sub-nanometer-resolution-imaging-with-amplitude-modulation-atomic

Sub-nanometer Resolution Imaging with Amplitude-modulation Atomic Force Microscopy in Liquid

Atomic force microscopy (AFM) has become a well-established technique for nanoscale imaging of samples in air and in liquid. Recent studies have shown ...

Durham University

A DNA-origami actuator capable of autonomous internal motion in accord to an external chemical signal was designed, built, operated and imaged. The functional DNA nanostructure consists of a disk connected to an external ring in two, diametrically opposite points. A single stranded DNA, named probe, was connected to two edges of the disk perpendicularly to the axis of constrain. In the presence of a hybridizing target molecule, the probe coiled into a double helix that stretched the inner disk forcing the edges to move toward each other. The addition of a third single stranded molecule that displaced the target from the probe restored the initial state of the origami. Operation, dimension and shape were carefully characterized by combining microscopy and fluorescence techniques.

A revertible, autonomous, self-assembled DNA-origami nanoactuator.

A prototype for a DNA origami nanorobot is designed, produced, and tested. The cylindrical nanorobot (diameter of 14 nm and length of 48 nm) with a switchable flap, is able to respond to an external stimulus and reacts by a physical switch from a disarmed to an armed configuration able to deliver a cellular compatible message. In the tested design the robot weapon is a nucleic acid fully contained in the inner of the tube and linked to a single point of the internal face of the flap. Upon actuation the nanorobot moves the flap extracting the nucleic acid that assembles into a hemin/G-quadruplex horseradish peroxidase mimicking DNAzyme catalyzing a colorimetric reaction or chemiluminescence generation. The actuation switch is triggered by an external nucleic acid (target) that interacts with a complementary nucleic acid that is beard externally by the nanorobot (probe). Hybridization of probe and target produces a localized structural change that results in flap opening. The flap movement is studied on a two-dimensional prototype origami using Förster resonance energy transfer and is shown to be triggered by a variety of targets, including natural RNAs. The nanorobot has potential for in vivo biosensing and intelligent delivery of biological activators.

A DNA origami nanorobot controlled by nucleic acid hybridization.

A strategy for an innovative, continuous and reversible LSPR tuning using DNA origami actuation to modulate the nanometric separation of two gold nanoparticles has been developed. The actuation mechanism is based on DNA hybridization, in particular three different DNA sequences were shown to induce resonance shift of up to 6 nm.

Article	Year
A revertible, autonomous, self-assembled DNA-origami nanoactuator. Nano letters\| PubMed ID: 22047682	2011
A DNA origami nanorobot controlled by nucleic acid hybridization. Small (Weinheim an der Bergstrasse, Germany)\| PubMed ID: 24648163	2014
Plasmon resonance tuning using DNA origami actuation. Chemical communications (Cambridge, England)\| PubMed ID: 25692733	2015

Luca Piantanida

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