WebJunction Course Catalog

In-depth Analysis of UCNPs Core Application Areas

Bio-imaging: From single-mode to multi-modal precision imaging

Deep in vivo imaging: UCNPs use near-infrared (NIR, such as 980 nm or optimized 915 nm) excitation light to penetrate biological tissues to a depth of several centimeters, which is significantly better than traditional visible light-excited fluorescent probes (penetration is only at the millimeter level). For example, NaYbF₄:Tm@NaGdF₄ core-shell structure UCNPs achieve high-resolution imaging of the liver and spleen in living mice, and are targeted after modification with citric acid ligands. It is worth noting that UCNPs excited at 800 nm can reduce thermal damage caused by water molecule absorption, and the penetration depth is increased to 25 mm, providing a new solution for deep tumor imaging.

Multimodal imaging synergistic technology: Through rare earth ion doping, UCNPs can be used as MRI contrast agents (relaxation rate up to 5.60 s⁻¹·mM⁻¹) and fluorescent probes at the same time, such as NaGdF₄:Yb/Er/Tm system combined with SPECT/CT technology to achieve simultaneous visualization of anatomical structure and metabolic function. In addition, ¹⁸F-labeled UCNPs (such as cit-NPs) can integrate PET/MRI/UCL trimodal imaging, with both sensitivity and spatial resolution, suitable for multi-level detection from cells to living bodies.

Nanoscale temperature measurement: from macro to super-resolution thermal imaging

The luminescence intensity ratio (FIR) of upconverting nanoparticles (UCNPs) is highly sensitive to temperature, especially using the ²H₁₁/₂ and ⁴S₃/₂ thermal coupling energy levels of Er³⁺ (energy level difference ~800 cm⁻¹), which can monitor local temperature changes in cells at the nanoscale (<100 nm). For example, the CaF2:Yb/Er@NaGdF4 core-shell structure uses super-resolution microscopy to achieve accurate temperature measurement of tumor metabolic hotspots (such as mitochondria) with a sensitivity of 0.5°C, providing tools for thermal management of electronic devices or research on abnormal cancer metabolism. In addition, Tm³⁺-doped UCNPs (such as Y₂O₃:Yb/Tm) have a smaller energy level difference (~315 cm⁻¹) and show higher temperature measurement accuracy in the low temperature range (25-45°C), which is suitable for real-time temperature feedback in photothermal therapy.

Cancer Theranostics: From Basic Research to Clinical Transformation

Integration of Diagnosis and Treatment Functions: Single-particle UCNPs can achieve imaging and treatment at the same time. For example, the NaYF4:Yb/Er@NaGdF4 core-shell structure is loaded with photosensitizer Bengal red (RBHA) and platinum drug (Pt(IV)). Under 980 nm excitation, the ultraviolet light emitted by UCNPs activates RBHA to produce reactive oxygen species (ROS), while releasing Pt(IV) for chemotherapy, and the tumor inhibition rate in mice is increased to 82%.

Targeted and precise delivery: UCNPs modified with antibodies (such as anti-ErbB2) or functionalized with aptamers can specifically recognize tumor markers. For example, UCNPs modified with folic acid are endocytosed by folate receptors, and the targeting efficiency in ovarian cancer models is 6 times higher than that of the unmodified group. The DNA aptamer-guided UCNPs-QDs heterostructure can recognize nucleolin overexpressed on the tumor cell membrane, realizing dual-modality imaging and controlled drug release.

Photodynamic/photothermal synergistic therapy: Optimize photoconversion efficiency through core-shell engineering, such as NaYF4:Yb/Er@Au structure converts NIR light into localized surface plasmon resonance (LSPR), generates high temperature (>50°C) to ablate tumors, and the gold shell layer enhances photothermal stability.

Innovative Expansion of Other Medical Applications

Ultra-high sensitivity immunoassay: UCNPs are used as probes to detect cancer markers (such as CEA), and the signal-to-noise ratio (SNR) is 10 times higher than ELISA. The UCNPs-GNPs system designed by the FRET mechanism can detect human IgG as low as 0.1 nM, with a sensitivity spanning 3 orders of magnitude.

Optogenetic neuromodulation: Tm³⁺-doped UCNPs emit 470 nm blue light, which can accurately activate light-sensitive channel proteins (such as ChR2) and regulate neuronal action potentials, providing a new way to intervene in neurological diseases such as Parkinson's disease.