Evaluating cell cycle- and autophagy-associated cellular accumulation of lipid-based nanoparticles.

Little is known about how cell cycle and autophagy, two fundamental life processes, affect cellular accumulation of nanoparticles. What's even more tough is that several long-lasting methodological barriers have hindered the progress of related research. Here we firstly show the construction of a multi-functional platform for overcoming existing methodological obstacles through integrating multiple technical approaches including autophagy-related gene 7 knockout to specifically block autophagy, PIP-FUCCI transfection and mitotic shake-off to thoroughly separate cell cycle phases, and 3D reconstruction to stereoscopically evaluate cellular accumulation of nanoparticles. Further application of this platform reveals that after a 2-hour incubation of lipid-based nanoparticles, G2-phase and M-phase cells, two populations previously muddled up together as G2/M-phase cells, respectively exhibited the maximum and minimum nanoparticle accumulation. Meanwhile, our data preliminarily suggest enhanced nanoparticle accumulation by autophagy blockade. Besides cell cycle and autophagy, comprehensive statistical analyses reveal a close association between cellular accumulation of nanoparticles and nanoparticle type. This study not only provides a valuable technical strategy, but uncovers important characteristics of cellular accumulation of nanoparticles, offering new insights for optimization and application of nanomedicines.