Core@shell Fe₃O₄@Mn²⁺-doped NaYF₄:Yb/Tm nanoparticles for triple-modality T₁/T₂-weighted MRI and NIR-to-NIR upconversion luminescence imaging agents

Dual-Mode Fluorescence and Magnetic Resonance Imaging Nanoprobe Based on Aromatic Amphiphilic Copolymer Encapsulated CdSe@CdS and Fe3O4

“…Furthermore, the transverse 1/ T 2 relaxation rates of the QD/Fe 3 O 4 /amPEN nanoprobes in deionized water related to the Fe concentrations were shown in Figure D. It is clear that a linear relationship is detected between relaxation rates and Fe concentrations, and the relaxation value is up to 65.2 mM –1 s –1 , which is much larger than that of the recently reported dual functional MRI nanoprobes, , demonstrating that the synthesized QD/Fe 3 O 4 /amPEN nanospheres can be served as efficient T 2 -weighted MRI probe.…”

Iron Oxide-Based Magneto-Optical Nanocomposites for In Vivo Biomedical Applications

“…One practical application of photon up-conversion is the feasibility of NIR excitation to generate emission in either the visible or NIR region, thus significantly improving the depth-profiling in optical imaging [ 52 ]. A growing interest in the use of up-conversion nanoparticles (UCNPs) in bioimaging is due to their up-conversion property, providing higher signal-to-noise ratios, deeper tissue penetration, low auto-florescence, and lower photodamage than conventional luminescent probes [ 53 ]. The application of UCNPs in bioimaging and their clinical trials are still restricted because of their low up-conversion luminescence (UCL) efficiency in vivo.…”

“…Recently, Fe 3 O 4 @Mn 2+ -doped NaYF 4 : Yb/Tm nanoparticles (NPs) were synthesized as promising imaging agents for NIR-to-NIR UCL and T 1 /T 2 -weighted MRI [ 53 ]. IONPs (Fe 3 O 4 ) were used as seeds and covered with a NIR active shell of Mn 2+ -doped NaYF 4 : Yb/Er NPs using a facile hydrothermal method.…”

Multifunctional NaYF4:Nd/NaDyF4 nanocrystals as a multimodal platform for NIR-II fluorescence and magnetic resonance imaging

“…In previous studies, MRI, as a biological imaging method, provides more relative position details than other imaging methods, and can complement the biological information provided by other imaging methods. [42][43][44][45][46] Some rare earth elements (i.e., Gd 3+ and Dy 3+ ) as MRI contrast agents can be co-doped into upconversion NCs to achieve high tissue penetration depth utilizing multi-modal bioimaging. 12,47,48 Among them, Dy 3+ ions have the advantages of a short electron relaxation time ($0.5 ps) and large magnetic moment (10.6 m B ) and are considered to be an ideal contrast agent for T 2 -weighted MRI.…”