Single-particle electrophoresis to study the adsorption of polyplexes onto anionic particles: A model system for investigating polyplex-cell interactions

Abstract

Gene therapy is being used in many applications, including pest control and the treatment of diseases. However, protection during transport and delivery of the genetic material to the desired location remain important challenges. Cationic polymers have certain key advantages as delivery vectors, but the toxicity and transfection efficiency of new polymers are unpredictable and the polyplex-cell interactions remain largely underinvestigated. In this work, we aimed to study the electrostatic interactions of polyplexes with anionic particles, which serve as a simple model for a cell. To this end, we used single-particle electrophoresis to measure the electrophoretic mobility of the particles upon interacting with the polyplexes. We found that the dominant factor influencing the adsorption kinetics is the polymer concentration, while the N/P ratio has a smaller effect, at least in the investigated range. This research establishes single-particle electrophoresis as a new tool to study one of the processes involved in cytotoxicity and transfection and could have strong implications regarding the unraveling of the key parameters involved.