Multifunctional nanoheater based on NaGdF₄:Yb³⁺, Er³⁺ upconversion nanoparticles

Area of Science:

• Nanotechnology
• Materials Science
• Biomedical Engineering

Background:

• Upconversion nanoparticles (UCNPs) are typically integrated into complex nanostructures for multifunctional applications.
• Achieving multifunctionality within a single-phase nanostructure remains a significant challenge.

Purpose of the Study:

• To investigate the potential of small-sized NaGdF(4):Yb(3+), Er(3+) UCNPs for integrated functionalities.
• To explore the simultaneous upconversion luminescence (UCL), temperature sensing, paramagnetic, and photothermal conversion properties of single-phase UCNPs.

Main Methods:

• Synthesis of small-sized NaGdF(4):Yb(3+), Er(3+) UCNPs (~7.5 nm).
• Characterization of UCNPs' optical, thermal, and magnetic properties.
• Investigation of factors influencing photothermal conversion, including Yb(3+) concentration, nanoparticle size, and core/shell structure.

Main Results:

• Small-sized UCNPs exhibit simultaneous UCL, temperature sensing, paramagnetic, and photothermal conversion capabilities.
• Photothermal conversion efficiency is influenced by Yb(3+) concentration, size, and core/shell architecture.
• Active-core/active-shell structures enhance both UCL efficiency and photothermal conversion due to increased absorption.

Conclusions:

• Single-phase UCNPs can achieve multifunctionality, overcoming the need for complex heterogeneous structures.
• These UCNPs show promise for photothermal therapies with integrated real-time imaging and temperature monitoring.
• Optimizing UCNP design, particularly core/shell structures, can enhance therapeutic efficacy.