Electrostatic deposition of nanoparticles into live cell culture using an electrospray differential mobility analyzer (ES-DMA)

Global bionanotechnology efforts require precise correlation between well characterized nanoparticles and evaluation of their unique properties for medicinal applications and potential nanotoxicity. However, delivering aerosolized nanoparticles to cell culture remains the critical, unresolved link between aerosol based classification of highly uniform nanoparticles and nanotoxicology studies, critical to developing nanomaterials for nanomedicine applications. This article demonstrates a novel method to deposit aerosolized nanoparticles on live DU145 prostate cancer cells in culture, utilizing electrospray differential mobility analysis (ES-DMA) systems. ES-DMA is a well established technique to both generate highly uniform nanoparticles (σ/μ≤0.05) and characterize and separate aerosolized particles regardless of source with subnanometer precision. However, delivering these precisely sized materials to live cell culture remains the challenging and progress limiting step. We demonstrate delivery of aerosolized particles by electrostatically driving them into cell culture media. We explore parameters that affect cellular viability in the electrostatic deposition chamber and evaluate the physical mechanisms governing deposition. We find preserving a thin liquid layer covering the cells to be vitally important with a 1 mm average thickness sufficient to ensure cellular viability after 15 min of particle deposition. Higher humidity environments or lower aerosol flow rates increase the time of exposure without compromising the viability. The data indicate insufficient momentum for particles to ballistically penetrate through cellular membranes. This study is important because it enables aerosol based technologies to contribute broadly to fundamental problems in nanomedicine and nanotechnology.