Abstract: Compositions containing populations of nanoparticles that show selective uptake by tissues and other cell types such as lung cells and/or bone marrow cells are described. The nanoparticles show this uptake by virtue of their size and in the absence of a targeting agent on the surface of the nanoparticles, i.e., passive targeting. The population of nanoparticles contain poly(lactic acid-co-glycolic acid), have a diameter between about 70 nm and about 220 nm, and at least 90% of the nanoparticles have a diameter between about 110 nm and about 129 nm. The nanoparticles are manufactured using a microfluidic system. The compositions can be used to treat lung- and/or blood-related genetic disorders in in vivo gene editing technologies.