A DNA origami plasmonic sensor with environment-independent read-out

Abstract

DNA origami is a promising technology for its reproducibility, flexibility, scalability and biocompatibility. Among the several potential applications, DNA origami has been proposed as a tool for drug delivery and as a contrast agent, since a conformational change upon specific target interaction may be used to release a drug or produce a physical signal, respectively. However, its conformation should be robust with respect to the properties of the medium in which either the recognition or the read-out take place, such as pressure, viscosity and any other unspecific interaction other than the desired target recognition. Here we report on the read-out robustness of a tetragonal DNA-origami/gold-nanoparticle hybrid structure able to change its configuration, which is transduced in a change of its plasmonic properties, upon interaction with a specific DNA target. We investigated its response when analyzed in three different media: aqueous solution, solid support and viscous gel. We show that, once a conformational variation is produced, it remains unaffected by the subsequent physical interactions with the environment.

Mechanically Tunable Nanogap Antennas: Single‐Structure Effects and Multi‐Structure Applications

“…c) Adapted with permission. [ 73b ] Copyright 2015, The Royal Society of Chemistry. d) Adapted with permission.…”

“…a plasmonic sensor utilizes the collapse of tetragonal DNA‐origami structures with attached nanoparticles to detect the presence of a target substance. [ 73a ] The 3ss DNA structure consisting of one double strand and three single strand segments deforms when a target substance is present. The deformation pushes the particles closer together, which is measurable by scattering or transmission optical spectroscopy or electron microscopy techniques.…”

“…have taken the flexibility of DNA origami to the next level by using a hybrid structure consisting of DNA folded into a trapdoor‐like structure and an initially unfolded DNA strand as an actor. [ 73b ] This strand connects the rim and the hatch and acts like a muscle opening the hatch when folded. Two nanoparticles are attached to the disk‐shaped DNA.…”

“…present tripod DNA origami structures. [ 73c ] To each pod, a gold nanorod is attached. An illustration of the structure is depicted in Figure 17d.…”

“…Besides the direct mechanical variation of nanogaps by means of stretching and bending of the substrate, many other techniques have been employed to control interparticle gaps using other external stimuli such as DNA hybridization, [ 9c,73 ] protein interactions, [ 74 ] light, [ 75 ] pH‐value, [ 76 ] chemical concentration, [ 77,78 ] temperature, [ 79 ] electrical charges, [ 80 ] or alternating currents, [ 81 ] and many more. [ 82 ] These stimuli can all lead to an indirect mechanical variation of the nanogap, in some cases also allowing for the reversible tuning of single nanogap antennas, and therefore to systems comparable to those described in Section 2.4.1.…”