External electric field modulation of polyelectrolyte complex nanoparticles for vaccine delivery

Polyelectrolyte complex nanoparticles (PECNs) are widely used as carrier systems, particularly for delivering nucleic acids and proteins. Their unique characteristics have led to extensive research into their potential as vaccine delivery platforms. Since PECNs form through electrostatic interactions, various solution and physical parameters can influence their structure during and after fabrication. We discovered that applying an electric voltage affects the physicochemical properties of PECNs comprised of chitosan complexed to a polyelectrolyte vaccine adjuvant. Subsequently, we explored the effect of voltage application on their physical properties and performance as vaccine nanocarriers. The nanoparticles were prepared using microfluidic mixing, with the physicochemical properties of these formulations assessed both before and after exposure to electric voltage. Results showed that exposure to electric voltage can alter the physicochemical properties of PECNs, subsequently impacting their in vitro efficacy. This also emphasizes the importance of carefully considering the sequential order of particle size and zeta potential determinations, as these parameters are derived from DLS and electrophoretic mobility measurements, respectively, and the latter can influence the physicochemical properties of PECNs.