Three-Dimensional Automated Nanoparticle Tracking Using Mie Scattering (CAT#: STEM-ST-0083-YJL)

Introduction

Nanoparticles are becoming ubiquitous in many areas of biology and chemistry where they are finding a myriad of uses, including in arrays as chemosensing and biosensing platforms, as building blocks for more complicated structures, and individually as alternatives to fluorescent molecules and quantum dots as labels in bioanalysis. In colloidal systems, interactions of particles of the order of 100 nm to 1 mm control the behavioral characteristics, for instance the interaction of fat particles and proteins determine whether milk coagulates into cheese or yoghurt. In all of ¨ these applications, the capability to locate, track and identify the size of nanoparticles is important but it is not possible to resolve such particles in an optical microscope because their diameters are below the Rayleigh limit. For metallic nanoparticles, fluorescent-based techniques are viable but liable to photo-bleaching, so dark-fieldmicroscopy has become a popular way of observing their location and movement because their scattering cross-section is substantially larger than the particle.