Tunable Resistive Pulse Sensing vs Dynamic Light Scattering

For those looking to gain real insights into the size and concentration, or size and zeta potential, of particles in their sample, Tunable Resistive Pulse Sensing (TRPS) is a far superior technique. Unlike Dynamic Light Scattering (DLS), which is an ensemble technique that measures the average intensity of light scattered by particles in a solution, TRPS is a single-particle analytical method and uses more direct measurements of physical characteristics. This allows you to detect subtle differences between subpopulations of particles in your sample – differences which may be critical indicators of sample stability, aggregation, or differences in drug loading efficiency. With DLS, these subtle differences can easily be missed.

TRPS enables high-resolution particle measurement (40 nm to > 11 µm), allowing a wide range of particle types to be characterised. Unlike DLS, TRPS measurements are independent of the particle or dispersant’s optical properties, allowing you to confidently measure samples with heterogenous optical densities. With DLS, larger particles tend to be overestimated, distorting the particle distribution and obscuring smaller particles due to the sextic dependence of light-scattering intensity.

The ensemble approach of DLS limits subpopulation identification; a recent study showed Multi-Angle Dynamic Light Scattering (MADLS) failing to identify subpopulations within quadrimodal samples, whereas TRPS could identify all four subpopulations. Finally, whilst TRPS measures actual diameter, DLS can only measure hydrodynamic radius. Whilst this is not inherently inferior in many circumstances, the actual diameter may be favoured by some regulatory bodies in the nanomedicine space.