Water-stable NaLuF4-based upconversion nanophosphors with long-term validity for multimodal lymphatic imaging

Area of Science:

• Biomedical Engineering
• Materials Science
• Nanotechnology

Background:

• Multimodal imaging combines strengths of different modalities to overcome individual limitations.
• Upconversion nanoparticles (UCNPs) are promising for bioimaging due to their unique optical properties.

Purpose of the Study:

• To synthesize multifunctional NaLuF(4)-based upconversion nanoparticles (Lu-UCNPs).
• To evaluate Lu-UCNPs as trimodal imaging agents for computed tomography (CT), magnetic resonance (MR), and upconversion luminescence (UCL) imaging.
• To assess the stability and biocompatibility of the synthesized Lu-UCNPs.

Main Methods:

• Facile one-step microemulsion synthesis of lanthanide-doped Lu-UCNPs (Gd(3+), Yb(3+), Er(3+)/Tm(3+)).
• Surface functionalization with sodium glutamate and diethylene triamine pentacetate acid (DTPA) for stability.
• In vitro characterization including transmission electron microscopy (TEM), methyl thiazolyl tetrazolium (MTT) assay, and histological analysis.
• Application in trimodal CT/MR/UCL lymphatic imaging in small animal models.

Main Results:

• Synthesized Lu-UCNPs exhibit high T1-enhancement, bright UCL emissions, and excellent X-ray absorption.
• The nanoparticles demonstrate excellent stability in water for over six months.
• Successful trimodal CT/MR/UCL lymphatic imaging was achieved in small animals.
• In vitro studies confirmed low toxicity of Lu-UCNPs.

Conclusions:

• The developed Lu-UCNPs are effective, stable, and low-toxicity multimodal agents for CT/MR/UCL imaging.
• This nanoparticle platform technology holds promise for developing next-generation multimodal imaging probes.