Recent advances in lanthanide-doped up-conversion probes for theranostics

Abstract

Up-conversion (or anti-Stokes) luminescence refers to the phenomenon whereby materials emit high energy, short-wavelength light upon excitation at longer wavelengths. Lanthanide-doped up-conversion nanoparticles (Ln-UCNPs) are widely used in biomedicine due to their excellent physical and chemical properties such as high penetration depth, low damage threshold and light conversion ability. Here, the latest developments in the synthesis and application of Ln-UCNPs are reviewed. First, methods used to synthesize Ln-UCNPs are introduced, and four strategies for enhancing up-conversion luminescence are analyzed, followed by an overview of the applications in phototherapy, bioimaging and biosensing. Finally, the challenges and future prospects of Ln-UCNPs are summarized.

Silica-coated LiYF4:Yb3+, Tm3+ upconverting nanoparticles are non-toxic and activate minor stress responses in mammalian cells

“…3,4 In particular, UCNPs do not photobleach or photoblink, have long luminescence lifetimes, as well as narrow excitation and emission bands. 1,3–6 Due to their physical and chemical stability, fluoride-based UCNPs are ideal for biomedical applications. 7…”

“…1,2 Among upconversion nanomaterials, lanthanide-doped upconversion nanoparticles (UCNPs) display unique excitation/emission properties. 3,4 In particular, UCNPs do not photobleach or photoblink, have long luminescence lifetimes, as well as narrow excitation and emission bands. 1,[3][4][5][6] Due to their physical and chemical stability, uoride-based UCNPs are ideal for biomedical applications.…”

“…3,4 In particular, UCNPs do not photobleach or photoblink, have long luminescence lifetimes, as well as narrow excitation and emission bands. 1,[3][4][5][6] Due to their physical and chemical stability, uoride-based UCNPs are ideal for biomedical applications. 7 By tailoring the size, morphology, emission/excitation spectrum, and functionalization of the particle surface, UCNPs are optimized for specic functions.…”

Polydopamine-Coated Manganese-Doped Upconversion Nanoparticles as Potential UCL/MRI Dual-Mode Probes

“…3,4 Recently, lanthanide-doped upconversion luminescence nanoparticles, which convert near-infrared (NIR) radiation into visible or UV light, have been identified as next-generation probes for photoluminescence bioimaging. This is due to their superior tissue permeability, 5 photostability and thermal stability, 6,7 low toxicity, and resistance to photobleaching. 8 However, the utility of in vivo optical imaging is hampered by its relatively low spatial resolution, imaging depth, high autofluorescence, and poor tissue penetration.…”

“…Optical imaging, owing to its high precision, sensitivity, rapid response, operational flexibility, and simplicity, has emerged as an essential tool in oncology treatment, cancer research, and disease surveillance. , This technique enables the visualization of living organisms from cellular to animal scales via upconversion luminescence (UCL) imaging. , Recently, lanthanide-doped upconversion luminescence nanoparticles, which convert near-infrared (NIR) radiation into visible or UV light, have been identified as next-generation probes for photoluminescence bioimaging. This is due to their superior tissue permeability, photostability and thermal stability, , low toxicity, and resistance to photobleaching . However, the utility of in vivo optical imaging is hampered by its relatively low spatial resolution, imaging depth, high autofluorescence, and poor tissue penetration .…”