Big questions about tiny particles

Understanding the effects of new products and technologies is increasingly important in our fast-paced world. By understanding the potential health impacts of new products, research scientist provide guidance on ways to use them safely, resulting in policies, regulations and guidelines that weigh risks and benefits of all kinds of innovations.

One big advance is the use of engineered nanomaterials. These substances are intentionally produced to be very small in size, as much as 10,000 times smaller than the diameter of a hair strand. This allows us to change the way the substance behaves, making it possible to use it in new ways. For example, titanium dioxide is a common ingredient found in sunscreen. Reducing the size of titanium dioxide particles removes the white film left behind on the skin by some sunscreens. Their smaller size also provides better protection against the harsh rays of the sun.

Silver is another product you might come across in its nanosized form. Engineered silver particles are added to gauze, dressings, and adhesive bandages because of the chemical element’s antibacterial properties, to help reduce the risk of infection. Some types of clothing, including socks, pillows and other bedding, also take advantage of the antibacterial property of silver for improving hygiene. No more nasty smells thanks to nanosized silver!

Because engineered nanomaterials have been increasingly incorporated into many products, it becomes vital to understand what happens when we are exposed to them. Since their tiny size makes it possible for nanomaterials to travel deeper into organs and tissues, we need to know how the body will respond to these materials.

Dr. Sabina Halappanavar is a Health Canada Research Scientist who investigates possible human health impacts of exposure to engineered nanomaterials, with a special focus on the respiratory system. Her work has also been instrumental in developing more effective tools that help reduce the use of animals in laboratory experiments.

Technology-enabled substances like nanomaterials call for rigorous and innovative testing methods that provide high quality data. Dr. Halappanavar’s laboratory uses a technique called lung organ culture, where a small piece of lung tissue is grown in a container, in parallel with techniques that allow her to record all molecular changes that occur in a cell after it is exposed to nanomaterials. She explains that “these advanced models of testing allow researchers to observe responses at the molecular and cellular level, in their original anatomical structure, outside the animal.” The data generated from such tools contribute to the screening of large number of nanomaterials to determine their impact on lung health, in a short time and with fewer animals.

Through its work, Dr. Halappanavar’s team at Health Canada is attracting international attention. She notes “because every new iteration of nanomaterial requires separate testing, assessment quickly becomes a monumental task”. In order to do her part, Dr. Halappanavar participates in initiatives led by international bodies such as the World Health Organisation (WHO) and the Organisation for Economic Co-operation and Development (OECD). She also partners with several international researchers to develop best practices for testing nanomaterials. She actively leverages international expertise, resources and tools to advance the state of science in this field and to inform the regulatory decision-making at Health Canada. In short, she contributes to making products safer for Canadians.


Let’s draw attention to the incredible work of women in science! This article is part of a month-long series celebrating women in science, from International Day of Women and Girls in Science (February 11) to International Women’s Day (March 8).