The ability of TRPS technology to measure particle-by-particle offers a more comprehensive characterisation of virion/VLP preparations, by simultaneously quantifying key physical parameters with high accuracy and precision. TRPS determines virus/VLP concentration, size, and zeta potential by measuring the characteristics of a blockade created when particles pass through the nanopore.
Many relevant biological interactions between viral particles or with a cellular recipient might depend on their charge or zeta potential. Zeta potential is a measure of effective charge of a nanoparticle in a certain medium and it represents the colloidal stability of particle−particle and particle− medium interactions. The tendency of virus/VLP preparations to aggregate or remain in suspension depends on the zeta potential and may be subject to different short or long-term formulation stability studies and subsequent manufacturing optimisation approaches. The charge of viruses/VLPs can influence their cellular uptake efficiencies and cytotoxicity effects in recipient host cells. Thus, opportunities arise for charge-based smart design and modifications of virus/VLP epitopes to optimise infectivity rates in the context of therapeutics or vaccines.
The ability of TRPS to analyse heterogenous populations with high resolving power enables discriminating subpopulations of viruses within a sample when species exhibit even slight differences in diameters or zeta potentials. Very small changes in zeta potential or particle size of viruses/VLPs in response to the binding of an antibody or aptamer can be evaluated using TRPS, allowing identification and specific quantification of subpopulations effectively labelled, leading to a reliable assessment at different stages of any assay optimisation process, especially important in diagnostics development.