Lanthanide-doped Nanoparticles Research Articles

Graphene nanosheet reinforcement of polyurethane nanocomposite for green and sustainable photoluminescence, superhydrophobic, and anticorrosive paint.

A simple and environmentally friendly method was developed for smart and efficient waterborne polyurethane (PUR) paint. Sugarcane bagasse was recycled into reduced graphene oxide nanosheets (rGONSs). Both lanthanide-doped aluminate nanoparticles (LAN; photoluminescent agent, 7-9nm) and rGONSs (reinforcement agent) were integrated into a waterborne polyurethane to produce a novel photoluminescent, hydrophobic, and anticorrosive nanocomposite coating. Using ferrocene-based oxidation under masked circumstances, graphene oxide nanosheets were produced from sugarcane bagasse. The oxidized semicarbazide (SCB) nanostructures were integrated into polyurethane coatings as a drying, anticorrosion, and crosslinking agent. Polyurethane coatings with varying amounts of phosphor pigment were prepared and subsequently applied to mild steel. The produced paints (LAN/rGONSs@PUR) were tested for their hydrophobicity, hardness, and scratch resistance. Commission Internationale de l'éclairage (CIE) Laboratory parameters and photoluminescence analysis established the opacity and colourimetric properties of the nanocomposite coatings. When excited at 365 nm, the luminescent transparent paints emitted a strong greenish light at 517 nm. The anticorrosion characteristics of the coated steel were investigated. The phosphor-containing (11% w/w) polyurethane coatings displayed the most pronounced anticorrosion capability and long-persistent luminosity. The prepared waterborne polyurethane paints were very photostable and durable.

Rare Earth-Doped Nanoparticles for Near-Infrared II Image-Guided Photodynamic Therapy

Rare Earth-Doped Nanoparticles for Near-Infrared II Image-Guided Photodynamic Therapy

Assessing the Effect of Surface Coating on the Stability, Degradation, Toxicity and Cell Endocytosis/Exocytosis of Upconverting Nanoparticles

Lanthanide-doped up-converting nanoparticles (UCNPs) have emerged as promising biomedical tools in recent years. Most research efforts were devoted to the synthesis of inorganic cores with the optimal physicochemical properties. However, the careful design of UCNPs with the adequate surface coating to optimize their biological performance still remains a significant challenge. Here, we propose the functionalization of UCNPs with four distinct types of surface coatings, which were compared in terms of the provided colloidal stability and resistance to degradation in different biological-relevant media, including commonly avoided analysis in acidic lysosomal-mimicking fluids. Moreover, the influence of the type of particle surface coating on cell cytotoxicity and endocytosis/exocytosis was also evaluated. The obtained results demonstrated that the functionalization of UCNPs with poly(isobutylene-alt-maleic anhydride) grafted with dodecylamine (PMA-g-dodecyl) constitutes an outstanding strategy for their subsequent biomedical application, whereas poly(ethylene glycol) (PEG) coating, although suitable for colloidal stability purposes, hinders extensive cell internalization. Conversely, surface coating with small ligand were found not to be suitable, leading to large degradation degrees of UCNPs. The analysis of particle’ behavior in different biological media and in vitro conditions here performed pretends to help researchers to improve the design and implementation of UCNPs as theranostic nanotools.

Recent Advances in Triplet Energy Transfer between Organic Dyes and Lanthanide-Doped Luminescent Nanoparticles

Recent Advances in Triplet Energy Transfer between Organic Dyes and Lanthanide-Doped Luminescent Nanoparticles

Abstract 4147: Chitosan luminescent rare-earth doped nanoparticles as cancer cell tracking for imaging tumors and their immune response

Abstract Background: Cancer is a group of diseases characterized by the unregulated growth of cells, which can be hard to diagnose due to the high false negatives or positives derived from technical and human mistakes.The detection of solid tumors during resection surgery is also a common issue, so contrast agents are used for both cancer diagnosis and tumor visualization during surgery, facilitating the tumor resection procedure. Nevertheless, they cause long-term problems because they accumulate in specific tissues, low penetration, and rapid clearance from the circulation. It is necessary to study new contrast agents that improve tumor detection to address these issues.Here, we synthesized two different kinds of luminescent nanoparticles (LNPs) conjugated with chitosan (Ch) and functionalized with folic acid (FA) for breast cancer detection. We compared in vitro its physicochemical characteristics and effects on the proliferation of cancer cells. Evaluated its impact on the immune system in vivo and implemented a differential imaging process to resemble a refined 3D visualization of cluster cells using Light Sheet Microscopy. Results: Luminescent nanoparticles (LNPs) synthesized by sol-gel method and functionalized with FA using EDC-NHS coupling revealed high-intensity yellow emission at 540 nm wavelength with a quantum yield of ~ 36%. In vitro viability assay at different times with 293T epithelial cells, MDA-MB-231, and T-47D cancer cells demonstrated biocompatibility and high improvement of cellular uptake by LNP functionalized with FA for cancer cells versus normal cells. Light-sheet microscopy analysis of cell-LNP interactions to visualize tagged MDA-MB-231 clusters with LNP/Ch-FA showed positive interactions due to higher stability and adherence. Biodistribution and effects on the immune system by LNP/Ch-FA nanoparticles inoculated in mice were evaluated by flow cytometer analysis. LNP/Ch-FA were well tolerated in vivo. No adverse effects were observed macroscopically. Peripheral blood analysis from animals injected with LNP/Ch-FA after 2 or 6 days of the treatment showed that a single injection of the different NPs did not have any effects on the amount of circulating neutrophils or monocytes in peripheral blood when assessed 2 or 6 days after the injection. With T cells, the core NP induced a significant decrease in circulating T cells (-31%, p=0.045) that seemed specific to the CD4+ T cells (-33%, p=0.0479). However, conjugation of the NP to chitosan prevented this effect. Conclusions: Our work presented significant evidence that could allow a better understanding of LNPs conjugated with Ch and functionalized with FA for possible upcoming clinical applications that could work singly or in synergy with the present detection techniques to boost accuracy and precision for cancer detection without compromise the inmunosystem. Citation Format: Rodrigo Osorio-Arciniega, Eduardo Lucero-Meza, Bonifacio Can-Uc, Israel Rocha-Mendoza, Pierrick G.J. Fournier, Gustavo A Hirata, Patricia Juarez. Chitosan luminescent rare-earth doped nanoparticles as cancer cell tracking for imaging tumors and their immune response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4147.

Immobilization of rare-earth doped aluminate nanoparticles encapsulated with silica into polylactic acid-based color-tunable smart plastic window

An inorganic/organic nanocomposite was used to develop an afterglow and color-tunable smart window. A combination of polylactic acid (PLA) plastic waste as an environmentally-friendly hosting agent, and lanthanide-activated strontium aluminum oxide nanoparticles (SAON) encapsulated with silica nanoparticles (SAON@Silica) as a photoluminescent efficient agent resulted in a smart organic/inorganic nanocomposite. In order to prepare SAON-encapsulated silica nanoparticles (SAON@Silica), the SAON nanoparticles were coated with silica using the heterogeneous precipitation method. By using transmission electron microscopy (TEM), SAON showed a diameter range of 5–12 nm, while the SAON@Silica nanoparticles showed a diameter range of 50–100 nm. In order to ensure the development of a colorless plastic film, a homogeneous dispersion of the phosphorescent Phosphor@Silica nanoparticles throughout the plastic bulk was confirmed. CIE Lab coordinates and luminescence spectra were used to study the color shift characteristics. Under visible light conditions, the plastic films were transparent. The photoluminescent films emitted green light at 525 nm when excited at 375 nm. The hydrophobicity and ultraviolet protection were enhanced without altering the fundamental physico-mechanical performance of the plastic sheet. The current color-tunable plastic can be used in many potential applications, such as warning signs, anti-counterfeiting barcodes, smart windows, and protective apparel.

Tunable X-ray-induced luminescence in lanthanide-doped LaPO4 nanoparticles

X-ray luminescent nanoparticles have gained significant attention as promising tools for implementing multimodal imaging and radiation-based treatments in theragnostics. The intricate comprehension of their properties and the underlying mechanisms driving the conversion of X-rays into light is critical for their success in various applications. LaPO4 nanoparticles doped with various individual luminescence centers, gadolinium (Gd3+), europium (Eu3+), dysprosium (Dy3+), and terbium (Tb3+), were produced via co-precipitation and investigated for their behavior upon X-ray excitation using energies of up to 225 kV. These materials evidenced a radioluminescent response dependent on the dopant concentrations, with emission lines from 300 to 700 nm, providing insights into the luminescence quenching effect in these structures. The luminescent characteristics of the nanoparticles were studied under continuous irradiation, evidencing the materials’ ability to withstand high absorbed doses and preserve their properties. Furthermore, the influence of dopant concentrations on crystallite size and the dependence of luminescence on thermal treatments was investigated. The assessment of nanoparticle stability in aqueous suspension was evaluated over a broad pH range, revealing a tendency of the LaPO4 surface to selectively interact with electropositive species. This insight enhances our comprehension of the colloidal stability of the material, positioning it for extended applications and in vitro evaluations, along with further surface functionalization.

The research progress of X-ray excited lanthanide-doped nanoparticles

X-rays, renowned for their powerful penetration capabilities, are wildly used in medical diagnostics and material sciences. The distinctive electronic configurations of lanthanide-doped nanoparticles result in their unique luminescent properties. In this review, we first discussed the luminescent mechanism of X-ray-activated lanthanide nanomaterials, including conversion, transport, and luminescence. We then provide a comprehensive summary of the design strategies for lanthanide-doped nanoparticles, the selection of suitable host matrices, choosing the right lanthanide elements, optimizing structural configurations, and employing state-of-the-art synthesis methods. Finally, we highlight the applications of these nanoparticles in fields such as biosensing, photodynamic therapy, optical data storage and time-gated imaging, while also delving into the prospects and challenges associated with these nanoparticles.

Dual heterogeneous interfaces enhance X-ray excited persistent luminescence for low-dose 3D imaging

Lanthanide-doped fluoride nanoparticles (NPs) showcase adjustable X-ray-excited persistent luminescence (XEPL), holding significant promise for applications in three-dimensional (3D) imaging through the creation of flexible X-ray detectors. However, a dangerous high X-ray irradiation dose rate and complicated heating procedure are required to generate efficient XEPL for high-resolution 3D imaging, which is attributed to a lack of strategies to significantly enhance the XEPL intensity. Here we report that the XEPL intensity of a series of lanthanide activators (Dy, Pr, Er, Tm, Gd, Tb) is greatly improved by constructing dual heterogeneous interfaces in a double-shell nanostructure. Mechanistic studies indicate that the employed core@shell@shell structure could not only passivate the surface quenchers to lower the non-radiative relaxation possibility, but also reduce the interfacial Frenkel defect formation energy leading to increase the trap concentration. By employing a NPs containing flexible film as the scintillation screen, the inside 3D electrical structure of a watch was clearly achieved based on the delayed XEPL imaging and 3D reconstruction procedure. We foresee that these findings will promote the development of advanced X-ray activated persistent fluoride NPs and offer opportunities for safer and more efficient X-ray imaging techniques in a number of scientific and practical areas.

Short-wave Infrared Photoluminescence Lifetime Mapping of Rare-Earth Doped Nanoparticles Using All-Optical Streak Imaging.

The short-wave infrared (SWIR) photoluminescence lifetimes of rare-earth doped nanoparticles (RENPs) have found diverse applications in fundamental and applied research. Despite dazzling progress in the novel design and synthesis of RENPs with attractive optical properties, existing optical systems for SWIR photoluminescence lifetime imaging are still considerably restricted by inefficient photon detection, limited imaging speed, and low sensitivity. To overcome these challenges, SWIR photoluminescence lifetime imaging microscopy using an all-optical streak camera (PLIMASC) is developed. Synergizing scanning optics and a high-sensitivity InGaAs CMOS camera, SWIR-PLIMASC has a 1D imaging speed of up to 138.9kHz in the spectral range of 900-1700nm, which quantifies the photoluminescence lifetime of RENPs in a single shot. A 2D photoluminescence lifetime map can be acquired by 1D scanning of the sample. To showcase the power of SWIR-PLIMASC, a series of core-shell RENPs with distinct SWIR photoluminescence lifetimes is synthesized. In particular, using Er3+ -doped RENPs, SWIR-PLIMASC enables multiplexed anti-counterfeiting. Leveraging Ho3+ -doped RENPs as temperature indicators, this system is applied to SWIR photoluminescence lifetime-based thermometry. Opening up a new avenue for efficient SWIR photoluminescence lifetime mapping, this work is envisaged to contribute to advanced materials characterization, information science, and biomedicine.

Electrospinning of glass nanofibers to roughen a waterborne polyurethane coating toward smart applications

Polyurethane (PU) coating bulk was reinforced with electrospun glass nanofibers (GNF) and nanoparticles of lanthanide-doped strontium aluminate (NLSA) to produce mechanically reliable long-lasting photoluminescent and photochromic smart products. Transparent smart coatings of GNF@PU were prepared by the physical integration of lanthanide-doped strontium aluminate nanoparticles. The transparent appearance of GNF@PU was found to shift to green when exposed to ultraviolet light as proved by spectral examinations using photoluminescence and CIE Lab parameters. Fluorescence emission with instantaneous reversibility was monitored for GNF@PU hybrids with trace amounts of NLSA. Afterglow photoluminescence with slow reversibility was observed at higher phosphor concentrations in the GNF@PU hybrids. The coating hybrids revealed an emission band at 517 nm when excited at 365 nm. Transmission electron microscopic (TEM) analysis of the morphological properties of NLSA and GNF showed diameters of 8–12 nm and 75–250 nm, respectively. After being fabricated by electrospinning technique, GNF were incorporated into polyurethane coatings as a roughening agent. X-ray fluorescence (XRF), energy-dispersive X-ray (EDX), and scanning electron microscope (SEM) were used to investigate the morphological features of GNF and smart coatings of GNF@PU. Scratch resistance of smart coatings was found to be higher than that of NLSA-free polyurethane control sample. Both of hydrophobicity and UV resistance improved with an increase in NLSA content.

Recent Advances in Functional Materials for Optical Data Storage.

In the current data age, the fundamental research related to optical applications has been rapidly developed. Countless new-born materials equipped with distinct optical properties have been widely explored, exhibiting tremendous values in practical applications. The optical data storage technique is one of the most significant topics of the optical applications, which is considered as the prominent solution for conquering the challenge of the explosive increase in mass data, to achieve the long-life, low-energy, and super high-capacity data storage. On this basis, our review outlines the representative reports for mainly introducing the functional systems based on the newly established materials applied in the optical storage field. According to the material categories, the representative functional systems are divided into rare-earth doped nanoparticles, graphene, and diarylethene. In terms of the difference of structural features and delicate properties among the three materials, the application in optical storage is comprehensively illustrated in the review. Meanwhile, the potential opportunities and critical challenges of optical storage are also discussed in detail.

Color tunable luminescence in ThO2:Er3+,Yb3+ nanocrystals: a promising new platform for upconversion.

Lanthanide-doped luminescent nanoparticles are an appealing system for many applications in the area of biomedical, solar cell, thermometry, anti-counterfeiting, etc. due to their sensitivity, reliability, high photochemical stability, and high optical transparency in the visible-NIR range. A color-tunable upconversion-luminescence (UCL) in a new low phonon energy ThO2 host based on modulating sensitizer concentration has been realized in this work and it may work as a potential candidate to replace corrosive and toxic fluoride based hosts in the future. Er3+-Yb3+ co-doped thoria nanoparticles were prepared using a gel combustion route and their structural and luminescence properties were determined as a function of the Yb3+ concentration. Phonon dispersion measurements have established the dynamic structural stability of the thoria nanoparticles. Density functional theory (DFT) was used to calculate the defect formation energy, highlighting the feasibility of dual ion (Er3+ and Yb3+) doping in thoria. The morphology and average size of the doped thoria was studied using high resolution transmission electron microscopy (HRTEM), and any defects evolving as a result of aliovalent doping were probed using positron annihilation lifetime spectroscopy (PALS). With 980 nm laser excitation, the nanothoria emits green and near-red light. A significant enhancement of the red-to-green intensity ratio of Er3+ ions in nanothoria was observed with an increase in Yb3+ concentration which resulted in beautiful color tunability from green to yellow light in going from lower (up to ∼5 mol%) to higher (10 and 15 mol%) Yb3+ concentration. The power dependence and the dynamics of the upconverted emission confirm the existence of two-photon upconversion processes for the green and red emissions.

Vacuum-assisted colossal enhancement of up-conversion luminescence of lanthanide-doped nanoparticles upon NIR laser irradiation – a new strategy for phosphor development

Permanent enhancement (by 2 orders of magnitude) of up-conversion luminescence via localized crystal growth, induced by NIR laser irradiation under vacuum conditions. This effect is caused by vacuum-enhanced light-to-heat conversion efficiency.

Effect of –OH on the thermal enhancement properties of NIR-II lanthanide-doped nanoparticles in water

The –OH group plays a key role in the thermal enhancement effect of nanoparticles (NPs). By separately introducing LiCl and D2O into aqueous solutions, we demonstrated how the blue shift and –OH content affect the thermal enhancement factor of NPs.

Multi-color tunable luminescence of SrMoO4: Tb3+, Eu3+ nanophosphors for dual-mode temperature monitoring and multi-dimensional high secure anti-counterfeiting

New lanthanide-doped nanoparticles with unique optical characterisics are highly desirable for non-contact thermal sensing and advanced optical anticounterfeiting. The fluorescence intensity ratio (FIR) nanothermometers with higher relative temperature sensitivity (Sr) offer several advantages over traditional contact-based temperature sensors, including high sensitivity, fast response times, and non-invasive measurement. Herein, we describe the synthesis of nanocrystalline SrMoO4:RE3+ (RE3+= Tb3+ and Eu3+) using co-precipitation method for various optical applications, such as temperature sensing and anti-counterfeiting. These phosphors nanoparticle emit multi-colors by varying the percentage of Eu3+ and Tb3+ ions incorporated into SrMoO4. The maximum absolute sensitivity for multi-mode non-contact temperature measurement based on FIR and the distinct thermal behaviour of Eu3+ and Tb3+ ions was reached at 0.055 K−1. The maximum relative sensitivity is reached at 1.8 % K−1, with a minimum temperature resolution δT of 0.043 K at 300 K and maximum δT of 0.272 K. The developed nanophosphors emit green light when it doped Tb3+ and emit red light when it doped with Eu3+, and both demonstrate distinct changes in their response to temperature variations. The color change with temperature elucidates a real base for potential application in advanced anti-counterfeiting. The co-precipitation method we used to synthesize the nanophosphors is easy to scale up for industrial applications. So, the developed nanophosphors with multicolor emissions is of scientific and technological relevence.

(Invited) Manipulating Light Emission from Rare Earth Doped Nanoparticles for Applications in Theranostics

Luminescent nanomaterials that can be excited, as well as emit, in the near-infrared (NIR) have been investigated for use in a plethora of applications including nanomedicine, nanoelectronics, biosensing, bioimaging, photovoltaics, photocatalysis, etc. The use of NIR light for excitation mitigates some of the drawbacks associated with high-energy (UV or blue) excitation, for example, little to no background autofluorescence from the specimen under investigation as well as no incurred photodamage. Moreover, one of the biggest limitations is of course, that of penetration. As such, NIR light can penetrate tissues much better than high-energy light especially when these wavelengths lie within the three biological windows (BW-I: 700-950, BW-II: 1000-1350, BW-III: 1550-1870 nm) where tissues are optically transparent. At the forefront of NIR excited nanomaterials are rare earth doped nanoparticles, which due to their 4f electronic energy states can undergo conventional (Stokes) luminescence and emit in the three NIR biological windows. However, unlike other classes of nanoparticles, they can also undergo a multiphoton process (known as upconversion) where the NIR excitation light is converted to higher energies resulting in anti-Stokes luminescence spanning the UV-visible-NIR regions. Perhaps the biggest impact of such materials would be in the field of disease diagnostics and therapeutics, now commonly referred to as theranostics. Due to the versatility of their optical properties, it now becomes possible to generate high-energy light (UV or blue) in situ to trigger other light activated therapeutic modalities (i.e. drug release) while using the NIR emission for diagnostics (i.e. bioimaging, nanothermometry). Here, we present the synthesis of various NIR excited (and emitting) rare earth doped core/shell (and multishell) nanoparticles and demonstrate how their luminescence properties can be exploited for potential use in diverse biomedical applications.

(Invited) Luminescence Nanothermometers: Using Light to Detect Temperature

Rare earth doped nanoparticles have recently emerged as versatile luminescent probes for a number of biological applications resulting from their interesting photophysical properties. These nanoparticles can be excited with near-infrared (NIR) light, which is a strict requirement for biomedical applications due its light penetration capabilities. Furthermore, rare earth doped nanoparticles possess a multitude of 4f electronic energy states and excitation with NIR light can therefore lead to different excitation mechanisms. For example, following NIR excitation, the nanoparticles can undergo upconversion where multiple emissions are observed with energies higher than the excitation wavelength. Also, they can undergo conventional luminescence where emission at lower energies than the excitation wavelength can be observed (known as downshifted luminescence). Here, we show that it is possible to harness these various emissions (upconverted and downshifted) to design luminescence nanothermometers capable of detecting temperature in living organisms.

A bubble-enhanced lanthanide-doped up/down-conversion platform with tumor microenvironment response for dual-modal photoacoustic and near-infrared-II fluorescence imaging

As an important tumor diagnosis strategy in precision medicine, multimodal imaging has been widely studied. However, the weak imaging signal with low spatial resolution and the constant signal of lack of specific activation severely limit its disease diagnosis. Herein, a bubble-enhanced lanthanide-based up/down-conversion platform with tumor microenvironment response for dual-mode imaging, LDNP@DMSN-Au@CaCO3 nanoparticles (named as LDAC NPs) were successfully developed. Combining the advantages of photoacoustic imaging (PAI) and the second near-infrared window (NIR-II) fluorescence imaging (FI), significantly improved the accuracy of diseases diagnosis. LDAC NPs with flower-like structure were synthesized through the encapsulation of uniform lanthanide-doped nanoparticles (NaYbF4:Ce,Er@NaYF4 named LDNPs) with dendritic mesoporous silica (DMSN). The gold nanoparticles (Au NPs) were then in situ grown on the surface of DMSN and the surface were finally coated with a layer of calcium carbonate (CaCO3). Under the excitation of the 980 nm laser, LDNPs showed strong emission of NIR-II at 1550 nm due to the doping of Ce and Er ions, showcasing excellent spatial resolution and deep tissue penetration characteristics, while the resulting visible light emission (540 nm) enables Au NPs to generate PAI signals with the aid of LDNPs via the fluorescence resonance energy transfer effect. In acidic tumoral environment, CaCO3 layer could produce CO2 microbubbles, and the PAI signals of LDAC NPs could be further enhanced with the generation of CO2 bubbles due to the bubble cavitation effect. Simultaneously, the NIR-II FI of LDAC NPs was self-enhanced with the degradation of the CaCO3. This intelligent nanoparticle with stimulus-activated dual-mode imaging capability holds great promise in future precision diagnostics.

Ultrastrong Infrared Emission at 1460 nm from Lanthanide-Doped Nanoparticles with Interfacial Sensitization.

Fluorescent imaging in the second near-infrared window (NIR-II; 1000-1700 nm) has recently received tremendous attention due to its excellent tissue probing depths and high resolution. Under NIR pumping, lanthanide-doped nanoparticles can emit infrared light covering a wide range of 800-3000 nm which has good potential for NIR-II imaging and detection. However, the low efficiency hinders their application. Here, we report intense infrared emission at 1460 nm from lanthanide-doped core/shell nanoparticles with efficient interfacial sensitization. The emitter Tm3+ ion and the sensitizer Yb3+ and Nd3+ ions are spatially separated in core and shells so that the efficient interfacial energy transfer is established between Tm3+ and Yb3+/Nd3+ ions, while thermal vibration spread of high concentration of Yb3+ ions and cross-relaxation among Tm3+, Yb3+, and Nd3+ ions are suppressed. As a result, the ultrastrong NIR-II emission at 1460 nm is achieved, which is more than 100-times that in classic core/shell nanoparticles doped with Tm3+ (NaYF4:20%Yb,0.5%Tm@ NaYF4).