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Upconversion nanocrystals (UCNs) display near‐infrared (NIR)‐responsive photoluminescent properties for NIR imaging and drug delivery. The development of effective strategies for UCN integration with other complementary nanostructures for targeting and drug conjugation is highly desirable. This study reports on a core/shell‐based theranostic system designed by UCN integration with a folate (FA)‐conjugated...
Optogenetics is an emerging powerful tool to investigate workings of the nervous system. However, the use of low tissue penetrating visible light limits its therapeutic potential. Employing deep penetrating near‐infrared (NIR) light for optogenetics would be beneficial but it cannot be used directly. This issue can be tackled with upconversion nanoparticles (UCNs) acting as nanotransducers emitting...
Light upconversion is a very powerful tool in bioimaging as it can eliminate autofluorescence, increase imaging contrast, reduce irradiation damage, and increase excitation penetration depth in vivo. In particular, triplet–triplet annihilation upconverting (TTA‐UC) nanoparticles and liposomes offer high upconversion efficiency at low excitation power. However, TTA‐UC is quenched in air by oxygen,...
Upconverting nanoparticles show potential applications in the field of photovoltaics and array‐based detection devices. While fluorescence enhancement using interference of incident radiation is well known in Stokes‐shift type systems such as fluorescent dyes; the effect of such interference geometry in nonlinear Anti‐Stokes type emission, such as in upconversion rare earth photophysics is demonstrated...
Near infrared (NIR) light triggered phototherapy including photothermal therapy (PTT) and photodynamic therapy (PDT) affords superior outcome in cancer treatment. However, the reactive oxygen species (ROS) generated by NIR‐excited upconversion nanostructure is limited by the feeble upconverted light which cannot activate PDT agents efficiently. Here, an IR‐808 dye sensitized upconversion nanoparticle...
Plasmonic enhancement induced by metallic nanostructures is an effective strategy to improve the upconversion efficiency of lanthanide‐doped nanocrystals. It is demonstrated that plasmonic enhancement of the upconversion luminescence (UCL) of single NaYF4:Yb3+/Er3+/Mn2+ nanocrystal can be tuned by tailoring scattering and absorption cross sections of gold nanorods, which is synthesized wet chemically...
Enzyme activity is important for metabolism, cell functions, and treating diseases. However, remote control of enzyme activity in deep tissue remains a challenge. This study demonstrates near‐infrared (NIR) light‐regulated enzyme activity in living cells based on upconverting nanoparticles (UCNPs) and a photoactivatable Ru complex. The Ru complex is a caged enzyme inhibitor that can be activated by...
Polyphenol compounds, such as curcumin, rutin, rifampicin, can inhibit Aβ aggregation and decrease reactive oxygen species (ROS), and have received much attention in recent years for Alzheimer's disease (AD) treatment. However, the excess metal ions in amyloid plaque can chelate to polyphenol compounds. It significantly declines the efficacy of polyphenol compounds when used in the clinic. In this...
In article 1701635, by Ute Resch‐Genger, Artur Bednarkiewicz, and co‐workers, Yb3+ and Ho3+ co‐doped core–shell colloidal nanoparticles are synthesized and studied. The obtained nanocrystals were designed to have the same chemical composition, but diverse spatial distribution of dopants. The observed differences shine new light on the photo‐physical behavior of luminescent nanoparticles with tailored...
At the core of luminescence color and lifetime tuning of rare earth doped upconverting nanoparticles (UCNPs), is the understanding of the impact of the particle architecture for commonly used sensitizer (S) and activator (A) ions. In this respect, a series of core@shell NaYF4 UCNPs doped with Yb3+ and Ho3+ ions are presented here, where the same dopant concentrations are distributed in different particle...
Here a multifunctional nanoplatform (upconversion nanoparticles (UCNPs)‐platinum(IV) (Pt(IV))‒ZnFe2O4, denoted as UCPZ) is designed for collaborative cancer treatment, including photodynamic therapy (PDT), chemotherapy, and Fenton reaction. In the system, the UCNPs triggered by near‐infrared light can convert low energy photons to high energy ones, which act as the UV–vis source to simultaneously...
C60 has a special dual function; it can act as both a powerful reactive oxygen species (ROS) producer under UV or visible light and an ROS scavenger in the dark. However, ROS has double‐edged effects in living systems. It is still a great challenge for biomedical application to switch and adjust the two opposite properties of C60 in one system. Herein, UCNP@C60‐pep (UCNP: upconversion nanoparticle,...
Near‐infrared‐light‐mediated optical tweezing of individual upconverting particles has enabled all‐optical single‐cell studies, such as intracellular thermal sensing and minimally invasive cytoplasm investigations. Furthermore, the intrinsic optical birefringence of upconverting particles renders them light‐driven luminescent spinners with a yet unexplored potential in biomedicine. In this work, the...
Lanthanide‐doped upconversion nanoparticles (UCNPs) can convert two or more lower‐energy near‐infrared photons to a single photon with higher energy, which makes them particularly suitable for constructing nanoprobes with large imaging depth and minimal interference of autofluorescence and light scattering from biosamples. Furthermore, they feature excellent photostability, sharp and narrow emissions,...
Ever since the first report of UC‐FRET in 2005, which introduced upconversion (UC) fluorescence into biosensing, imaging and medical applications, it has been growing more and more quickly during the past 15 years. In article number 1905084, Zhihong Liu and co‐workers review the efforts to improve the signal contrast of UC probes and sensors, which have gone beyond the FRET principle.
Engineering a facile and controllable approach to modulate the spectral properties of lanthanide‐doped upconversion nanoparticles (UCNPs) is always an ongoing challenge. Herein, long‐range ordered, distinct two‐dimensional (2D) binary nanoparticle superlattices (BNSLs) composed of NaREF4:Yb/Er (RE = Y and Gd) UCNPs and plasmonic metallic nanoparticles (Au NPs), including AB, AB3, and AB13 lattices,...
It is absolutely imperative for development of material science to adjust upconversion luminescence (UCL) properties of highly doped upconversion nanoparticles (UCNPs) with special optical properties and prominent application prospects. In this work, featuring NaHoF4@NaYbF4 (Ho@Yb) structures, sub‐30 nm core–multishell UCNPs are synthesized with a small NaHoF4 core and varied Gd3+/Yb3+ coexisting...
Upconverting nanoparticles (UCNPs) have been used as optical probes in a great variety of scenarios ranging from cells to animal models. When optically trapped, a single UCNP can be remotely manipulated making possible, for instance, thermal scanning in the surroundings of a living cell. When conventional optics is used, the stability of an optically trapped UCNP is very limited. Its reduced size...
Upconversion nanoparticles (UCNPs) have gone beyond traditional fluorophores in a lot of fields due to the outstanding features such as sharp excitation and emission bands, chemical and photo stability of high quality, low auto fluorescence, and high tissue permeation depth of the near‐infrared irradiation light used for excitation. Conventional UCNPs carrying single/multiple emissions under a single...
Core‐Shell Upconverting Nanocrystals
This cover shows that critical information regarding the interface of core‐shell upconverting nanocrystals can be revealed (cracked sphere in the foreground) by implementing complementary STEM‐based methods with atomic‐scale resolution (inclined plane in the background). Depending on the shell growth conditions, core‐shell upconverting nanocrystals are characterized...
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