Upconversion Nanoprobes for the Ratiometric Luminescent Sensing of Nitric Oxide

Area of Science:

• Nanotechnology
• Biomedical Engineering
• Analytical Chemistry

Background:

• Nitric oxide (NO) is a crucial signaling molecule in biological systems.
• Accurate measurement of NO in complex biological matrices remains challenging.
• Upconversion nanoparticles (UCNPs) offer unique optical properties for sensing applications.

Purpose of the Study:

• To design and validate a luminescence ratiometric nanosensor for quantifying nitric oxide (NO).
• To utilize the optical properties of UCNPs for sensitive NO detection.
• To demonstrate the nanosensor's applicability in biological fluids, live cells, and tissues.

Main Methods:

• Fabrication of a nanoconjugate comprising UCNPs, mesoporous silica (mSiO2) shell, and β-cyclodextrin (βCD) layer.
• Encapsulation of NO-reactive rhodamine B-derived molecules (RdMs) within the mSiO2 mesopores.
• Utilizing the spectral overlap between UCNP emission and RdM absorption changes upon NO reaction for ratiometric detection.

Main Results:

• The nanosensor exhibits a ratiometric response (I656/I540) that quantitatively correlates with nitric oxide concentration.
• The reaction mechanism involves RdM spiro-ring opening upon interaction with NO, leading to a detectable spectral shift.
• Successful validation of the assay in buffer solutions, serum, and mouse liver tissue slices.

Conclusions:

• The developed UCNP-based nanosensor provides a sensitive and reliable platform for NO detection.
• This ratiometric sensing approach enables accurate NO quantification in diverse biological settings.
• The nanosensor holds potential for advancing NO-related research and diagnostics.