Millisecond-Range Time-Resolved Bioimaging Enabled through Ultralong Aqueous Phosphorescence Probes.

Area of Science:

• Biomedical Imaging
• Materials Science
• Nanotechnology

Background:

• Room-temperature phosphorescence (RTP) probes offer potential for time-resolved imaging.
• Current bioimaging techniques are limited by short emission lifetimes, typically in the microsecond range.
• There is a need for imaging probes with longer emission lifetimes to improve signal detection and reduce background noise.

Purpose of the Study:

• To develop and demonstrate the first millisecond-range time-resolved bioimaging capability.
• To utilize novel ultralong aqueous phosphorescence probes for enhanced bioimaging applications.
• To achieve specific targeting and high signal-to-background ratios in complex biological systems.

Main Methods:

• Synthesis of cyclo-(Arg-Gly-AspD-Tyr-Cys)-conjugated zinc-doped silica nanospheres as ultralong phosphorescence probes.
• Characterization of probe emission lifetime, measuring approximately 5 seconds duration and a 743.7 ms lifetime.
• Application of immune-phosphorescence imaging for specific targeting of live cells and deep tumor tissues in mice.

Main Results:

• Achieved millisecond-range time-resolved bioimaging with a RTP emission lifetime of 743.7 ms.
• Demonstrated specific targeting of live cells and deep tumor tissue in mice.
• Obtained high signal-to-background ratios (SBR) of approximately 69 for in vitro and 627 for in vivo imaging.
• Showcased up to a 105-fold SBR enhancement compared to traditional fluorescence imaging for in vivo bioimaging.

Conclusions:

• Ultralong aqueous phosphorescence probes enable unprecedented millisecond-range time-resolved bioimaging.
• This technology significantly enhances imaging sensitivity and specificity in biological samples and deep tissues.
• The developed probes represent a major advancement for in vivo bioimaging, offering superior performance over conventional fluorescence methods.