Figure 1. Physicochemical properties of carrier systems.

Size, shape, and charge of nanoparticle systems are the key determinants which impact cellular uptake, cell toxicity, immunogenicity, and the efficacy of the delivered cargo. a.) Carrier size plays a key role in their diffusion profile, adhesion properties, and velocity distribution, all which contribute to the uptake efficiency of particles. b.) Carrier shape effects transport, degradation, internalization, clearance, and even targeting. Most nanoparticles that are designed for intravenous delivery exhibit spherical geometry 10-100 nm in diameter. Particles > 200 nm accumulate in the liver and spleen, and are subsequently cleared by reticuloendothelial system. c.) The surface charge of delivery systems also influences circulation stability and uptake mechanisms by having effects on the molecular interactions between carriers and their target cells, as well as subsequent downstream intracellular events.