1 research outputs found
Tunable Fluorescence of a Semiconducting Polythiophene Positioned on DNA Origami
A novel
approach for the integration of π-conjugated polymers
(CPs) into DNA-based nanostructures is presented. Using the controlled
Kumada catalyst-transfer polycondensation, well-defined thiophene-based
polymers with controllable molecular weight, specific end groups,
and water-soluble oligoethylene glycol-based side chains were synthesized.
The end groups were used for the easy but highly efficient click chemistry-based
attachment of end-functionalized oligodeoxynucleotides (ODNs) with
predesigned sequences. As demonstrated by surface plasmon resonance
spectroscopy, the prepared block copolymers (BCPs), P3Â(EO)<sub>3</sub>T-<i>b</i>-ODN, comprising different ODN lengths and specific
or repetitive sequences, undergo specific hybridization with complementary,
thiol-functionalized ODNs immobilized on a gold surface. Furthermore,
the site-specific attachment of the BCPs to DNA origami structures
is studied. We demonstrate that a nanoscale object, that is, a single
BCP with a single ODN handle, can be directed and bound to the DNA
origami with reasonable yield, site-specificity, and high spatial
density. On the basis of these results, we are able to demonstrate
for the first time that optical properties of CP molecules densely
immobilized on DNA origami can be locally fine-tuned by controlling
the attractive π–π-stacking interactions between
the CPs. In particular, we show that the fluorescence of the immobilized
CP molecules can be significantly enhanced by surfactant-induced breakup
of π–π-stacking interactions between the CP’s
backbones. Such molecular control over the emission intensity of the
CPs can be valuable for the construction of sophisticated switchable
nanophotonic devices and nanoscale biosensors