Application Of Functional DNA Nanostructures In Bioimaging

The use of DNA as a material has become commonplace, especially with theemergence of DNA nanotechnology.A large number of well-defined DNAnanostructures of varying dimensions, shapes and geometries have been assembled byexploiting the highly specific and programmable nature of DNA base pairing. Amongthe many potential uses of DNA nanostructures, biological and biomedicalapplications are very attractive given the biological nature of DNA.DNA is typically impermeable to the plasma membrane due to its polyanionicnature. Interestingly, several different DNA nanostructures can be readily uptaken bycells in the absence of transfection agents.we developed DNA tetrahedra that showprogrammed configuration switching in response to external stimuli. By adapting aseries of DNA structures (i-motif,anti-ATP aptamer (AAA),T-rich mercury-specificoligonucleotide (MSO),and hairpin structures) to DNA tetrahedra, we constructedAND, OR, XOR, and INH logic gates, as well as a half-adder operation. In addition,we also demonstrated the use of DNA logic gates for intracellular detection of ATP inliving cells.It suggest new opportunities for constructing intelligent cargo delivery systemsfrom these biocompatible, non-viral DNA nanocarriers.However, the underlyingmechanism of entry of DNA nanostructures into cells remains unknown. Here, weinvestigated the endocytotic internalization and subsequent transport of tetrahedralDNA nanostructures (TDNs) by mammalian cells through single-particle tracking. Wefound that the TDNs were rapidly internalized by a caveolin-dependent pathway.After endocytosis, the TDNs were transported tolysosomes in a highly ordered,microtubule-dependent manner. Whereas the TDNs retained their structural integrity within cells over long time periods, their localization in lysosomes precludes their useas effective delivery agents. To modulate the cellular fate of the TDNs, wefunctionalized them with nuclear localization signals (NLSs) that directed their escapefrom lysosomes and entry into cellular nuclei. This study improves our understandingof DNA nanostructure entry into cells and transport pathways, and can be used as thebasis for designing DNA nanostructure-based drug delivery nanocarriers for targetedtherapy.DNA nanoprobes with high FRET efficiency are synthetised effectively usingDNA nanotechenology. We demonstrate a DNA nanotechnology-based approach toencode the non-linearity of fluorescence required for sub-diffraction imaging influorescent probes with an internal high-efficiency F rster resonance energy transferpair. We have achieved65-nm resolution imaging of microtubule filaments using astandard confocal microscope. we expect this low-cost, easy super-resolutionmicroscopy will find widespread applications in biological and biomedical studies.DNA nanoprobes can covalently coupled with antibodies very efficiently andeach other keep the activity. Antibodies have the ability to identify very specificpoints, plays an irreplaceable role in the targeted delivery,targeted therapy and otheraspects of fluorescence imaging. DNA covalently coupled with antibody will greatlyexpand the application of DNA nanomaterials in the biomedical field. The FRETeffect can be used not only to detect interaction of protein molecules but also influorescence imaging which can reduce the background fluorescence, improve theratio of signal to noise. FRET with high efficiency can achieve DNS super-resolutionmicroscopy imaging. Given to the specie diversity of antibodies,we can realize doubleFRET cell fluorescence imaging of two proteins.