The quartz crystal microbalance with dissipation monitoring (QCM-D) is a useful technique for evaluating the deposition behavior of engineered nanoparticles (ENPs) on model environmental surfaces such as SiO2, Fe2O3 and Al2O3. As particles deposit onto the QCM sensor, an increase in mass on the surface results in a measurable decrease in the crystal’s resonance frequency in accordance with the Sauerbrey model. QCM-D can thus be used to evaluate ENP deposition kinetics onto model aquifer grain surfaces over a broad range of environmentally relevant conditions. Furthermore, monitoring of dissipative energy losses induced by the deposited ENPs can provide information on their coupling with the surface as well as their size and surface orientation. Although QCM-D has been used to gain insight into the potential transport behavior of different ENPs in natural aquatic environments, a number of caveats exist in the interpretation of QCM-D measurements. For instance, positive frequency shifts have been reported which are counterintuitive to the principle of QCM-D as a mass sensor. In particular, the interpretation of QCM-D measurements for aggregated ENP systems has proven to be challenging. Consideration of the “coupled-resonance theory” for appropriate interpretation of such measurements will be discussed. We have also shown how QCM-D can be used to directly detect with great sensitivity the interactions of ENPs with supported lipid bilayers as model cell membranes and resulting bilayer disruption, which makes it a complementary tool for nanotoxicity studies. Taken together, this body of work demonstrates some of the potential applications and limitations of QCM-D in environmental nanoscience.
Nathalie Tufenkji received her Bachelor’s degree in Chemical Engineering from McGill University in 1999 and went on to Yale, where she earned the M.Sc. (2001) and Ph.D. (2005) degrees in Chemical and Environmental Engineering. Dr. Tufenkji returned to her alma mater as Assistant Professor in 2005 and is presently Associate Professor in the Department of Chemical Engineering at McGill where she holds the Canada Research Chair in Biocolloids and Surfaces. Dr. Tufenkji works in the area of (bio)colloid-surface interactions with applications in protection of water resources, engineering of biosensors and antimicrobial materials, and development of safe nanotechnology. Dr. Tufenkji also serves as Associate Director of the Brace Center for Water Resources Management at McGill and on the editorial boards of Environmental Science and Technology, Water Research, Colloids and Surfaces B, Advances in Colloid and Interface Science and Frontiers in Chemical Engineering.