Integrating DNA nanostructures with DNAzymes for biosensing, bioimaging and cancer therapy

As a natural biomolecule, DNA shows excellent bio-friendliness, programmability and modifiability, and is an attractive building block for constructing nanostructures. In parallel, functional DNAs, such as DNAzyme with catalytic activity and aptamer with specific recognition function, which are easy to be prepared in vitro and show thrilling biological characteristics, play an emerging role in biology. The combination of DNA nanostructures and functional DNAs catalyzes the emergence of a series of functional nanosystems. In recent years, nano-products based on DNA nanostructures and DNAzyme have shown much more advantages and potential than traditional strategies in multiple fields, especially biosensing, bioimaging and disease treatment. And DNAzyme-integrated DNA nanostructures have become the focus of research and application, not least because of high sensitivity, low limit of detection, and low toxicity. In this review, we describe the selection of appealing DNAzyme by SELEX and preparation of DNAzyme-integrated DNA nanostructures, with emphasis on their application in biosensing and bioimaging of metal ions, nucleic acids, protein, enzyme activity, exosomes, cancer cells and bacterium, as well as targeted cancer therapy. Additionally, we discuss the challenges that these emerging nanostructures may encounter in practical application, and also conclude with a brief outlook on their bright prospect in more fields and multidisciplinary cooperation.