Programmable pH-responsive DNA Nanosensors for Imaging Exocytosis and Retrieval of Synaptic Vesicles.

Exocytosis and retrieval of synaptic vesicles (SVs) are vital steps during neurotransmitter propagation between neurons. Visualization of this dynamics of SVs is significant for elucidating the mechanisms underlying synaptic transmission but remains challeng-ing without an efficient, reliable, and biocompatible labeling method. In this work, we developed pH-responsive ratiometric DNA tetrahedral nanoprobes (pHadtnps) that could specifically label recycling SVs with high stability and effective background suppression. On the basis of the luminal pH alternation during the recycling of SVs, pHadtnps were able to illustrate their exocytosis and retrieval in real time. Moreover, with the high programmability of DNA nanotechnology, these nanoprobes could be flexibly equipped with different functional moieties, holding great promise for developing various versatile tools for studying communication in neuronal networks.