Abstract

Recently, DNA-based nano biomaterials have been greatly developed and widely applied owing to their sequence programmability, accurate self-recognition and instinct biocompatibility. However, DNA self-assembled nanostructures, like DNA rotors, DNA polyhedras and DNA walkers, are mostly formed through hybridization of ssDNA, which might bring perturbation to some active molecules or enzymes because of the high temperature needed. Herein, we propose a substrate-free method to construct a covalently bonded two-dimensional DNA nanostructure at room temperature. AFM and TEM images demonstrate that DNA vesicles are successfully constructed with monodisperse properties and stability. Based on above, we modified the vesicle with biotin and i-motif respectively. Fluorescence microscopy indicates that the vesicle could be readily functionalized with streptavidin through biotin-avidin interaction when modified with biotin, and DLS results confirm that the vesicle could respond to pH changes when modified with i-motif. We believe these vesicles would have wide applications in many areas, especially drug delivery. Title: Substrate-free Covalent Self-assembly of DNA Three-way Junctions into Multiple Nanostructures at room temperature.