Multiplex microRNA imaging in living cells usingDNA-capped-Au assembled hydrogels

摘要

Non-invasively imaging multiplex microRNAs (miRNAs) in living cells is pivotal to understanding theirphysiological functions and pathological development due to the key regulatory roles of miRNAs in geneexpression. However, developing smart delivery systems with large gene loading capacity, biocompatibilityand responsiveness remains a significant challenge. Herein, we successfully incorporated DNA-capped Aunanoparticles (NPs) and their complementary fluorescent DNA sequences into a porous 3D hydrogelnetwork (AuDH), in which hairpin-locked DNAzyme strands and active metal ions were loaded(AuDH/Mn+/H) for simultaneously imaging multiplex miRNAs in living cells. After transfection into cells, thespecific miRNAs trigger the strand-displacement reaction and sequentially activate the DNAzyme-assistedtarget recycling, leading to a strong increase in the corresponding fluorescence intensity for imaging. Thisenables simultaneous assessment of the abundance of multiplex cancer-related miRNAs, even if at a verylow expression level, in different cells through the different fluorescence intensities due to the dual signalamplification, and the change in abundance of miRNAs induced by siRNA or miRNA mimics in living cellscan also be efficiently monitored. The versatile and responsive DNA hydrogel system holds great potentialfor miRNA biomedical applications.