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DNA Base Pair Resolution Measurements Using Resonance Energy Transfer Efficiency in Lanthanide Doped Nanoparticles

Delplanque, A., Wawrzynczyk, D., Jaworski, P., Katarzyna, M., Pawlik, K., Buckle, M., Nyk, M., Nogues, C., Samoc, M. (2015). PloS one, 10(3), e0117277.

Schema showing the enhancement of fluorescence induced by the proximity of a gold nanoparticle to a fluorescent probe. Double stranded DNA was used to maintain a fixed distance between a fluorophore and a gold nanoparticle. Maximum enhancement of luminescence intensity at 670nm wavelength after excitation at 394nm was observed at a distance of 26 base pairs (bp) of DNA (11nm).

Lanthanide-doped nanoparticles are useful for biodetection and bioimaging
techniques due to their unique chemical and optical properties. We present a method to transfer ultrasmall (ca. 8 nm) NaYF4 nanoparticles dispersed in organic solvent to an aqueous solution via oxidation of the oleic acid ligand.
Nanoparticles were functionalized with single strand DNA oligomers (ssDNA) by inducing covalent bonds between surface carboxylic groups and 5' amine modified-ssDNA. Hybridization with 5' fluorophore (Cy5) modified complementary ssDNA strand demonstrated specificity of binding and the fine control over the distance between Eu3+ ions doped nanoparticles and the fluorophore. We confirmed nonradiative resonance energy transfer and the dependence of its efficiency on the distance between donors (Eu3+) and acceptors (Cy5) at a nanometre scale.