Are nanoparticles safe? That is the question SINTEF (Stiftelsen for industriell og teknisk forskning, or the Foundation for Scientific and Industrial Research), a major Norwegian-based research organization—and producer of nanoparticles—aims to answer.
Nanoparticles are particles with a diameter between 1 and 100 nanometers. (A nanometer is one billionth of a meter.)
Andy Booth, SINTEF scientist and environmental chemist, is leading a project designed to find out how nanoparticles behave and if they are safe for organisms once they enter the marine environment. Initially, their toxicity to small organisms, such as crustaceans and animal plankton, will be studied, followed by their effect on cod larvae and other larger organisms.
Nanoparticles occur naturally. For example, ash contains nanoparticles, and not all of the millions of different types of nanoparticles are likely to be dangerous.
“[But] what is new is that we are now capable of designing nanoparticles with a wide range of different properties. Such particles can be different from those that already occur in nature, and they are intended to perform specific tasks at our command, so we do not know how they will behave in nature,” explained Booth in a press release.
“This could potentially—and I say ‘potentially’ because this topic is so new to science—indicate that these particles could be toxic under certain conditions. However, this depends on a number of factors, including their concentration and the combination of particles,” emphasizes Booth.
One of the biggest challenges faced by the 12-member team is finding suitable scientific methods to study the behavior of the tiny particles in nature, which act differently to normal particles.
“In the field of chemical analysis, we have standard tests that tell us whether or not a material is toxic. Today, there are no such tests for nanoparticles that are 100 percent accurate,” said Booth.
“These [nano]particles also behave differently in fresh and salt water. Finding methods that will enable us to study their behavior is essential.”
One method could involve adding fluorescent markers to the particles so they can be seen “glowing” among other particles in samples viewed under a spectroscopic camera.
“The big question now is to find out how high concentrations we need to test in order to be on the safe side. It is not worth taking chances with nature,” concludes Booth.
The applications of nanoparticles currently under development by SINTEF scientists include durable scratch-resistant paint for vehicles; a credit-card-size medical device for analyzing blood and other fluid samples, the so-called lab-on-a-chip; and nanocapsules, which are hollow nanoparticles that could be used to deliver drugs to specific sites inside the body.
Nanoparticles can be used to make capsules for delivering medicines to designated cells, so scientists need to make sure the particles they use can break down into harmless components that can be excreted from the body.
“These capsules are a plus because here we want the capsules to pass through the cell membrane and do their work locally. Other types of nanoparticles can pass the membrane and become a danger to the body. The risk of nanotechnology is that sometimes they are not supposed to pass, or that they accumulate in large quantities over a period of time, instead of disappearing,” said SINTEF researcher Ruth Schmidt, who is working on a cancer treatment using nanocapsules.
“We don’t use nanotubes or nanofibers, because we believe that they are less safe than particles,” she said.
The effect of carbon-based nanotubes and nanofibers on rat brain cells has been investigated by a team from the Department of Neuromedicine at the Norwegian University of Science and Technology led by Tore Syvertsen. They found that the rat cells were fairly sensitive to the nanoparticles, and that the size and shape of the particles was significant.
“This shows that there are good reasons for studying where the boundary between hazardous and nonhazardous nanotubes lies,” said Syvertsen in a press release. “Other studies of similar carbon fibers have shown that they can cause a type of lung cancer that is otherwise best known for being due to exposure to asbestos. Since this type of cancer takes a long time to develop, it is essential to test such materials before they come into widespread use.”
