The detailed interactions of particles with mineral and biological surfaces in aqueous environments determine their ultimate fate and effect. This includes sorption and transport properties as well as toxicity and bioaccumulation. Here we use total internal reflection microscopy (TIRM), which applies state-of-the-art evanescent wave scattering and video microscopy techniques, to track in real time and space different engineered particles (silica and gold) in solution. Quantitative analysis allows us to determine the contribution of forces acting between a particle and a surface, which helps us to calculate important variables such as mean squared displacements, diffusion coefficients, particle size, and their stability over a range of solution conditions (i.e., pH and ionic strength). Findings so far include a better understanding of the silica-water interface and shedding new light on how rod-shaped particles interact with mineral surfaces present in porous media, and with biological surfaces, the latter including phospholipid membranes.

Quantitative analysis of particle-surface interactions in aqueous environments using total internal reflection microscopy

245th National Meeting (2013)

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