TRPS has filled the unmet need for precise characterisation for a range of particle types. Given its ability to accurately and reproducibly resolve samples to a high level of resolution, Tunable Resistive Pulse Sensing (TRPS) lends itself to a wide range of applications across biological and pharmaceutical research and development. Whilst this is not inherently inferior in many circumstances, the actual diameter may be favoured by some regulatory bodies in the nanomedicine space. Finally, whilst TRPS measures actual diameter, DLS can only measure hydrodynamic radius. 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. 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. Unlike DLS, TRPS measurements are independent of the particle or dispersant’s optical properties, allowing you to confidently measure samples with heterogenous optical densities. TRPS enables high-resolution particle measurement (40 nm to > 11 µm), allowing a wide range of particle types to be characterised. With DLS, these subtle differences can easily be missed. 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. 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. The resulting intensity-weighted particle size distribution is then transformed into particle concentration distribution, using an equation which also takes into account other various factors including: the derived photon count rate from particle scattering, the derived photon count rate from a reference liquid, the instrument’s detection efficiency, and the optical properties of the particles and dispersant.įor 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. MADLS size measurements are obtained by analysing multiple scattering autocorrelation functions, usually recorded at three angles. Multi-Angle Dynamic Light Scattering (MADLS) is a variation of DLS which combines scattering information from multiple angles to deliver particle size distribution at a higher resolution than single-angle DLS. Particle concentration cannot be measured using DLS.
The magnitude of the scattered intensity is a function of several parameters including particle size therefore, by applying a scattering autocorrelation function and several assumptions, the average hydrodynamic diameter of particles in the sample can be calculated. Dynamic Light Scattering (DLS) involves applying a laser beam to the sample and monitoring fluctuations in the scattering intensity which results from the Brownian motion of the particles.
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