Tailored lanthanide-doped upconversion nanoparticles and their promising bioapplication prospects

Mesoporous cerium oxide-coated upconversion nanoparticles for tumor-responsive chemo-photodynamic therapy and bioimaging

“…Additionally, UCNPs are energy converters that can transform low-energy photons to high-energy photons and exhibit strong upconversion (UC) uorescence. [52][53][54][55] Compared to downconversion NPs, UCNPs can assimilate NIR light with a relatively high tissue penetration depth. [56][57][58] Under these conditions, upon NIR 980 nm laser irradiation, Yb 3+ and Tm 3+doped UCNPs (NaGdF 4 :Yb,Tm@NaGdF 4 , by coating a homogeneous NaGdF 4 inert layer, the activator is far away from the surface of the NPs, which can considerably inhibit the annihilation of the luminescence caused by the surface defects of the material) can continuously convert NIR light into UV emission, which will trigger a cerium oxide-based photocatalytic reaction to generate an electron-hole (e À -h + ) pair, and efficiently decompose H 2 O and O 2 to hydroxyl radicals (cOH) and superoxide radicals (cO 2 À ), inducing apoptosis in tumor cells.…”

Synthesis, Optical Properties, and Sensing Applications of LaF3:Yb3+/Er3+/Ho3+/Tm3+ Upconversion Nanoparticles

“…In recent years, lanthanide-doped upconversion nanoparticles (UCNPs) have attracted significant attention due to their extensive applications in various fields, such as catalysis, electronics, and biomedicine [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ]. Upconversion (UC) is a nonlinear optical process characterized by the sequential absorption of multiple photons for high-energy anti-Stokes emission.…”

“…Owing to the 4f inner shell configuration of trivalent lanthanide ions, lanthanide-doped UCNPs with abundant and unique energy levels can exhibit numerous distinctive characteristics, including narrow emission bandwidths, long lifetimes, high resistance to photobleaching, large anti-Stokes shifts, superior photostability, and high tissue penetration depths [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 10 , 11 ]. In addition, the intensity and wavelength of UC luminescence can be adjusted by changing the lanthanide dopants and the host matrix [ 1 , 2 , 6 ]. Due to the favorable abovementioned properties, lanthanide-doped UCNPs have immense potential for biological applications [ 1 , 3 , 4 , 7 , 12 ].…”

Optical response of gold and upconversion nanoparticles assembled via DNA interaction

“…Among various types of nanoparticles, gold nanoparticles (AuNPs) have attracted particular interest thanks to their ease of synthesis and their optical, electronic and thermal properties, which enable their application in different fields ranging from biology to nanophotonics 9-12 . Recently, lanthanide-doped NPs have also been employed because of their ability to absorb infrared light and emit photons at higher energies resulting from an internal upconversion process. These upconversion nanoparticles (UCNPs) have superior optical properties, such as sharp emission lines, variable color emission through compositional tuning, long luminescence lifetimes and prolonged photostability 13,14 , all of which represent promising characteristics for energy applications, sensing, multimodal imaging and photodynamic therapy 13,15 . The coupling of particles with plasmonic and fluorescent properties represents an effective way towards hybrid materials with different optical properties [16][17][18][19] .…”