Sequential assembly of DNA nanoparticles inside cells enables lysosome interference and cell behavior regulation

The artificial manipulation of exogenous molecules in living cells is a promising means to regulate cellular behaviors. However, the spatiotemporal control of self-assembly within the complex intracellular environment remains grand challenge. Herein, we report a controlled sequential assembly of DNA nanoparticles in living cells, responding to acidic environment in lysosome, which enables lysosome interference and subsequently regulates a series of cellular behaviors. Two types of ultra-long DNA chains (DNA-chain-1 and 2) synthesized via rolling circle amplification were compressed by magnesium ion to two DNA nanoparticles (DNP-1 and 2), respectively. In the acidic environment of lysosomes, both DNP-1 and DNP-2 dissociated to DNA chains, and the DNA chains were subsequently assembled through base-pairing to form a hydrogel. This sequential assembly process consumed hydrogen ions within the lysosome, decreased lysosomal acidity, and thus altered the hydrolase activity and lysosomal membrane permeability. The interference of sequential assembly on lysosomes promoted cell movement in human breast adenocarcinoma MCF-7 cells, with 81.19% and 36.24% enhancement in cell migration and invasion capacity, respectively; the level of cellular autophagy was increased by 170.00%. Our study provides a new strategy for the sequential assembly of exogenous DNA materials in living cells.