Photoswitchable Oligonucleotide-Modified Gold Nanoparticles: Controlling Hybridization Stringency with Photon Dose

Abstract

We describe a new class of stimulus-responsive DNA-functionalized gold nanoparticles that incorporate azobenzene-modified oligonucleotides. Beyond the classic directed assembly and sensing behaviors associated with oligonucleotide-modified nanoparticles, these particles also exhibit reversible photoswitching of their assembly behavior. Exposure to UV light induces a trans-cis isomerization of the azobenzene which destabilizes the DNA duplex, resulting in dissociation of the nanoparticle assemblies. The isomerization is reversible upon exposure to blue light, resulting in rehybridization and reassembly of the DNA-linked nanoparticle clusters. We show that perfectly complementary and partially mismatched strands exhibit clearly distinguishable photoinduced melting properties, and we demonstrate that photon dose can thus be used in place of temperature or ionic strength to control hybridization stringency with the ability to discriminate single-base mismatches.

Survey of Plasmonic Nanoparticles: From Synthesis to Application

“…Not only chemical reactions can be used to assemble nanoparticles but it is also possible to utilize external stimuli such as light, temperature, and magnetic fields to trigger the formation of superstructures. Yan et al introduced photoswitchable DNA that can be employed to assemble (or disassemble) gold nanoparticles depending on the wavelength of the irradiated light. Azobenzene moieties within the DNA molecules were used as photosensitive units.…”

Multicomponent nanoarchitectures for the design of optical sensing and diagnostic tools

“…Azobenzene-modied oligonucleotide-functionalized Au particles showed a reversible photo-switchable assembly. 152 Irradiation of UV light caused trans-cis isomerization of azobenzene, destabilizing the DNA duplex, resulting in the dissociation of the particle assemblies, which can be reassembled by illuminating them with blue light. Stable gold-silver core-shell structures were synthesized from the Au-DNA particles to generate DNA-embedded Au-Ag coreshell particles by the silver staining method, where the silver shell thickness is controllable based on the amount of silver staining solution used in the synthesis.…”

Light‐Responsive Colloidal Crystals Engineered with DNA

“…Light‐responsive PAEs were synthesized by using azobenzene‐modified DNA (azoDNA) as bonding elements such that the configurational change of azobenzene molecules (between trans‐ and cis‐ states) effects DNA hybridization or dehybridization, causing the bonding between, or dissociation of, PAEs, respectively. The azoDNA linkers explored herein were designed to exhibit large wavelength‐dependent melting temperature ( T m ) windows, substantially greater than designs previously explored for effecting simple aggregation/dissociation of amorphous DNA–nanoparticle assemblies . Unlike previous systems in which particle‐tethered azoDNA included tracts of ten‐base complementary strands to effect aggregation of nanoparticles, the designs reported herein involve strands with short “sticky ends,” typically between six and eight nucleotide bases and with 7–10 azobenzene moieties incorporated within the duplex that results from the hybridization of the sticky ends.…”

“…The azoDNA linkers explored herein were designed to exhibit large wavelength‐dependent melting temperature ( T m ) windows, substantially greater than designs previously explored for effecting simple aggregation/dissociation of amorphous DNA–nanoparticle assemblies . Unlike previous systems in which particle‐tethered azoDNA included tracts of ten‐base complementary strands to effect aggregation of nanoparticles, the designs reported herein involve strands with short “sticky ends,” typically between six and eight nucleotide bases and with 7–10 azobenzene moieties incorporated within the duplex that results from the hybridization of the sticky ends. This design enables the reorganization of PAEs even after they have bonded to one another to form a crystalline lattice and provides a wavelength‐dependent T m window suitable for cleanly controlling crystallization or subsequent disassembly.…”