The Construction Of Novel Self-Assembled Nucleic Acid Nanoprobes And Its Application In Biosensing And Imaging Analysis

DNA nanotechnology was first proposed in 1982 by professor Seeman of New York University. After 20 years of development, the self-assembly of DNA tile, DNA origami and nanofabrication have been used to prepare many kinds of DNA nanostructures. Nucleic acid probes constructed by DNA and RNA have the advantages of easy modification, feasitile design and stability, which play an important role in biosensing, achieving target molecule recognition, signal transduction and amplification. Design of one multifunctional DNA nanostructure can lead to many novel nucleic acid self-assembly route, which hold great prospects in biosensing, targeted drug delivery, cancer treatment and other applications. We have carried out the following work on nucleic acid self-assembly techniques:1. Self-assembled multifunctional DNA nanospheres for biosensing and drugdelivery into specific target cellsSelf-assembling of three dimensional nucleic acid nanostructures is of great significance in nanotechnology, biosensing and biomedicine. Herein we present a novel class of multifunctional and programmable DNA nanostructures, termed as nanospheres (NSs), with monodispersity, dense compaction and uniform size (-200 nm) using only four DNAs based on not only Watson-Crick base pair hybridization between single-stranded DNA but also liquid crystallization and dense packaging from periodic DNA duplexes. Due to the diversity of the internal structures, the present NSs can be easily evolved into other kinds of DNA assemblies, such as DNA spherical structures with larger size and rough surface via rolling circle replication (RCR). Importantly, the functional arms reserved in building units can be readily designed for biosensing and targeted cancer therapy with high payload capacity and excellent biocompatibility. Therefore, the proposed NSs could lead to novel routes for nucleic acids self-assembly, promising versatile applications in biosensing and biomedicine.2. Chemiluminescence resonance energy transfer imaging detection of microRNA based on four-juction DNA nanostructures and DNA nanospheresThis chapter proposes a new DNA self-assembly method for sensitive and selective detection of microRNA based on a four-juction DNA structure and self-assemble of DNA nanospheres. Starting from the construction of DNA structure, we have designed multifunctional DNA hairpin structures to avoid the restriction of microRNA bases and reaction conditions based on the complementary hybridization between DNA structures and strand displacement reaction to self-assemble four-fuction DNA nanostructures and DNA nanospheres. During this process, microRNA can be recycled, achieving sensitive and selective detection of microRNA.