Nanoparticle tracking in aqueous solution

Abstract

Real-time observation of particles or bio-molecules can answer many fundamental questions like spatial temporal information in its natural environment. I have attempted to study the real time tracking of nanoparticles and corresponding Brownian motions using laser scanning confocal microscopy. The diffusion constant obtained from the Brownian motions of the recorded videos was used to determine the size of the particle using the Stokes-Einstein equation. The particle size was found to be in micrometer scale and substantially larger than the actual size of the nanoparticles (<20nm). The micrometer size, however, was in agreement with the measurement obtained from dynamic light scattering. This indicates that (i) particle-tracking is a promising tool in determining the behaviour of particles in solution, and (ii) for the nanoparticles in the current study exhibited extensive particle aggregation and caused complication in the data analysis. The future work can be focussed on obtaining a more homogeneous suspension of nanoparticles with no/minimal aggregation to deduce more reasonable information on the particle motion and structural information.