Polymer particles, such as polylactic-co-glycolic acid (PLGA), are often studied as potential drug delivery vehicles, but further understanding of their behavior in the biological environment is necessary to achieve a successful drug delivery system. One major hurdle for drug delivery vehicles is evading clearance by the immune system before reaching the intended targets. If the particles aggregate in blood, then the aggregated particles will be removed by the immune system. The surface chemistry of a particle is critical to its aggregation behavior, yet measuring aggregation in a complex solution such as blood is difficult. Nanoparticle Tracking Analysis (NTA) is a powerful tool for analyzing nanoparticles in solution. By using fluorescently labeled particles, particles can be analyzed in complex solutions such as blood plasma. Analysis in blood plasma allows for quantification of heterogenous aggregation of the particles (i.e. particles with proteins) that wouldnât be captured by other methods.
In this work PLGA particles were made via electrohydrodynamic co-jetting. They were subsequently modified to add either poly(ethylene glycol) monolayers, poly(ethylene glycol) methacrylate (PEGMA) brushes, or poly(carboxybetaine methacrylate) (PCBMA) brushes to the particle surface. The particles were incubated in blood plasma and analyzed with NTA. The aggregation behavior of the particles was observed and quantified and compared to the heterogeneous aggregation behavior observed with unmodified PLGA particles.