Evaluation of zeta potential of nanomaterials by electrophoretic light scattering: Fast field reversal versus Slow field reversal modes.

Zeta potential of nanomaterials designed to be used in nanomedicine is an important parameter to evaluate as it influences in vivo behaviour hence biological activity, efficacy and safety. As mentioned by the International Organization for Standardization (ISO), electrophoretic light scattering is a relevant method for evaluating zeta potential. The present work aimed to validate a new protocol based on the application of Fast Field Reversal mode and to explore its scope with nanomaterials investigated as nanomedicines. Its scope was then compared with that of an already validated protocol which uses both Fast Field Reversal and Slow Field Reversal modes. The new protocol was validated within the framework of the application of the Smoluchowski approximation. Its performances complied with the ISO standard. The protocol could be applied to evaluate mean zeta potential of soft nanomaterials including polymer-based nanoparticles and liposomes. However, it appeared unsuitable to evaluate zeta potential of dense nanomaterials including rutile titanium dioxide nanoparticles. Compared with the previously validated protocol which only applied to the determination of zeta potential of polymer nanoparticles, this new validated protocol gives access to the determination of zeta potential to a wider range of nanomedicines under conditions complying with quality control assessments.