates [its] value and usefulness.  

Interestingly, the approach to producing fibres through a low-energy spinning, is so effective that . . . it has evolved independently multiple times, in multiple arthropods, including bees and glowworms, arachnids and even a mollusc species. 

However when we look specifically at material properties, particularly toughness which is the combination of the strength and stretch of a material, spider silk reigns supreme. Although the underlying feedstock between species share many characteristics and attributes, it is the process that a spider uses to spin that seems to be critical to the performance. This is why we looked to spiders as our template for our spinning machinery.  

PW: Why is alternative silk such an appealing planetary health play?  

AG: The drive to reduce costs of clothing has seen many synthetic materials used, which we now know can have real impact, first in the energy or resources for their creation, to microplastics produced during washing, to problems with end-of-life

PW: Earlier, you described the immense energy and environmental cost involved in traditional silk production, too. 

AG: That’s right, it doesn’t mean natural materials are inherently better.  Traditional silk . . . doesn’t suffer from microshedding and can biodegrade, [but] takes a huge amount of energy for its production. The huge vats of boiling water . . . represent 50% of the total energy in silk’s production, and is the primary source of its large CO2 emissions. 

So even when using a natural product, we can’t seem to avoid having a negative impact on the environment. I think this is why alternative options, and new, sustainable technologies are so desirable, and really tackle some strong pain points for the industry.

PW: During IndieBio you’ve made some great progress with customers – what have been the highlights in customer development?  Any unexpected learnings? 

AG: For me, the real highlight has been the industry’s willingness to support innovation through a variety of means, including providing market and industry data, to supporting testing projects. I’ve been really impressed by the genuine commitment from them in seeing new developments that tackle sustainability issues in fashion, and even in other markets, where environmental issues are increasingly being taken very seriously. We’ve seen potential for collaborations and projects together, with real commitments for working together, beyond even LOIs.

An unexpected lesson for us, was not every value proposition is actually valuable for your customers. For example, we demonstrated some new dyeing possibilities using our fibres, that we thought would be exciting for reducing the environmental impact dyeing has. But most of our customers print directly onto the woven fabric, so they had no need for this!

PW: Elephant in the room, can folks test Spintex’s fibers?  

AG: From the very start we knew that the performance of our fibres would be critical. You can’t easily supplant an existing material, if you have grossly inferior qualities. So much time was spent on perfecting the feedstock and spinning processes to produce a material that can at least match a traditional silk. And what we found is that through our process, we can actually improve some properties, particularly toughness, to levels not seen in traditional silks, but in spider silks. 

We have had quite some interest in testing the fibres, particularly from performance and advanced material companies, which we have been happy to supply. The results closely matched our own testing, clearly showed the potential for the technology, giving unique possibilities in natural fibre textile spinning. These discussions are ongoing, but so far the reactions have all been positive. 

PW: What inspired you to start Spintex? 

AG: I’ve always loved science, but increasingly I found myself wanting to see research turn into an actual solution, that changes something, rather than just being an interesting footnote in an academic paper. With our work, we saw a real opportunity to provide a tangible benefit to the world. I’m especially excited about the possibility of reducing CO2 production in fashion, as the COVID pandemic has shown, even with personal changes to travel and working, we can only drop emissions by a fraction of what is needed to prevent devastating climate change. Manufacturing and the power generated for it are still by far some of the largest producers, so it’s crucial we start moving towards low energy methods for manufacture of the materials we need.

PW: What’s your biggest lesson from spinning (ahem) up Spintex during a global pandemic? 

AG: You never have enough of everything, so stock up! But also that tough times can be stressful and unpredictable, but if you keep pushing ahead you can weather nearly any storm.

PW: Finally, let’s play a little word association: What’s the first thing that comes to mind when you hear the term “butt rope”? 

AG: For me it’s a birthday card that I have received many many times from friends and family.  

Check out Spintex at IndieBio’s (virtual) Demo Day on 28 October!  Register here for the two-day event (27-28 October 2020).   

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