Size-controlled biodegradable nanoparticles: preparation and size-dependent cellular uptake and tumor cell growth inhibition.

Biodegradable nanoparticles with diameters below 1000nm are of great interest in the contexts of targeted delivery and imaging. In this study, we prepared PLGA nanoparticles with well-defined sizes of ∼70nm (NP70), ∼100nm (NP100), ∼200nm (NP200), ∼400nm (NP400), ∼600nm (NP600) and ∼1000nm (NP1000) using facile fabrication methods based on a nanoprecipitation and solvent evaporation techniques. The nanoparticles showed a narrow size distribution with high yield. Then the size-controlled biodegradable nanoparticles were used to investigate how particle size at nanoscale affects interactions with tumor cells and macrophages. Interestingly, an opposite size-dependent interaction was observed in the two cells. As particle size gets smaller, cellular uptake increased in tumor cells and decreased in macrophages. We also found that paclitaxel (PTX)-loaded nanoparticles showed a size-dependent inhibition of tumor cell growth and the size-dependency was influenced by cellular uptake and PTX release. The size-controlled biodegradable nanoparticles described in this study would provide a useful means to further elucidate roles of particle size on various biomedical applications.