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Updated: Jun 19, 2026

Evaluation of Polymeric Gene Delivery Nanoparticles by Nanoparticle Tracking Analysis and High-throughput Flow Cytometry
Published on: March 1, 2013
Coaxial electrohydrodynamic spraying of plasmid DNA/polyethylenimine (PEI) polyplexes for enhanced nonviral gene
Yun Wu1, Zhengzheng Fei, L James Lee
1William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 140 W 19th Ave., Columbus, Ohio 43210, USA.
Abstract:
DNA/polyethylenimine (PEI) polyplexes are an important class of nonviral vectors. Although the conventional preparation method, bulk mixing, is straightforward, the formation of the DNA/PEI polyplexes is not well controlled. This work explores coaxial electrohydrodynamic spraying (EHDS) as a novel, alternative method to produce DNA/PEI polyplexes in a more controlled manner. Both pGFP/PEI and pSEAP/PEI polyplexes were produced by EHDS with a coaxial needle setup. The size of the polyplexes was determined using dynamic light scattering, and their ability to transfect NIH 3T3 cells was observed by using an inverted fluorescence microscope (pGFP) or quantified by measuring the activity level of alkaline phosphatase (pSEAP). At nitrogen to phosphate ratio (N/P) of 6.7, the polyplexes produced by coaxial EHDS had delivery efficiencies up to 2.6 times higher than those produced by bulk mixing. The N/P ratio and the structure of the EHDS used to make the polyplexes were crucial factors in determining the delivery efficiency.

