¹⁸F-Labeled Magnetic-Upconversion Nanophosphors via Rare-Earth Cation-Assisted Ligand Assembly

Abstract

A novel method of rare-earth cation-assisted ligand assembly has been developed to provide upconversion nanophosphors with T(1)-enhanced magnetic resonance (MR), radioactivity, and targeted recognition properties, making these nanoparticles potential candidates for multimodal bioimaging. The process of modifying the surface of the nanophosphors has been confirmed by transmission electron microscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy, proton nuclear magnetic resonance, Fourier-transform infrared spectroscopy, energy-dispersive X-ray analysis, and so on. The versatility of this surface modification approach for incorporating functional molecules and fabricating fluorine-18-labeled magnetic-upconversion nanophosphors as multimodal bioprobes has been demonstrated by targeted cell imaging, in vivo upconversion luminescence, MR imaging, and positron emission tomography imaging of whole-body small animals.

Upconversion nanoparticle-mediated photodynamic therapy induces THP-1 macrophage apoptosis via ROS bursts and activation of the mitochondrial caspase pathway

“…10 However, a drawback of conventional therapy is the requirement of direct illumination of the tissue by either visible (VIS) or ultraviolet (UV) light to excite the photosensitizers, which have limited penetration depth due to both the absorption and scattering of light by biological tissues, thereby resulting in ineffective therapeutic effects. 11,12 The use of near-infrared (NIR) light in PDT can afford greater penetration depths than that of VIS light because the absorbance for most biomolecules reaches a minimum in the NIR window (700-1,100 nm), 13 and the usefulness of the upconversion nanoparticles (UCNPs) that can convert NIR light to VIS light for noninvasive imaging of deep tissues, drug delivery, and PDT has been shown. [14][15][16][17][18][19][20] In this study, we loaded a commonly used second-generation photosensitizer, chlorin e6 (Ce6), onto silica-coated upconversion nanoparticles to form a supramolecular UCNPs-Ce6 complex used for NIR light-induced PDT of THP-1 macrophages, and we subsequently determined whether UCNPs-Ce6-mediated PDT induced apoptosis through the mitochondrial caspase pathway via ROS bursts, mitochondrial permeability transition pore (MPTP) opening, mitochondrial membrane potential (MMP) depolarization, and mitochondrial dysfunction in vitro.…”

Molecular Imaging with 68Ga Radio-Nanomaterials: Shedding Light on Nanoparticles

“…Moreover, the high X-ray attenuation of Lanthanide elements has been exploited for the use of UCNPs as CT contrast agents [145,146]. Finally, 18 F-labeled UCNPs were synthesized for PET imaging [147].…”

Upconversion nanoparticle as a theranostic agent for tumor imaging and therapy

“…80 The Gd 3þ relaxivity values increased from 3.0 to 7.2 mM À1 s À1 with decreased particle size. The relaxivity of the 2.5 nm nanoparticles was almost twice than that of the clinical Gd-DTPA (Magnevist [92][93][94][95] In addition, directly introducing Gd 3þ95 and modifying with gadopentetic acid (Gd-DTPA) 96 onto the UCNP surface were also proposed for T 1 -weighted MRI.…”