We hear a lot about the impact of plastic, but the truth is, the material is good at what it was made for. It’s cheap to manufacture, at about 1 cent per bag. It’s durable enough to withstand heat and cold, which makes it the perfect container to store everything from food to electronics. It even replaced animal-derived products like combs made of ivory for the mass market in the early 1900s.
Sadly though, plastic’s been too successful at its job. It’s cheaper to make new plastic than it is to recycle it. And since plastic can withstand high temperatures and doesn’t break down easily in water, it can take centuries to decompose. All of this adds up to plastic waste, which is destructive for the environment. A part of the problem here is even when the material finally does break down, it’s often not completely gone.
Microplastics are small plastic particles that stick around and have worked their way into the hardest places to reach on earth, including the top of Mount Everest and the bottom of the ocean. They’ve even been found in our blood, which is worrying because we don’t fully understand their long-term impact. However, similar to plastic, microplastics do have their uses.
Microplastics are used in products like pills, vitamins, or pesticides to keep them from mixing or breaking down until the time is right. They’re a necessity for manufacturers—but similar to ivory in the 1900s, we need to find a new substance that’s more sustainable. Recently, an MIT lab did just that.
Using silk capsules, MIT postdoc Muchun Liu was able to simulate the same slow-release solution that makes microplastics so successful. In fact, the silk capsules showed even better results than the microplastics they’re intended to replace when tested on crops.
So how realistic is it that we use silk in the future instead of microplastics? You may think of silk as a refined, expensive material that’s difficult to get your hands on. That’s because it is—when it’s being used for clothing. Luckily the quality of silk needed to replace intentionally-added microplastics is a lot lower and easier to get ahold off. The study also used existing technologies in manufacturing plants to create silk capsules, meaning it should be easy to implement.
Best of all, silk is nontoxic and breaks down organically in the body. It’s less harmful to humans and easier on the environment. And it’s estimated that 15% of microplastics in the environment come from intentionally-added use cases. While replacing them with silk won’t solve the problem, it will make a large dent in it.