Molecular-Fluorescence Enhancement via Blue-Shifted Plasmon-Induced Resonance Energy Transfer

Area of Science:

• Nanotechnology
• Spectroscopy
• Materials Science

Background:

• Plasmon-induced resonance energy transfer (PIRET) is a mechanism for energy transfer between nanoparticles and molecules.
• Förster resonance energy transfer (FRET) is a common method for studying molecular interactions, but it has limitations.

Purpose of the Study:

• To demonstrate and characterize molecular fluorescence enhancement using blue-shifted PIRET from single gold nanorods (AuNRs) to merocyanine (MC) dye molecules.
• To compare the advantages of AuNRs as donors in PIRET with conventional molecular donors in FRET.

Main Methods:

• Utilized single AuNRs as donors and merocyanine (MC) dye molecules as acceptors.
• Investigated the spectral overlap between AuNR scattering and MC absorption for blue-shifted PIRET.
• Analyzed fluorescence enhancement and scattering quenching in AuNR-MC systems.

Main Results:

• Observed significant molecular fluorescence enhancement via blue-shifted PIRET.
• AuNRs exhibited larger absorption cross-sections compared to conventional FRET donors.
• PIRET showed a slower decrease in efficiency with increasing donor-acceptor distance than FRET.
• Blue-shifted PIRET enabled excitation with lower energy light than MC absorption, overcoming Stokes shift limitations.

Conclusions:

• AuNRs are effective donors for enhancing molecular fluorescence through PIRET.
• Blue-shifted PIRET offers advantages over FRET, including efficient excitation and improved energy transfer efficiency at greater distances.
• This technique holds promise for advancing nanoparticle-molecule hybrids in biosensing and bioimaging by improving signal-to-noise ratio and reducing photodamage.