SCALE UP OF DNA-LINEAR POLYETHYLENIMINE NANOPARTICLES USING CONFINED IMPINGING JET MIXING
Vandermark, John Michael
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DNA-PEI nanoparticles are a popular and promising platform for non-viral DNA transfection platform. This platform is known for high transfection ability with easily prepared small batch formulations. This protocol becomes tedious and concerning when large volumes of particles are needed for animal studies. Using a confined impinging jet (CIJ) system to perform flash nano-complexation (FNC) on DNA and PEI solutions is a promising model for generating large volumes of particles with high reproducibility. Using the established engineering parameters of DNA concentration, polymer pH, and amine to phosphate (NP) ratio, similar trends of size and shape control, free polymer content, zeta potential, and transfection activity were observed for both batch and FNC mixing. On average, FNC mixing generated particles with smaller average sizes as well as a more narrow distribution of sizes. The FNC platform introduces a new variable, flow rate, which has the most pronounced effect on particle performance. At low flow rates, the FNC method produced particles with larger sizes than the batch mixed particles, suggesting that the flow rate, and the Reynolds number associated with the flow rate play a large role in the dynamics of mixing. Using a modelling package to run simulations, the turbulence in the chamber reaches a steady state at flow rates above 20 mL/ min, but a steady state is never reached at flow rates below 10 mL/min and dynamic mixing never occurs, explaining the large effect flow rate can have on particle assembly. This platform can easily accommodate lyophilized formulations, making the production of large batches of DNA-PEI nanoparticles more feasible.