Molecular Antenna-Sensitized Upconversion Nanoparticle for Temperature Monitored Precision Photothermal Therapy

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Materials Science

Background:

• Accurate, real-time temperature detection is crucial for clinical photothermal therapy.
• Upconversion nanocrystals (UCNs) offer potential for simultaneous temperature sensing and photothermal agent delivery.
• Limitations of UCNs include weak luminescence and the need for multiple laser excitations, hindering their therapeutic application.

Purpose of the Study:

• To synthesize a nanoprobe (NP) with integrated photothermal conversion and temperature detection capabilities for precise photothermal therapy.
• To enhance the performance of UCNs for improved therapeutic outcomes.

Main Methods:

• NaYF4:Yb3+,Er3+,Nd3+ upconversion nanocrystals were synthesized and modified with PL-PEG-NH2, IR-806 dye, and folic acid.
• IR-806 dye molecules acted as molecular antennas on the NP surface for enhanced near-infrared photon absorption and energy conversion.
• The synthesized NPs were characterized for their photothermal and temperature-sensing properties.

Main Results:

• 808 nm laser irradiation enhanced upconversion luminescence via Nd ion absorption and IR-806 FRET.
• A luminescence ratio (520/545 nm) accurately monitored NP temperature.
• Significant temperature increase and efficient tumor cell killing were observed due to the photothermal effect.
• NPs demonstrated successful distribution to tumor cells and tissues in vivo, leading to tumor necrosis.

Conclusions:

• Precision photothermal therapy is achievable through highly efficient near-infrared light absorption and accurate temperature monitoring.
• The developed nanoprobes show promise for tumor treatment and biological microzone temperature detection.