DNA Origami and G-Quadruplex Hybrid Complexes Induce Size Control of Single-Walled Carbon Nanotubes via Biological Activation.

DNA self-assembly has enabled the programmable fabrication of nanoarchitectures, and these nanoarchitectures combined with nanomaterials have provided several applications. Here, we develop an approach for cutting single-walled carbon nanotubes (SWNTs) of predetermined lengths, using DNA origami and G-quadruplex hybrid complexes. This approach is based on features of DNA: (1) wrapping SWNTs with DNA to improve the dispersibility of SWNTs in water; (2) using G-quadruplex DNA to confine hemin in close proximity to SWNTs and enhance the biological activation of hydrogen peroxide by hemin; and (3) forming DNA origami platforms to allow for the precise placement of G-quadruplexes, enabling size control.

Harnessing the hygroscopic and biofluorescent behaviors of genetically tractable microbial cells to design biohybrid wearables.

Cells' biomechanical responses to external stimuli have been intensively studied but rarely implemented into devices that interact with the human body. We demonstrate that the hygroscopic and biofluorescent behaviors of living cells can be engineered to design biohybrid wearables, which give multifunctional responsiveness to human sweat. By depositing genetically tractable microbes on a humidity-inert material to form a heterogeneous multilayered structure, we obtained biohybrid films that can reversibly change shape and biofluorescence intensity within a few seconds in response to environmental humidity gradients.

Weighing nanoparticles in solution at the attogram scale.

Physical characterization of nanoparticles is required for a wide range of applications. Nanomechanical resonators can quantify the mass of individual particles with detection limits down to a single atom in vacuum. However, applications are limited because performance is severely degraded in solution.

Ligand-induced electron spin-assembly on a DNA tile.

By binding of a ligand molecule carrying an electron spin to a guanine-guanine mismatch in a DNA duplex on a DNA tile, a three-dimensional assembly of electron spins was successfully constructed.

Tandem arrays of TEMPO and nitronyl nitroxide radicals with designed arrangements on DNA.

Herein we describe one-dimensional electron-spin arrays consisting of two different organic radicals with the designed arrangement based on the DNA sequence. Two mismatch-binding ligands carrying 2,2,6,6-tetramethylpiperidine N-oxide (TEMPO) and nitronyl nitroxide selectively bind to the predetermined sites on double stranded DNA. By using the two mismatch-binding ligands carrying the organic radicals as the glue for DNA, electron-spin assembly could be successfully synchronized with the hybridization.

Ligand inducible assembly of a DNA tetrahedron.

Here we show that a small synthetic ligand can be used as a key building component for DNA nanofabrication. Using naphthyridinecarbamate dimer (NCD) as a molecular glue for DNA hybridization, we demonstrate NCD-triggered formation of a DNA tetrahedron.

Programmed assembly of organic radicals on DNA.

Nitronyl nitroxide radical introduced to naphthyridine carbamate dimer is noncovalently bound to a CGG/CGG triad as an addressable position in DNA duplexes, leading to the programmed assembly of the radical molecules into an 11-mer duplex and a tandem repetitive array of double stranded DNA.

Fluorescence-based affinity labeling of nucleobase by hydrogen-bond forming metal complex.

A new class of nucleobase-binding fluorescent ligand, ND-DOTA in which 2-amino-5,7-dimethyl-1.8-naphthyridine (ND) is conjugated with 1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid (DOTA) by an amide linker, was synthesized. On the basis of the experimental results obtained from the DNA melting analysis and fluorescent measurement, ND-DOTA-Tb (III) complex was found to strongly recognize cytosine (C) base opposite an abasic site in DNA duplexes.