(13d) Orthogonal Methods Are Critical for Characterizing Nanoscale Colloids

Industries from food to healthcare are increasingly reliant on nanoparticle-mediated product enhancements. Instabilities in these colloidal systems cause critical performance failures and even fatal consequences in life science applications, and so accurate particle quantification is important.

While technologies for characterizing micron-sized particles are ubiquitous, most rely on optical particle detection approaches that fail in the nanoscale regime for fundamental physical reasons. But because these failures manifest in subtle and often sample-dependent ways, assessing the reliability of a given method to deliver accurate results can be difficult.

Measurement examples of a variety of colloidal materials are presented that reveal important limitations in the nanoscale regime of commonly used particle characterization technologies such as Dynamic Light Scattering (DLS) and Nanoparticle Tracking Analysis (NTA). The value provided by orthogonal measurements of these samples is demonstrated using an emerging microfluidic implementation of Resistive Pulse Sensing (aka. the Coulter principle), an electrical method.