The nano-police (Day 102)

Geoffrey Bothun

Geoffrey Bothun – chemical engineer looking at the implications of nanotechnology

In the UK, we’ve been tracking public attitudes to science since 1998.

Some of the central questions in the Public Attitudes to Science survey, by ipsos MORI, is to measure opinions towards ‘pace of change’, how much science is ‘valued’ and ‘trust’.

I’ll be exploring the results of the 2014 survey in more detail in tomorrow’s blog, but today I wanted to look at the issue of trust in relation to nanotechnology.

Some fields of science are more difficult to ‘police’ than others. This is certainly the case for nanotechnology – the creation of materials or processes at the nano-scale – which has attracted concerns about environmental risks that may not become apparent until decades later.

It’s the type of scenario which is pivotal to the notion of trust – get it wrong and public confidence as well as reputation and research funding come under threat.

The good news is that chemical engineers are trying to identify potential hazards before new nanotechnology products are in widespread use.

“Too often in the past we don’t know whether something will become a risk until it’s too late and it’s already out there,” says Geoffrey Bothun, an associate professor of chemical engineering at the University of Rhode Island.

He says: “Rather than create products with nanomaterials in them and simply releasing them into the marketplace, the field wants to get a better handle on what sort of environmental or safety risks are associated with these materials.”

Nanotechnology offers the potential for many new applications in medicine, electronics, energy and biomaterials but, like any new technology, it also raises concerns about possible toxicity to humans and the environment from long-term exposure.

iron oxide nanoparticle

Working at the nano level – a transmission electron microscopy image of an iron oxide nanoparticle (black) binding to an oppositely charged model cell membrane (phospholipid bilayer).  Credit: Geoff Bothun, University of Rhode Island

“There is a lot of excitement over what nanotechnology can do for job creation, new product development and better materials,” Bothun says. “It’s thought to be the new industrial revolution. But scientists, engineers and policy makers want to get ahead of the game and guide the design of the best materials with the least environmental impact.”

Geoff is currently working on a project to study how engineered nanoparticles bind to cell membranes, and the impact of the process on the membrane itself.

“We don’t know enough about how these physical interactions are taking place, and to what degree they contribute to toxicity,” he says. “Nanoparticles can and do inhibit or kill cells. In some cases, that’s what they are supposed to do. For example, there are a lot of natural antimicrobial molecules that bind to a membrane, disrupt it and break holes, leading to cell death.”

Nanoparticles exist in many products that come into close contact with humans, among them, clothing, medicine, cosmetics and sunscreen.

“Silver nanoparticles, for example, are in hunting gear and athletic clothing and act almost like an antibiotic,” Geoff Bothun says. “They kill bacteria that cause stinkiness largely by releasing silver ions. We’re exposed to this silver all the time, but whether or not it is dangerous is somewhat unknown.”

His research goal is to learn enough about what happens in nanoparticle-membrane interactions to allow experts to use this information in predicting whether the particles will prove toxic. “If we understand the mechanisms behind how these particles stick to cells, that should help us design particles that could selectively bind to, for example, bacteria and not human cells,” he says.

Geoff and his team use transmission electron microscopy (TEM) to study synthetic bacterial cell membranes they create and then expose to different types of nanoparticles.

“We can change the membrane composition, and nanoparticle type and composition and size,” he says. “We’ve got a lot of variables we can play with on both sides. With TEM we can directly image nanoparticle membrane binding and changes that occur in the membrane as a result of this binding.”

They already have determined that nanoparticles can behave like proteins, “meaning that we can use some of our existing knowledge and technologies on protein interactions to help understand and predict nanoparticle interactions,” he says. “For example, there are cases where hydrophobic (water hating) nanoparticles can change cell membrane structure similar to hydrophobic proteins.”

In the excitement of progress it is a comforting feeling to know that chemical engineers like Geoff Bothun, and others, are casting their watchful expertise for a safer technological future.

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