Light-Induced Reversible DNA Ligation of Gold Nanoparticle Superlattices.

Angela F De Fazio,Iris Nandhakumar,Jason S Kahn,Antonios G Kanaras,Otto L Muskens,Matthew Richard Burton,Tom Brown,Afaf H El-Sagheer,Oleg Gang

doi:10.1021/acsnano.9b01294

Abstract

DNA-mediated self-assembly of nanoparticles has been of great interest because it enables access to nanoparticle superstructures that cannot be synthesized otherwise. However, the programmability of higher order nanoparticle structures can be easily lost under DNA denaturing conditions. Here, we demonstrate that light can be employed as an external stimulus to master the stability of nanoparticle superlattices (SLs) via the promotion of a reversible photoligation of DNA in SLs. The oligonucleotides attached to the nanoparticles are encoded to ligate using 365 nm light, effectively locking the SLs and rendering them stable under DNA denaturing conditions. The reversible process of unlocking these structures is possible by irradiation with light at 315 nm, recovering the structures to their natural state. Our work inspires an alternative research direction toward postassembly manipulation of nanoparticle superstructures using external stimuli as a tool to enrich the library of additional material forms and their application in different media and environments.

Highlights

B ottom-up approaches for the 3D organization of nanoparticles into larger structures are of utmost importance for the fabrication of materials with improved properties.[1]
Twoand three-dimensional superlattices were obtained via molecular interactions,[9] for instance between alkylthiolfunctionalized gold nanoparticles, as reported by Brust et al.[10] and Landman and co-workers.[11]
Scheme 1 shows the principle of our methodology, which is the ligation of the DNA in the formed nanoparticle SLs and the distinct role of this covalent cross-linking as a tool in combination with the thermal induction of nanoparticle crystal formation

Summary

Introduction

B ottom-up approaches for the 3D organization of nanoparticles into larger structures are of utmost importance for the fabrication of materials with improved properties.[1]. One batch of oligonucleotide-coated nanoparticles contains a 3-cyanovinylcarbazole modification, which can react upon irradiation at λ = 365 nm with an adjacent thymine in the complementary strand, to form an interstrand chemical bond. This photochemical process can be reversed upon irradiation with light at λ = 312 nm. Further exploitation of oligonucleotide-coated nanoparticles allowed the formation of programmed nanoparticle assemblies, starting from nanoparticle dimers and trimers to larger structures It was not until 2008 that SLs of oligonucleotide-coated gold nanoparticles were reported independently by the groups of Mirkin[25] and Gang.[26] In those works, both groups described the experimental conditions and oligonucleotide design rules to form bodycentered cubic and face-centered cubic organized gold nanoparticle assemblies. Another example was a convertible lattice obtained by means of reconfigurable DNA strands, which were able to switch between two states that yield two different lattice structures.[34]

Methods

Results

Conclusion