Single-Molecule Detection of a Fluorescent Nucleobase Analogue via Multiphoton Excitation.

ABSTRACT: The ability to routinely detect fluorescent nucleobase analogues at the single-molecule level would create a wealth of opportunities to study nucleic acids. We report the multiphoton-induced fluorescence and single-molecule detection of a dimethylamine-substituted extended-6-aza-uridine (DMA^thaU). We show that DMA^thaU can exist in a highly fluorescent form, emitting strongly in the visible region (470-560 nm). Using pulse-shaped broadband Ti:sapphire laser excitation, DMA^thaU undergoes two-photon (2P) absorption at low excitation powers, switching to three-photon (3P) absorption at high incident intensity. The assignment of a 3P process is supported by cubic response calculations. Under both 2P

SUBMITTER: Nobis D 

PROVIDER: S-EPMC7024020 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature