Conformational Details of Quantum Dot-DNA Resolved by Foerster Resonance Energy Transfer Lifetime Nanoruler
Abstract
DNA-nanoparticle conjugates are important tools in nano-biotechnology. Knowing the orientation, function, and length of DNA on nanoparticle surfaces at low nanomolar concentrations under physiological conditions is therefore of great interest. Here, we investigate the conformation of a 31 nucleotides (nt) long DNA attached to a semiconductor quantum dot (QD) via Foerster resonance energy transfer (FRET) from Tb-DNA probes hybridized to different positions on the QD-DNA. Precise Tb-to-QD distance determination from 7 to 14 nm along 26 nt of the peptide-appended QD-DNA was realized by time-resolved FRET spectroscopy. The FRET nanoruler measured linear single-stranded (ssDNA) and double-stranded (dsDNA) extensions of similar to 0.15 and similar to 0.31 nm per base, reflecting the different conformations. Comparison with biomolecular modeling confirmed the denser conformation of ssDNA and a possibly more flexible orientation on the QD surface, whereas the dsDNA was fully extended with radial orientation. The temporally distinct photoluminescence decays of the different DNA-FRET configurations were used for prototypical DNA hybridization assays that demonstrated the large potential for extended temporal multiplexing. The extensive experimental and theoretical analysis of 11 different distances/configurations of the same QD-DNA conjugate provided important information on DNA conformation on nanoparticle surfaces and will be an important benchmark for the development and optimization of DNA-nanobiosensors.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 03, 2018
- Accession Number
- AD1097662
Entities
People
- Carlos Mingoes
- Igor L. Medintz
- Jeffrey R. Deschamps
- Jiajia Guo
- Kimihiro Susumu
- Niko Hildebrandt
- Xue Qiu
Organizations
- United States Naval Research Laboratory