Silica-coated LiYF:Yb, Tm upconverting nanoparticles are non-toxic and activate minor stress responses in mammalian cells.

Lanthanide-doped upconverting nanoparticles (UCNPs) are ideal candidates for use in biomedicine. The interaction of nanomaterials with biological systems determines whether they are suitable for use in living cells. In-depth knowledge of the nano-bio interactions is therefore a pre-requisite for the development of biomedical applications.

Janus Micromotors for Photophoretic Motion and Photon Upconversion Applications Using a Single Near-Infrared Wavelength.

External stimuli can trigger changes in temperature, concentration, and momentum between micromotors and the medium, causing their propulsion and enabling them to perform different tasks with improved kinetic efficiencies. Light-activated micromotors are attractive systems that achieve improved motion and have the potential for high spatiotemporal control. Photophoretic swarming motion represents an attractive means to induce micromotor movement through the generation of temperature gradients in the medium, enabling the micromotors to move from cold to hot regions.

Achieving photostability in dye-sensitized upconverting nanoparticles and their use in Fenton type photocatalysis.

Dye sensitization is a promising approach to enhance the luminescence of lanthanide-doped upconverting nanoparticles. However, the poor photostability of near-infrared dyes hampers their use in practical applications. To address this, commercial IR820 was modified for improved photostability and covalently bonded to amine-functionalized silica-coated LnUCNPs.

The role of lanthanide luminescence in advancing technology.

Our society is indebted to the numerous inventors and scientists who helped bring about the incredible technological advances in modern society that we all take for granted. The importance of knowing the history of these inventions is often underestimated, although our reliance on technology is escalating. Lanthanide luminescence has paved the way for many of these inventions, from lighting and displays to medical advancements and telecommunications.

Combining Pr-Doped Nanoradiosensitizers and Endogenous Protoporphyrin IX for X-ray-Mediated Photodynamic Therapy of Glioblastoma Cells.

Glioblastoma multiforme is an aggressive type of brain cancer with high recurrence rates due to the presence of radioresistant cells remaining after tumor resection. Here, we report the development of an X-ray-mediated photodynamic therapy (X-PDT) system using NaLuF:25% Pr radioluminescent nanoparticles in conjunction with protoporphyrin IX (PPIX), an endogenous photosensitizer that accumulates selectively in cancer cells. Conveniently, 5-aminolevulinic acid (5-ALA), the prodrug that is administered for PDT, is the only drug approved for fluorescence-guided resection of glioblastoma, enabling dual detection and treatment of malignant cells.

Cooperative Sensitization Upconversion in Solution Dispersions of Co-Crystal Assemblies of Mononuclear Yb and Eu Complexes.

Lanthanide upconversion luminescence in nanoparticles has prompted continuous breakthroughs in information storage, temperature sensing, and biomedical applications, among others. Achieving upconversion luminescence at the molecular scale is still a critical challenge in modern chemistry. In this work, we explored the upconversion luminescence of solution dispersions of co-crystals composed of discrete mononuclear Yb(DBM) Bpy and Eu(DBM) Bpy complexes (DBM: dibenzoylmethane, Bpy: 2,2'-bipyridine).

Biomolecules incorporated in halide perovskite nanocrystals: synthesis, optical properties, and applications.

Halide perovskite nanocrystals (HPNCs) have emerged at the forefront of nanomaterials research over the past two decades. The physicochemical and optoelectronic properties of these inorganic semiconductor nanoparticles can be modulated through the introduction of various ligands. The use of biomolecules as ligands has been demonstrated to improve the stability, luminescence, conductivity and biocompatibility of HPNCs.

Upconversion Luminescence through Cooperative and Energy-Transfer Mechanisms in Yb -Metal-Organic Frameworks.

Lanthanide-doped metal-organic frameworks (Ln-MOFs) have versatile luminescence properties, however it is challenging to achieve lanthanide-based upconversion luminescence in these materials. Here, 1,3,5-benzenetricarboxylic acid (BTC) and trivalent Yb ions were used to generate crystalline Yb-BTC MOF 1D-microrods with upconversion luminescence under near infrared excitation via cooperative luminescence. Subsequently, the Yb-BTC MOFs were doped with a variety of different lanthanides to evaluate the potential for Yb -based upconversion and energy transfer.

On the photostability and luminescence of dye-sensitized upconverting nanoparticles using modified IR820 dyes.

Dye sensitization is a promising route to enhance luminescence from lanthanide-doped upconverting nanoparticles (LnUCNPs) by improving the photon harvesting capability of LnUCNPs through the use of dye molecules, characterized by higher absorption coefficients. The literature does not fully address the poor photostability of NIR dyes, hindering solution-based applications. The improvements achieved by dye-sensitized LnUCNPs are usually obtained by comparison with non-dye sensitized LnUCNPs.

Cytotoxicity and Genotoxicity of Azobenzene-Based Polymeric Nanocarriers for Phototriggered Drug Release and Biomedical Applications.

Drug nanoencapsulation increases the availability, pharmacokinetics, and concentration efficiency for therapeutic regimes. Azobenzene light-responsive molecules experience a hydrophobicity change from a polar to an apolar tendency by photoisomerization upon UV irradiation. Polymeric photoresponse nanoparticles (PPNPs) based on azobenzene compounds and biopolymers such as chitosan derivatives show prospects of photodelivering drugs into cells with accelerated kinetics, enhancing their therapeutic effect.

Lifetime of the H Electronic State in Tm-Doped Upconverting Nanoparticles for NIR Nanothermometry.

Emission bands from thermally coupled states in lanthanide-doped nanoparticles have been studied for ratiometric nanothermometry in biological applications. Unfortunately certain factors such as water absorption distort the intensity, limiting the accuracy of ratiometric nanothermometry. However, the decay time of such states does not suffer from such distortions.

Energy Migration Control of Multimodal Emissions in an Er -Doped Nanostructure for Information Encryption and Deep-Learning Decoding.

Modulating the emission wavelengths of materials has always been a primary focus of fluorescence technology. Nanocrystals (NCs) doped with lanthanide ions with rich energy levels can produce a variety of emissions at different excitation wavelengths. However, the control of multimodal emissions of these ions has remained a challenge.

Low-Temperature-Induced Controllable Transversal Shell Growth of NaLnF Nanocrystals.

Highly controllable anisotropic shell growth is essential for further engineering the function and properties of lanthanide-doped luminescence nanocrystals, especially in some of the advanced applications such as multi-mode bioimaging, security coding and three-dimensional (3D) display. However, the understanding of the transversal shell growth mechanism is still limited today, because the shell growth direction is impacted by multiple complex factors, such as the anisotropy of surface ligand-binding energy, anisotropic core-shell lattice mismatch, the size of cores and varied shell crystalline stability. Herein, we report a highly controlled transversal shell growth method for hexagonal sodium rare-earth tetrafluoride (β-NaLnF) nanocrystals.

Investigating the reactive oxygen species production of Rose Bengal and Merocyanine 540-loaded radioluminescent nanoparticles.

Radioluminescent nanomaterials have garnered significant attention in the past decade due to their potential to perform X-ray mediated photodynamic therapy (X-PDT). Many of these materials are assumed to produce singlet oxygen based on a single assay. Herein we demonstrate that multiple assays are required to confidently determine whether singlet oxygen or other reactive oxygen species are being produced through type I or type II PDT mechanisms.

On a local (de-)trapping model for highly doped Pr radioluminescent and persistent luminescent nanoparticles.

Trivalent praseodymium exhibits a wide range of luminescent phenomena when doped into a variety of different materials. Herein, radioluminescent NaLuF4:20%Pr3+ nanoparticles are studied. Four different samples of this composition were prepared ranging from 400-70 nm in size.

The Key Role of Intrinsic Lifetime Dynamics from Upconverting Nanosystems in Multiemission Particle Velocimetry.

Evaluation of particle dynamics at the nano- and microscale poses a challenge to the development of novel velocimetry techniques. Established optical methods implement external or internal calibrations of the emission profiles by varying the particle velocity and are limited to specific experimental conditions. The proposed multiemission particle velocimetry approach aims to introduce a new concept for a luminescent probe, which guarantees accurate velocity measurements at the microscale, independent of the particle concentration or experimental setup, and without need for calibration.

Evaluation of Lanthanide-Doped Upconverting Nanoparticles for and Applications.

Because of their unique physicochemical properties, lanthanide-doped upconverting nanoparticles (Ln-UCNPs) have exceptional potential for biological applications. However, the use in biological systems is hampered by the limited understanding of their bionano interactions. Our multidisciplinary study has generated these insights through in-depth and quantitative analyses.

Wavelength-Selective Nonlinear Imaging and Photo-Induced Cell Damage by Dielectric Harmonic Nanoparticles.

We introduce a nonlinear all-optical theranostics protocol based on the excitation wavelength decoupling between imaging and photoinduced damage of human cancer cells labeled by bismuth ferrite (BFO) harmonic nanoparticles (HNPs). To characterize the damage process, we rely on a scheme for temperature monitoring based on upconversion nanoparticles: by spectrally resolving the emission of silica coated NaGdF4:Yb/Er nanoparticles in close vicinity of a BFO HNP, we show that the photointeraction upon NIR-I excitation at high irradiance is associated with a temperature increase >100 °C. The observed laser-cell interaction implies a permanent change of the BFO nonlinear optical properties, which can be used as a proxy to read out the outcome of a theranostics procedure combining imaging at 980 nm and selective cell damage at 830 nm.

Cellular Uptake, Cytotoxicity and Trafficking of Supported Lipid-Bilayer-Coated Lanthanide Upconverting Nanoparticles in Alveolar Lung Cancer Cells.

An understanding of the cellular uptake and trafficking of nanoparticles is important for the design of efficient nanoparticle-based nanomedicines. Herein we compare the uptake and cytotoxicity of diamond-shape, lanthanide upconverting nanoparticles (LiYF:Tm/Yb UCNPs) with different surface properties. Coating the UCNP with a supported lipid bilayer yielded negligible cytotoxicity on A549 human lung cancer cells, albeit with a lower, but still significant, UCNP uptake compared to oleate-capped and oleate-free UCNPs.

Luminescence dynamics and enhancement of the UV and visible emissions of Tm in LiYF:Yb,Tm upconverting nanoparticles.

To maximize the intrinsic luminescence efficiency of the higher energy emissions of Tm in LiYF:Yb,Tm upconverting nanoparticles, we investigated a specific range of Tm dopant concentrations. Reported to be optimized at 25% Yb, 0.5% Tm, due to the multitude of Tm-to-Tm interactions, the Tm concentration commonly used may not be suitable for strong UV and visible emissions.

Optically Stimulated Nanodosimeters with High Storage Capacity.

In this work we report on the thermoluminescence (TL) and optically stimulated luminescence (OSL) properties of β-Na(Gd,Lu)F:Tb nanophosphors prepared via a standard high-temperature coprecipitation route. Irradiating this phosphor with X-rays not only produces radioluminescence but also leads to a bright green afterglow that is detectable up to hours after excitation has stopped. The storage capacity of the phosphor was found to be (2.

Intrinsic Time-Tunable Emissions in Core-Shell Upconverting Nanoparticle Systems.

Color-tunable luminescence has been extensively investigated in upconverting nanoparticles for diverse applications, each exploiting emissions in different spectral regions. Manipulation of the emission wavelength is accomplished by varying the composition of the luminescent material or the characteristics of the excitation source. Herein, we propose core-shell β-NaGdF : Tm , Yb /β-NaGdF : Tb nanoparticles as intrinsic time-tunable luminescent materials.

Recent insights into upconverting nanoparticles: spectroscopy, modeling, and routes to improved luminescence.

The development of reliable and reproducible synthetic routes that produce monodisperse lanthanide-doped upconverting nanoparticles has resulted in an appreciable need to determine the mechanisms which govern upconversion luminescence at the nanoscale. New experimental and theoretical evidence explicates the quenching phenomena involved in the low luminescence efficiencies. A deeper understanding of the role of surfaces and defects in the quenching mechanisms and the properties of upconverting nanoparticles are of fundamental importance to develop nanomaterials with enhanced luminescence properties.