The Effect of Ligand Reactivity and Carrier Mechanics on Thiol‐Mediated Cellular Uptake for miRNA Nano‐Drugs

Abstract

ABSTRACT Thiol‐mediated uptake (TMU) is a powerful strategy for promoting the cellular uptake of nano‐drugs; however, the mechanochemical principles that coupled ligand reactivity, carrier mechanics, and receptor clustering remain poorly understood. Herein, the effect of carrier rigidity and cyclic disulfide reactivity on the thiol‐mediated cellular uptake of miRNA nano‐drugs was revealed. Compared with lipoic acid (LA), the higher enhancing effect of asparagusic acid (AspA) is identified with the greater affinity, higher binding stability, and more double‐disulfide binding. The greater association of AspA‐TFRC was also visualized by super‐resolution microscopy imaging. Molecular dynamics simulation further verified the superior membrane disruption and deeper insertion induced by AspA. However, both LA and AspA display concentration‐dependent self‐activation and self‐inhibition effects on exchanging with thiols. Furthermore, we provided direct evidence that thiolation can significantly accelerate endocytosis of rigid mesoporous silica nano‐drugs, whereas thiolation will shift the entry cell pathway of soft lipid nano‐drugs from endocytosis to membrane fusion, and AspA is more efficient. This work establishes a mechanochemical framework that links ligand reactivity, carrier mechanics, and receptor engagement to predict the cellular uptake mechanism of a thiol‐mediated nano‐drug delivery system.