Functionalized DNA nanostructures for bioimaging

The excellent molecular recognition, programmable and biocompatible properties make deoxyribonucleic acid (DNA) a kind of material widely used in biomedical field. DNA nanostructures enable nanometer-precise placement of nanomaterials and dyes are called functional DNA nanostructures (FDNAs). Functionalization improves the biostability, enhances cell internalization efficiency of DNA nanostructures by surface modification and facilitates them to play a significant role in the field of targeted bioimaging. The nanomaterials have shown promising physicochemical characteristics, such as simple functionality and tunable optical bands but often lack selectivity in bioimaging. The FDNAs paves the way for intriguing imaging platforms. The ease of attachment nanomaterials and dyes to DNA nanostructures provides higher specificity, biocompatibility and biostability, and as a result, small ions, molecules and proteins can be visualized. The FDNAs can be expected to be widely applied not only in advanced imaging as well as in organelle specific and ultra-sensitive molecular imaging. This review provides research progress in the field of bioimaging based on FDNAs. In this review, FDNAs based bioimaging probes are reviewed and summarized from several aspects, DNA nanostructures (DNA origami, DNA nanoflower and DNA tetrahedral), fabrication of FDNAs for bioimaging, properties of FDNAs in bioimaging, FDNAs for bioimaging and role of FDNAs in different imaging techniques. Finally, we have illustrated the major challenges and opportunities to advance the bioimaging field into clinical applications.