Optomechanical Time-Gated Fluorescence Imaging Using Long-Lived Silicon Quantum Dot Nanoparticles.

Area of Science:

• Optomechanics
• Biophotonics
• Fluorescence Imaging

Background:

• Autofluorescence in biological samples limits imaging contrast.
• Traditional time-gating methods often require expensive pulsed lasers or image intensifiers.
• Live zebrafish are valuable models for studying biological processes.

Purpose of the Study:

• To demonstrate a novel, cost-effective optomechanical synchronization method for time-gated fluorescence imaging.
• To improve signal-to-background ratio (SBR) in fluorescence microscopy.
• To enable multiplexing of fluorescence signals in live biological models.

Main Methods:

• Utilized silicon quantum dot nanoparticles (SiQDNPs) with long photoluminescence lifetimes (~16 μs) as probes.
• Employed a rotating optical chopper synchronized with a continuous-wave laser for time-gating.
• Integrated excitation and detection windows using a single optical chopper to eliminate the need for ultrafast shutters.

Main Results:

• Achieved ultrahigh-contrast time-gated fluorescence imaging in live zebrafish.
• Demonstrated effective removal of background autofluorescence from the zebrafish yolk sac.
• Reported a 45-fold increase in signal-to-background ratio.
• Successfully separated fluorescence signals from SiQDNPs and intrinsic green fluorescent protein.

Conclusions:

• The developed optomechanical synchronization method offers a cost-effective approach to time-gated fluorescence imaging.
• This technique significantly enhances imaging contrast and enables multiplexing in live biological systems.
• The method holds promise for advanced bioimaging applications in zebrafish models.