Sequential Assembly of Lipid Molecules Broadens Designability of Lipid-Based Nanoparticles

We present an unprecedent concept of "sequential assembly of lipid-based nanoparticles (LNPs)" by designing order of liquid-liquid interfaces based on microfluidic flow control. Unlike existing methods, our method enables to broaden the controllability of the LNP size without any changes of initial abundance ratio of lipids. We utilized a microfluidic chip having multi-inlets, and the configuration allows to change the order of the self-assembly relating to the size controllability. We demonstrated visualization of cellular uptake of LNPs with different size. From the results, we confirmed that the size was a critical factor for controlled transportation of LNPs into spheroids. The presented sequential assembly opens new paradigms of detailed analyses of live-cells.