High efficiency upconversion nanophosphors for high-contrast bioimaging.

Area of Science:

• Materials Science
• Biotechnology
• Optical Imaging

Background:

• Upconversion nanoparticles (UCNPs) offer advantages over dyes for bio-imaging, including reduced autofluorescence, lower excitation thresholds, and improved photostability.
• Yttrium vanadate (YVO4) doped with erbium (Er+3) and ytterbium (Yb+3) exhibits strong upconversion luminescence at low excitation intensities, making it suitable for biological applications.

Purpose of the Study:

• To evaluate YVO4:Er+3, Yb+3 nanoparticles as internal probes for bio-imaging within insects.
• To demonstrate the feasibility of obtaining high-contrast 2D optical images of internal biological structures.

Main Methods:

• Injection of YVO4:Er+3, Yb+3 nanoparticles into fire ants (biological model).
• 2D optical imaging using 980 nm illumination.
• Detection of upconversion fluorescence during scanned laser excitation.

Main Results:

• Successful visualization of internal structures within fire ants using UCNPs.
• High-contrast images with a high signal-to-noise ratio were obtained.
• Demonstrated the effectiveness of UCNPs for in vivo bio-imaging in insects.

Conclusions:

• YVO4:Er+3, Yb+3 nanoparticles are effective internal probes for deep tissue bio-imaging in insects.
• The low excitation intensity requirement and high signal quality make these UCNPs promising for various bio-imaging applications.