Non-bleaching fluorescence emission difference microscopy using single 808-nm laser excited red upconversion emission

Area of Science:

• Nanotechnology
• Optical Microscopy
• Biomaterials

Background:

• Optical super-resolution microscopy enables nanoscale imaging.
• Fluorescence emission difference (FED) microscopy offers facile super-resolution without high laser intensity.
• Existing FED biomarkers often suffer from photobleaching, limiting imaging duration.

Purpose of the Study:

• To demonstrate non-photobleaching super-resolution imaging using FED microscopy.
• To introduce Er3+ activated upconverting nanoparticles (UCNPs) as novel biomarkers for FED microscopy.
• To address the photobleaching limitations of current FED microscopy agents.

Main Methods:

• Utilized Er3+ activated upconverting nanoparticles (UCNPs) with red-color emission and non-photobleaching properties.
• Employed Nd3+ dopant ions as sensitizing ions for efficient near-infrared 808-nm CW laser excitation.
• Investigated monodispersed NaYF4:Nd3+/Yb3+/Er3+@NaYF4:Nd3+ UCNPs through simulations and experiments.

Main Results:

• Successfully demonstrated non-photobleaching super-resolution imaging with FED microscopy.
• Er3+ activated UCNPs exhibited red-color emission and resistance to photobleaching.
• Low-power 808-nm CW laser excitation reduced potential tissue damage.
• Multiphoton properties of UCNPs showed easy saturation, beneficial for resolution enhancement.

Conclusions:

• Er3+ activated UCNPs provide a viable solution for non-photobleaching super-resolution imaging in FED microscopy.
• The developed UCNPs offer potential for reduced light-induced tissue damage.
• This approach significantly enhances the capabilities and potential applications of FED microscopy.