Quench-Shield Ratiometric Upconversion Luminescence Nanoplatform for Biosensing.

Area of Science:

• Nanotechnology
• Biochemistry
• Materials Science

Background:

• Upconversion nanoparticles (UCNPs) offer unique optical properties but are hindered by surface quenching.
• This quenching effect limits their application in biosensing and bioimaging due to fluorophore interactions.

Purpose of the Study:

• To develop a universal and efficient luminescence resonance energy transfer (LRET) ratiometric upconversion luminescence nanoplatform.
• To overcome the challenge of surface quenching in UCNPs for enhanced biosensing.

Main Methods:

• Engineered a silica transition layer (approx. 4 nm) to separate UCNPs and fluorophores, mitigating surface quenching.
• Constructed LRET nanoprobes using a pH-sensitive fluorescein derivative and a Hg(2+)-sensitive rhodamine B.

Main Results:

• Demonstrated effective separation of UCNPs and fluorophores via the silica layer, reducing quenching.
• Achieved satisfactory target-triggered ratiometric upconversion luminescence responses in solution and live cells.

Conclusions:

• The silica-separated UCNP platform provides a universal and efficient LRET nanoplatform for biosensing.
• This strategy shows promise for designing nanoprobes for diverse biorelated targets, applicable in bioimaging and biosensing.