Taiwan Green Bulletin

Teenagers might well be able to solve some of the world’s trickiest problems. Do you remember the Dutch high-school student who came up with an idea to use giant booms to clean the oceans of vast mountains of plastic waste? Floppy-haired Boyan Slat’s invention will set sail in the next year ahead of schedule and despite some non-believers. We should all hope that his project, Ocean Cleanup, will clean up!

Taiwan has its own share of green-keen teens. Inspired by a study on jellyfish mucus, a team of senior high-school students from the Taipei American School (TAS) have come up with a way to trap nanoparticles from wastewater that could be used in treatment plants. Nanoparticles, extremely tiny particles (one step smaller than microplastics, which we have been hearing a lot about recently), are used in a wide range of everyday objects such as medicines, cosmetics and clothing, yet they pose a potentially toxic risk to the environment and human health. This November, the students are taking their idea to the iGEM competition, an international student throw down in the field of synthetic biology.

For the first edition of what will be a regular bi-weekly series, Green Bulletin interviewed 18-year-old Ashley Lin, policy head of the TAS iGEM team.


Credit: TAS iGEM team.

Ashley Lin, the TAS iGEM team's policy head.

Q: There’s been a lot of news about pollution from microplastics in the past few years – what’s the difference between micro and nanoparticles?

Ashley Lin: Microplastics and nanoparticles are different sizes: microplastics are 10-6 and nanoparticles are 10-9. Like nanoparticles, microplastics are used in a variety of consumer products, such as cosmetics. However, due to their larger size, microplastics actually have more limited use than nanoparticles.

Microplastic litter accumulation in the ocean damages marine foodchains, and research has shown that human consumption of microplastics can lead them to be trapped in the circulatory system. Yet because of their significantly smaller size, nanoparticles pose an even greater threat to humans and the environment. Although there has been no substantive research on nanoparticles' effects on the human body, some studies have shown that when inhaled, nano-sized TiO2 (titanium oxide) can cause pulmonary wall damage and lead to tumors in the human body. There is also the danger that nanoparticles can enter our bodies through means other than ingestion and inhalation, such as the possibility of nanoparticles permeating our skin.

Q: How did your team come up with the idea of trapping nanoparticles?

Lin: We initially focused on several ideas, such as using spider silk in medical applications and using enzymes to stop nicotine addiction. The team members voted and ultimately decided on the current topic: removing nanoparticle waste from wastewater treatment plants, as it has a strong prototype potential, is a novel approach to the water purification issue, and is also experimentally feasible. Most importantly, water safety is an issue critical to all of us, and with the rise of nanoparticle use in the last decade, we believe they pose great danger to water safety.

Q: What is the purpose of the project and how did you achieve your goal?

Lin: Our goal is to efficiently remove nanoparticles from wastewater systems to prevent major nanoparticle pollution. What makes this simple goal complex, however, is that nanoparticles “come in all shapes and sizes” (literally). This means approaches that exploit highly-specific properties of one type are inefficient. [So] we’ve devised a two-pronged approach.

Most engineered nanoparticles… have a “coating”… on the surface… and citrate is the most common [coating] used by industry. Exploiting this characteristic, we’ve designed a custom membrane protein that can bind to the citrate. Ideally, this will increase the size and weight of the target so that existing infrastructure designed to filter out bacteria in wastewater treatment plants can take over and filter out nanoparticles.

What about those not capped with citrate? We’ve devised a general approach that does not target specific characteristics of certain nanoparticles. We were originally inspired by a study that used jellyfish mucus to trap and purify gold nanoparticles. After preliminary testing and research, we’ve shown that our biofilms can also trap nanoparticles and pull them out of solution, similar to the jellyfish mucus.


Credit: TAS iGEM team.

The TAS iGEM competition team.

Q: What makes nanoparticles so interesting?

Lin: I'm interested in nanoparticles because it's fascinating to see how materials behave so differently at a nanoscale, and how electrical, optical, chemical, and magnetic properties change from the mass scale. Because of the ability of nanoparticles to have such diverse properties, the possibilities of applying nanoparticles to new uses is exciting and opens our imaginations.

Q: Taiwan recently announced it will expand its free plastic bag ban to 80,000 more stores next year in its bid to make the country plastic free in 10 years. What’s the situation for nanoparticles in Taiwan?

Lin: I know that the Taiwan Environmental Protection Administration has issued guidance on nanoparticles in utensils and medical devices, and has mandated the registration of nanomaterials into the management of chemical substances, but I am not aware of a nanoparticle-specific legislation directed at industry. Right now, nanoparticles are not removed from wastewater treatment plants, as the filtration isn't complex enough to filter out the nanoparticles. This is why the TAS iGEM team is devising a device to solve this issue.

Q: With microplastics the focus has been on banning them or getting brands to stop using them. Couldn’t we do this for nanoplastics? Is it better to ban them or try to trap them?

Lin: Sure, the government can try raising awareness about the dangers of nanoparticles and getting manufacturers to stop using them, but in order to have the power to do this, the legal empirices about banning nanoparticles need to be sound, and right now no legislation characterizes nanoparticles as a separate substance from its bulk material, which prevents agencies from acquiring regulatory power.

If you are interested in the nanoparticle project, more information can be found on the team’s website

All that’s left for us to say is — good luck in the competition!