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Laser lithotripsy mechanisms can cause the chemical decomposition of stone components and the emergence of different end products. However, the potentially toxic end products formed during thulium fiber laser (TFL) lithotripsy of cystine stones have not been sufficiently investigated. The aim of our in vitro study is to analyze the chemical content of the gas products formed during the fragmentation of cystine stone with TFL. Human renal calculi consisting of 100% pure cystine, calcium oxalate monohydrate, or uric acid were fragmented separately with TFL in experimental setups and observed for gas release. After the lithotripsy, only the cystine stones showed gas formation. Gas chromatography-mass spectrometry was used to analyze the gas qualitatively, and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) and X-ray diffraction was used to examine the dried cystine stone fragments. Fragmentation of the cystine stones released free cystine, sulfur, hydrogen sulfide, and carbon disulfide gas. The SEM-EDX and X-ray diffraction analyses revealed that the free cystine in the dried fragments contained 43.1% oxygen, 28.7% sulfur, 16.1% nitrogen, and 12.1% carbon atoms according to atomic weight. The detection of potentially toxic gases after lithotripsy of cystine stones with TFL indicates a risk of in vivo production. Awareness needs to be increased among healthcare professionals to prevent potential inhalation and systemic toxicity for patients and operating room personnel during TFL lithotripsy of cystine stones., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

A "turn-on" photon up conversion nano couple based on NaYF 4 : Yb, Tm UCNPs quenched with MnO 2 nanosheet was developed for the rapid and selective detection of cTnT. Herein, MnO 2 nanosheet hold on the surface of Antibody cTnT (Ab-cTnT) conjugated blue emitting up conversion nanoprobe (λ em at 475 nm), which leads to quenching of fluorescence due to energy transfer from photon up conversion nanoparticles to MnO 2 nanosheets. On introducing cTnT antigen to the system, the energy transfer process is hindered due to strong antigen -antibody interface on the surface. This in turn, influences the nano-couples positions and effectively separates up conversion nanoprobe from MnO 2 nanosheets surface resulting in restriction to energy transfer process enabling fluorescence recovery. The developed probe shows a linear response towards cTnT in the range of 0.16-2.77 ng/mL with a Limit of Detection (LoD) of 0.025 ng/mL. The practical feasibility of the nanoprobe is performed with possible coexisting biomolecules. Biological study in human blood serum samples exhibited sufficient recovery percentage in the range of 92-103 % is obtained., Competing Interests: Declaration of competing interest The author declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Development of efficient portable sensors for accurately detecting biomarkers is crucial for early disease diagnosis, yet remains a significant challenge. To address this need, we introduce the enhanced luminescence lateral-flow assay, which leverages highly luminescent upconverting nanoparticles (UCNPs) alongside a portable reader and a smartphone app. The sensor's efficiency and versatility were shown for kidney health monitoring as a proof of concept. We engineered Er 3+ - and Tm 3+ -doped UCNPs coated with multiple layers, including an undoped inert matrix shell, a mesoporous silica shell, and an outer layer of gold (UCNP@mSiO 2 @Au). These coatings synergistically enhance emission by over 40-fold and facilitate biomolecule conjugation, rendering UCNP@mSiO 2 @Au easy to use and suitable for a broad range of bioapplications. Employing these optimized nanoparticles in lateral-flow assays, we successfully detected two acute kidney injury-related biomarkers─kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL)─in urine samples. Using our sensor platform, KIM-1 and NGAL can be accurately detected and quantified within the range of 0.1 to 20 ng/mL, boasting impressively low limits of detection at 0.28 and 0.23 ng/mL, respectively. Validating our approach, we analyzed clinical urine samples, achieving biomarker concentrations that closely correlated with results obtained via ELISA. Importantly, our system enables biomarker quantification in less than 15 min, underscoring the performance of our novel UCNP-based approach and its potential as reliable, rapid, and user-friendly diagnostics.

In this investigation, we embarked on the synthesis of polyethylene glycol coated NaGdF 4 :Tm 3+ /Yb 3+ upconversion nanoparticles (UCNPs), aiming to assess their utility in enhancing image contrast within the context of swept source optical coherence tomography (OCT) and photo-thermal OCT imaging. Our research unveiled the remarkable UC emissions stemming from the transitions of Tm 3+ ions, specifically the 1 G 4 → 3 H 6 transitions, yielding vibrant blue emissions at 472 nm. We delved further into the UC mechanism, meticulously scrutinizing decay times and the nanoparticles' capacity to convert radiation into heat. Notably, these nanoparticles exhibited an impressive photo-thermal conversion efficiency of 37.5%. Furthermore, our investigations into their bio-compatibility revealed a promising outcome, with more than 90% cell survival after 24 h of incubation with HeLa cells treated with UCNPs. The nanoparticles demonstrated a notable thermal sensitivity of 4.7 × 10 -3 K -1 at 300 K, signifying their potential for precise temperature monitoring at the cellular level., (© 2024 IOP Publishing Ltd.)

Nanomaterials that generate reactive oxygen species (ROS) upon light irradiation have significant applications in various fields, including photodynamic therapy (PDT) that is widely recognized as a highly momentous strategy for the eradication of cancer cells. However, the ROS production rate of photosensitizers, as well as the tumor hypoxia environment, are two major challenges that restrict the widespread application of PDT. In this study, a cancer-thylakoid hybrid membrane-camouflaged thulium oxide nanoparticles (Tm 2 O 3 ) for tumor-homing phototherapy through dual-stage-light-guided ROS generation and oxygen self-supply is developed. Tm 2 O 3 as a type II photosensitizer are viable for NIR-stimulated ROS generation due to the unique energy levels, large absorption cross section, and long lifetime of the 3H4 state of Tm ions. The thylakoid membrane (TK) plays a catalase-like role in converting hydrogen peroxide into oxygen and also acts as a natural photosensitizer that can generate lethal ROS through electron transfer when exposed to light. In addition, fluorescence dye DiR is embedded in the hybrid membrane for in vivo tracing as well as photothermal therapy. Results show that tumors in Tm 2 O 3 @TK-M/DiR group are effectively ablated following dual-stage-light irradiation, highlighting the promising potential of rare-earth element-based type II photosensitizers in various applications., (© 2024 Wiley‐VCH GmbH.)

Purpose: There are limited data on ablation effects of thulium fiber laser (TFL) settings with varying stone composition. Similarly, little is known surrounding the photothermal effects of TFL lithotripsy regarding the chemical and structural changes after visible char formation. We aim to understand the TFL's ablative efficiency across various stone types and laser settings, while simultaneously investigating the photothermal effects of TFL lithotripsy., Materials and Methods: Human specimens of calcium oxalate monohydrate, calcium oxalate dihydrate, uric acid, struvite, cystine, carbonate apatite, and brushite stones were ablated using 13 prespecified settings with the Coloplast TFL Drive. Pre- and postablation mass, ablation time, and total energy were recorded. Qualitative ablative observations were recorded at 1-minute intervals with photographs and gross description. Samples were analyzed with Fourier-transform infrared spectroscopy pre- and postablation and electron microscopy postablation to assess the photothermal effects of TFL., Results: Across all settings and stone types, 0.05 J × 1000 Hz was the best numerically efficient ablation setting. When selected for more clinically relevant laser settings (ie, 10-20 W), 0.2 J × 100 Hz, short pulse was the most numerically efficient setting for calcium oxalate dihydrate, cystine, and struvite stones. Calcium oxalate monohydrate ablated with the best numerical efficiency at 0.4 J × 40 Hz, short pulse. Uric acid and carbonate apatite stones ablated with the best numerical efficiency at 0.3 J × 60 Hz, short pulse. Brushite stones ablated with the best numerical efficiency at 0.5 J × 30 Hz, short pulse. Pulse duration impacted ablation effectiveness greatly with 6/8 (75%) of inadequate ablations occurring in medium or long pulse settings. The average percent of mass lost during ablation was 57%; cystine stones averaged the highest percent mass lost at 71%. Charring was observed in 36/91 (40%) specimens. Charring was most often seen in uric acid, cystine, and brushite stones across all laser settings. Electron microscopy of char demonstrated a porous melting effect different to that of brittle fracture. Fourier-transform infrared spectroscopy of brushite char demonstrated a chemical composition change to amorphous calcium phosphate., Conclusions: We describe the optimal ablation settings based on stone composition, which may guide urologists towards more stone-specific care when using thulium laser for treating renal stones (lower energy settings would be safer for ureteral stones). For patients with unknown stone composition, lasers can be preset to target common stone types or adjusted based on visual cues. We recommend using short pulse for all TFL lithotripsy of calculi and altering the settings based on visual cues and efficiency to minimize the charring, an effect which can make the stone refractory to further dusting and fragmentation.

Exploring materials that can absorb near-infrared (NIR) light to produce reactive oxygen species (ROS) is necessary for many fields. Herein we show that thulium oxide nanoparticles are viable for NIR-stimulated ROS generation. This property may be related to the unique energy levels, large absorption cross section, low fluorescence emission, and ∼10 -3 s lifetime of the 3 H 4 state of Tm ions. We further demonstrate the impact of these nanoparticles on photodynamic therapy (PDT), in which impressive tumor inhibition was recorded after exposure to either a broadband halogen lamp or an 808 nm laser. Our results may provide insight into the areas of photocatalysis, pollution treatment, and fine chemical synthesis.

We report enzyme-powered upconversion-nanoparticle-functionalized Janus micromotors, which are prepared by immobilizing uricase asymmetrically onto the surface of silicon particles, to actively and rapidly detect uric acid. The asymmetric distribution of uricase on silicon particles allows the Janus micromotors to display efficient motion in urine under the propulsion of biocatalytic decomposition of uric acid and simultaneously detect uric acid based on the luminescence quenching effect of the UCNPs modified on the other side of SiO 2 . The efficient motion of the motors greatly enhances the interaction between UCNPs and the quenching substrate and improves the uric acid detection efficiency. Overall, such a platform using uric acid simultaneously as the detected substrate and motion fuel offers considerable promise for developing multifunctional micro/nanomotors for a variety of bioassay and biomedical applications.

Cholesterol is a vital compound in maintenance for human health, and its concentration levels are tightly associated with various diseases. Therefore, accurate monitoring of cholesterol is of great significance in clinical diagnosis. Herein, we fabricated a noncontact biosensor based on photonic crystal-enhanced upconversion nanoparticles (UCNPs) for highly sensitive and interference-free cholesterol detection. By compounding LiErF 4 :0.5%Tm 3+ @LiYF 4 UCNPs with poly(methyl methacrylate) (PMMA) photonic crystals (OPCs), we were able to selectively tune the coupling of the photonic band gap to the excitation field and modulate the upconversion (UC) luminescence intensity, given the unique multi-wavelength excitation property of LiErF 4 :0.5%Tm 3+ @LiYF 4 . A 48.5-fold enhancement of the monochromatic red UC emission was ultimately achieved at 980 nm excitation, ensuring improved detection sensitivity. Based on the principle of quenching of the intense monochromic red UC emission by the oxidation products of 3,3',5,5'-tetramethylbenzidine (TMB) yielded from the cholesterol cascade reactions, the biosensor has a detection limit of 1.6 μM for cholesterol with excellent specificity and stability. In addition, the testing results of the as-designed biosensor in patients are highly consistent with clinical diagnostic data, providing a sensitive, reliable, reusable, interference-free, and alternative strategy for clinical cholesterol detection.

Carbon monoxide (CO) can cause mitochondrial dysfunction, inducing apoptosis of cancer cells, which sheds light on a potential alternative for cancer treatment. However, the existing CO-based compounds are inherently limited by their chemical nature, such as high biological toxicity and uncontrolled CO release. Therefore, a nanoplatform - UmPF - that addresses such pain points is urgently in demand. In this study, we have proposed a nanoplatform irradiated by near-infrared (NIR) light to release CO. Iron pentacarbonyl (Fe(CO) 5 ) was loaded in the mesoporous polydopamine layer that was coated on rare-earth upconverting nanoparticles (UCNPs). The absorption wavelength of Fe(CO) 5 overlaps with the emission bands of the UCNPs in the UV-visible light range, and therefore the emissions from the UCNPs can be used to incite Fe(CO) 5 to control the release of CO. Besides, the catechol groups, which are abundant in the polydopamine structure, serve as an ideal locating spot to chelate with Fe(CO) 5 ; in the meantime, the mesoporous structure of the polydopamine layer improves the loading efficiency of Fe(CO) 5 and reduces its biological toxicity. The photothermal effect (PTT) of the polydopamine layer is highly controllable by adjusting the external laser intensity, irradiation time and the thickness of the polydopamine layer. The results illustrate that the combination of CO gas therapy (GT) and polydopamine PTT brought by the final nanoplatform can be synergistic in killing cancer cells in vitro . More importantly, the possible toxic side effects can be effectively prevented from affecting the organism, since CO will not be released in this system without near-infrared light radiation.

Over the last decade, upconversion nanoparticles (UCNP) have been widely investigated in nanomedicine due to their high potential as imaging agents in the near-infrared (NIR) optical window of biological tissues. Here, we successfully develop active targeted UCNP as potential probes for dual NIR-NIR fluorescence and radioactive-guided surgery of prostate-specific membrane antigen (PSMA)(+) prostate cancers. We designed a one-pot thermolysis synthesis method to obtain oleic acid-coated spherical NaYF 4 :Yb,Tm@NaYF 4 core/shell UCNP with narrow particle size distribution (30.0 ± 0.1 nm, as estimated by SAXS analysis) and efficient upconversion luminescence. Polyethylene glycol (PEG) ligands bearing different anchoring groups (phosphate, bis- and tetra-phosphonate-based) were synthesized and used to hydrophilize the UCNP. DLS studies led to the selection of a tetra-phosphonate PEG (2000) ligand affording water-dispersible UCNP with sustained colloidal stability in several aqueous media. PSMA-targeting ligands ( i.e. , glutamate-urea-lysine derivatives called KuEs) and fluorescent or radiolabelled prosthetic groups were grafted onto the UCNP surface by strain-promoted azide-alkyne cycloaddition (SPAAC). These UCNP, coated with 10 or 100% surface density of KuE ligands, did not induce cytotoxicity over 24 h incubation in LNCaP-Luc or PC3-Luc prostate cancer cell lines or in human fibroblasts for any of the concentrations evaluated. Competitive binding assays and flow cytometry demonstrated the excellent affinity of UCNP@KuE for PSMA-positive LNCaP-Luc cells compared with non-targeted UCNP@CO 2 H. Furthermore, the binding of UCNP@KuE to prostate tumour cells was positively correlated with the surface density of PSMA-targeting ligands and maintained after 125 I-radiolabelling. Finally, a preliminary biodistribution study in LNCaP-Luc-bearing mice demonstrated the radiochemical stability of non-targeted [ 125 I]UCNP paving the way for future in vivo assessments.

Chemotherapy can induce toxicity in the central and peripheral nervous systems and result in chronic adverse reactions that impede continuous treatment and reduce patient quality of life. There is a current lack of research to predict, identify, and offset drug-induced neurotoxicity. Rapid and accurate assessment of potential neuropathy is crucial for cost-effective diagnosis and treatment. Here we report dynamic near-infrared upconversion imaging that allows intraneuronal transport to be traced in real time with millisecond resolution, but without photobleaching or blinking. Drug-induced neurotoxicity can be screened prior to phenotyping, on the basis of subtle abnormalities of kinetic characteristics in intraneuronal transport. Moreover, we demonstrate that combining the upconverting nanoplatform with machine learning offers a powerful tool for mapping chemotherapy-induced peripheral neuropathy and assessing drug-induced neurotoxicity.

In this work we adapt rare-earth-ion-doped NaYF 4 nanoparticles coated with a silicon oxide shell (NaYF 4 :20%Yb,0.2%Tm@SiO 2 ) for biological and medical applications (for example, imaging of cancer cells and therapy at the nano level). The wide upconversion emission range under 980 nm excitation allows one to use the nanoparticles for cancer cell (4T1) photodynamic therapy (PDT) without a photosensitizer. The reactive oxygen species (ROS) are generated by Tm/Yb ion upconversion emission (blue and UV light). The in vitro PDT was tested on 4T1 cells incubated with NaYF 4 :20%Yb,0.2%Tm@SiO 2 nanoparticles and irradiated with NIR light. After 24 h, cell viability decreased to below 10%, demonstrating very good treatment efficiency. High modification susceptibility of the SiO 2 shell allows for attachment of biological molecules (specific antibodies). In this work we attached the anti-human IgG antibody to silane-PEG-NHS-modified NaYF 4 :20%Yb,0.2%Tm@SiO 2 nanoparticles and a specifically marked membrane model by bio-conjugation. Thus, it was possible to perform a selective search (a high-quality optical method with a very low-level organic background) and eventually damage the targeted cancer cells. The study focuses on therapeutic properties of NaYF 4 :20%Yb,0.2%Tm@SiO 2 nanoparticles and demonstrates, upon biological functionalization, their potential for targeted therapy., (Creative Commons Attribution license.)

Photon upconversion of near-infrared (NIR) irradiation into ultraviolet-C (UVC) emission offers many exciting opportunities for drug release in deep tissues, photodynamic therapy, solid-state lasing, energy storage, and photocatalysis. However, NIR-to-UVC upconversion remains a daunting challenge due to low quantum efficiency. Here, we report an unusual six-photon upconversion process in Gd 3+ /Tm 3+ -codoped nanoparticles following a heterogeneous core-multishell architecture. This design efficiently suppresses energy consumption induced by interior energy traps, maximizes cascade sensitizations of the NIR excitation, and promotes upconverted UVC emission from high-lying excited states. We realized the intense six-photon-upconverted UV emissions at 253 nm under 808 nm excitation. This work provides insight into mechanistic understanding of the upconversion process within the heterogeneous architecture, while offering exciting opportunities for developing nanoscale UVC emitters that can be remotely controlled through deep tissues upon NIR illumination., (© 2021. The Author(s).)

Immunohistochemistry (IHC) and immunocytochemistry (ICC) are widely used to identify cancerous cells within tissues and cell cultures. Even though the optical microscopy evaluation is considered the gold standard, the limited range of useful labels and narrow multiplexing capabilities create an imminent need for alternative readout techniques. Laser-induced breakdown spectroscopy (LIBS) enables large-scale multi-elemental analysis of the surface of biological samples, e.g., thin section or cell pellet. It is, therefore, a potential alternative for IHC and ICC readout of various labels or tags (Tag-LIBS approach). Here, we introduce Tag-LIBS as a method for the specific determination of HER2 biomarker. The cell pellets were labeled with streptavidin-conjugated upconversion nanoparticles (UCNP) through a primary anti-HER2 antibody and a biotinylated secondary antibody. The LIBS scanning enabled detecting the characteristic elemental signature of yttrium as a principal constituent of UCNP, thus indirectly providing a reliable way to differentiate between HER2-positive BT-474 cells and HER2-negative MDA-MB-231 cells. The comparison of results with upconversion optical microscopy and luminescence intensity scanning confirmed that LIBS is a promising alternative for the IHC and ICC readout.

The aim of this work is to study the dosimetric properties of tissue-equivalent thulium doped NaMgF 3 neighborites and to determine their possible application as dosimeters in personal dosimetry. In this aspect, radioluminescence (RL) and optically stimulated luminescence (OSL) dosimetric properties of undoped and Tm 3+ -doped NaMgF 3 have been investigated for the first time. Samples were synthesized by solid state reaction and by considering a stoichiometric mixture of pure NaF and MgF 2 reagents. Two emission peaks centered at 460 and 360 nm have been found in the RL emission spectrum of the doped samples, which can be ascribed to the 1 D 2 - 3 F 4 and 1 D 2 - 3 H 6 transitions of Tm 3+ cations, respectively. Maximum OSL emission under blue light stimulation has been found for samples doped with 0.2 mol % of thulium. Furthermore, the OSL signal of this compound depends linearly on dose within the range 0.05-100 Gy. Besides, its OSL signal features satisfactory repeatability and a minimum detectable dose of 0.04 Gy. Finally, it has been found a low fading of the OSL signal of approximately 13% after the first 60 h, after which the OSL response remains constant. The obtained results suggest the feasibility of using this compound as an OSL detector in personal dosimetry., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

A novel multichannel sensor array has been designed using a single, yet multiemissive lanthanide-doped upconversion nanoparticle (UCNP). The energy levels of lanthanide ions gave rise to several emission bands which were exploited as individual sensor elements for the recognition of four important neurotransmitters (NTs): dopamine, norepinephrine, levodopa, and serotonin. At alkaline conditions, the oxidation products of these NTs quenched the fluorescence emissions of UCNPs with different quenching degrees. The resulting fingerprint multichannel emission profiles from NaYF 4 :Yb/Er/Tm UCNPs allowed the discrimination of NTs with excellent accuracy. The recognition was further verified in artificial cerebrospinal fluid, as a complex biological media. We believe that the designed UCNP-based multichannel sensor array offers innovative insights into the discrimination of various chemical signatures using a single measurement.

Metastases from cutaneous squamous cell carcinoma (cSCC) occur in 2%-5% of cases. Surgery is the standard treatment, often combined with adjuvant radiotherapy. Concurrent carboplatin treatment with post-operative radiotherapy may be prescribed, although it has not shown benefit in recent clinical trials in high-risk cSCC patients. The novel high-Z nanoparticle thulium (III) oxide has been shown to enhance radiation dose delivery to brain tumors by specific uptake of these nanoparticles into the cancerous tissue. As the dose-enhancement capacity of thulium oxide nanoparticles following radiotherapy against metastatic cSCC cells is unknown, its efficacy as a radiosensitizer was evaluated, with and without carboplatin. Novel and validated human patient-derived cell lines of metastatic cSCC were used. The sensitivity of the cells to radiation was investigated using short-term proliferation assays as well as clonogenic survival as the radiobiological endpoint. Briefly, cells were irradiated with 125 kVp orthovoltage x-rays (0-6 Gy) with and without thulium oxide nanoparticles (99.9% trace metals basis; 50 µg ml -1 ) or low dose carboplatin pre-sensitization. Cellular uptake of the nanoparticles was first confirmed by microscopy and found to have no impact on short-term cell survival for the cSCC cells, highlighting the biocompatibility of thulium oxide nanoparticles. Clonogenic cell survival assays confirmed radio-sensitization when exposed to thulium nanoparticles, with the cell sensitivity increasing by a factor of 1.24 (calculated at the 10% survival fraction) for the irradiated cSCC cells. The combination of carboplatin with thulium oxide nanoparticles with irradiation did not result in significant further reductions in survival compared to nanoparticles alone. This is the first study to provide in vitro data demonstrating the independent radiosensitization effect of high-Z nanoparticles against metastatic cSCC with or without carboplatin. Further preclinical investigations with radiotherapy plus high-Z nanoparticles for the management of metastatic cSCC are warranted.

Theranostic approach is currently among the fastest growing trends in cancer treatment. It implies the creation of multifunctional agents for simultaneous precise diagnosis and targeted impact on tumor cells. A new type of theranostic complexes was created based on NaYF 4 : Yb,Tm upconversion nanoparticles coated with polyethylene glycol and functionalized with the HER2-specific recombinant targeted toxin DARPin-LoPE. The obtained agents bind to HER2-overexpressing human breast adenocarcinoma cells and demonstrate selective cytotoxicity against this type of cancer cells. Using fluorescent human breast adenocarcinoma xenograft models, the possibility of intravital visualization of the UCNP-based complexes biodistribution and accumulation in tumor was demonstrated.

Gd3+ and Tm3+ doped Prussian blue (Gd/Tm-PB) with high uniformity and dispersibility was synthesized by a facile solvothermal method. The conditions for the synthesis of Gd/Tm-PB were explored. Through the regulation of the ratio of Gd3+/Tm3+, the Gd/Tm-PB particles with the optimal size (about 150-200 nm) and the best fluorescence and photothermal effect were obtained. On the basis of the optimal Gd/Tm-PB, further coated by polydopamine (PDA) functionalized metal-organic frameworks (MOFs), a multifunctional platform Gd/Tm-PB@ZIF-8/PDA for cancer diagnosis and treatment was established. Doxorubicin (DOX) was selected as a drug model and the drug loading of Gd/Tm-PB@ZIF-8/PDA was found to be 81 mg g-1. Cytotoxicity analysis indicated that Gd/Tm-PB@ZIF-8/PDA was highly biocompatible. The DOX release at different pH values and GSH concentrations revealed an excellent pH/GSH-triggered drug release. Through the combination of the near infrared photothermal performance of Gd/Tm-PB, chemo-photothermal therapy can be achieved to further improve the anti-cancer efficiency. In addition, the Gd/Tm-PB@ZIF-8/PDA nanoparticles can be tracked by fluorescence imaging (FOI) and magnetic resonance imaging (MRI). Cell FOI and in vivo MRI experiments showed the potential application of Gd/Tm-PB@ZIF-8/PDA in dual mode imaging guided therapy. In vivo antitumor experiments demonstrated the higher anticancer efficacy of Gd/Tm-PB@ZIF-8/PDA with a combined effect of chemo-photothermal therapy. This work provides a new strategy for nano-drug carriers in the direction of integrated diagnosis and treatment.

Purpose: This work investigates how Yb 3+ concentration affects the luminescent properties of LaNbO 4 nanoparticles for medical imaging applications. Due to the highly transparent optical window for organic tissues in the near infrared region (650-1000 nm), upconversion fluorescence allows near infrared wavelengths to penetrate deeply into tissues, which is useful in biomedical areas such as biodetection, activated phototherapy, and screening., Materials/method: Upconversion nanoparticles based on LaNbO 4 doped with Tm 3+ and Yb 3+ were prepared by the one-step industrial process called Spray Pyrolysis. Samples with different Tm 3+ :Yb 3+ molar ratios (1:4, 1:8 and 1:16) were obtained., Results: The X-ray powder diffractograms of all the samples displayed the typical peaks of a crystalline material (tetragonal phase). Emission bands emerged in the blue, red, and near infrared regions, and they corresponded to the Tm 3+ 1 G 4 → 3 H 6 (475 nm), 1 G 4 → 3 F 4 (650 nm), 3 F 2,3  →  3 H 6 (690 nm), and 3 H 4 → 3 H 6 (803 nm) transitions, which indicated a two-photon absorption process. As for bio-labelling application, the results indicated that Yb 3+ concentration was directly related to signal intensity., Conclusions: The intensity of positive conversion emissions depends directly on Yb 3+ concentration. The bio-labelling tests pointed to the potential application of these materials. The sample containing the highest amount of Yb 3+ provided better results and was easier to detect than the standard sample., Competing Interests: Declaration of competing interest The authors declare no conflict of interests., (Copyright © 2020 Medical University of Bialystok. Published by Elsevier B.V. All rights reserved.)

Photoswitchable drugs are small-molecule optical probes that undergo chromatically selective control of drug efficacy using, most often, UV-visible light. Here we report that luminescence produced by near-infrared stimulation of NaYF4:TmYb nanoparticles can be used for "remote control" of an azobenzene-based photochromic ion channel blocker of neurons in living brain slices.

Y 2 O 3 :Tm 3+ and Li + co-doped Y 2 O 3 :Tm 3+ nanopowders were synthesized using the solution combustion method for possible application in ultraviolet (UV) light dosimetry. X-ray diffraction revealed the crystallite sizes to be in the range 21-44 nm and 30-121 nm using the Scherrer equation and the W-H plot relationship, respectively. Field emission scanning electron microscopy confirmed that, after co-doping with 4 mol% concentration of Li + , the particles were spherical in nature with an average size of ~30 nm. Fourier transformed infrared spectroscopy results showed bands at wavenumbers of 556, 1499, 1704, 2342, 2358, 2973, 3433, and 3610 cm -1 that corresponded to the stretching and bending vibrations of Y-O, C=O and O-H. Thermoluminescence (TL) glow peaks for Y 2 O 3 :Tm 3+ nanophosphors observed at 399 and 590 K were attributed to oxygen defects caused using UV irradiation. These oxygen defects firstly resulted in an increased prominent peak TL intensity for up to 270 min of irradiation and then a decrease. This was attributed to the presence of oxygen defect clusters that caused a reduction in recombination centres. The Li + co-doped sample showed peaks at 356, 430, and 583 K and its intensity sublinearly increased up to 90 min and then thereafter decreased. The TL trapping parameters were calculated using computerized glow curve deconvolution methods. The Li + co-doped sample exhibited less fading and high trap density under the UV radiation., (© 2020 John Wiley & Sons, Ltd.)

The development of a highly effective photosensitizer (PS) that can be activated with a low-power single light is a pressing issue. Herein, we report a PS for synergistic photodynamic and photothermal therapy constructed through self-assembly of poly(selenoviologen) on the surface of core-shell NaYF 4 :Yb/Tm@NaYF 4 upconversion nanoparticles. The hybrid UCNPs/PSeV PS showed strong ROS generation ability and high photothermal conversion efficiency (∼52.5%) under the mildest reported-to-date irradiation conditions (λ = 980 nm, 150 mW/cm 2 , 4 min), leading to a high efficiency in killing methicillin-resistant Staphylococcus aureus (MRSA) both in vitro and in vivo . Remarkably, after intravenous injection, the reported PS accumulated preferentially in deep MRSA-infected tissues and achieved an excellent therapeutic index. This PS design realizes a low-power single-NIR light-triggered synergistic phototherapy and provides a simple and versatile strategy to develop safe clinically translatable agents for efficient treatment of deep tissue bacterial inflammations.

In spite of the rapid emergence of numerous nanoparticles (NPs) for biomedical applications, it is often challenging to precisely control, or effectively tame, the bioactivity/toxicity of NPs, thereby exhibiting limited applications in biomedical areas. Herein, we report the construction of hyaluronic acid (HA)-laminated, otherwise toxic methylviologen (MV), NPs via ternary host-guest complexation among cucurbit[8]uril, trans -azobenzene-conjugated HA, and MV-functionalized polylactic acid NPs (MV-NPs). The high, nonspecific toxicity of MV-NPs was effectively shielded (turned off) by HA lamination, as demonstrated in cells, zebrafish, and mouse models. The supramolecular host-guest interaction-mediated HA coating offered several HA-MV-NP modalities, including hyaluronidase locally and photoirradiation remotely, to precisely remove HA lamination on demand, thereby endowing materials with the capability of selective decoating-induced activation (DIA) for applications as a user-friendly herbicide, a selective antibacterial agent, or an anticancer nanomedicine. This work offers facile supramolecular coating and DIA strategies to effectively tame and precisely control the bioactivity and toxicity of functional nanomaterials for diverse applications.

Fluorescence sensing has the advantages of being real time, noninvasive, and convenient and having a low impact on the original environment for in vivo detection. Here, a reversible time-gated ratiometric in vivo detection method that could eliminate the interferences from probe amount, photon scattering, and absorption is proposed. Correspondingly, the composite probe must be able to reversibly respond to changes in the microenvironment and emit two luminescence signals at the same working wavelength but different lifetimes. Benefitting from the reversible detection mechanism, the probes could be used to monitor a dynamic biological process and the ratio signal value could be determined only by the concentration of analytes, independent of the probe concentration. Furthermore, benefitting from the same working wavelength, the read-out errors from photon absorption and scattering could be minimized. This method is very suitable for in vivo detection in which the probe distribution and depth are unknown and variable. As a typical model, different pH values in the gastrointestinal area and pH changes caused by drugs and fasting are successfully monitored.

As a newly emerging treatment strategy for many diseases, hydrogen therapy has attracted a lot of attention because of its excellent biosafety. However, the high diffusivity and low solubility of hydrogen make it difficult to accumulate in local lesions. Herein, we develop a H 2 self-generation nanoplatform by in situ water splitting driven by near-infrared (NIR) laser. In this work, core-shell nanoparticles (CSNPs) of NaGdF 4 :Yb,Tm/g-C 3 N 4 /Cu 3 P (UCC) nanocomposites as core encapsulated with zeolitic imidazolate framework-8 (ZIF-8) modified with folic acid as shell are designed and synthesized. Due to the acid-responsive ZIF-8 shell, enhanced permeability and retention (EPR) effect, and folate receptor-mediated endocytosis, CSNPs are selectively captured by tumor cells. Upon 980 nm laser irradiation, CSNPs exhibit a high production capacity of H 2 and active oxygen species (ROS), as well as an appropriate photothermal conversion temperature. Furthermore, rising temperature increases the Fenton reaction rate of Cu(I) with H 2 O 2 and strengthens the curative effect of chemodynamic therapy (CDT). The excess glutathione (GSH) in tumor microenvironment (TME) can deplete positive holes produced in the valence band of g-C 3 N 4 in the g-C 3 N 4 /Cu 3 P Z-scheme heterojunction. GSH also can reduce Cu(II) to Cu(I), ensuring a continuous Fenton reaction. Thus, a NIR-driven H 2 production nanoplatform is constructed for H 2 -mediated cascade-amplifying multimodal synergetic therapy.

Combining diagnostic and therapeutic functions in one agent is a promising strategy in the development of personalized approaches to the treatment of cancer. The opportunity to combine diagnostics and therapy appeared with the development of nanobiotechnologies and was realized in the concept of theranostics. To date, a number of promising agents based on nanomaterials capable of diagnosing, targeted therapeutic effects, and monitoring the response of tumor cells were obtained within the approach of theranostics. In this work, a new type of theranostic complexes based on upconversion nanoparticles coated with polyethylene glycol and functionalized with the DARPin-LoPE recombinant targeted toxin was developed. Selective binding of complexes to human breast adenocarcinoma cells overexpressing the HER2 receptor and specific toxicity to them were shown.

Ferrous ion (Fe 2+ ) is an important component of hemoglobin and plays a role in transporting O 2 to human tissues. If iron deficiency is present, iron deficiency anemia may occur, so it is critical to develop sensitive and accurate methods to detect Fe 2+ . Herein, a novel luminescence energy transfer (ET) system has been designed for the sensitive detection of Fe 2+ by a single-particle enumeration (SPE) method in the near-infrared (NIR) region through combining NIR-to-NIR β-NaGdF 4 :Yb,Tm@NaYF 4 upconversion nanoparticles (UCNPs) and IR-808 dye. IR-808 dye can quench the luminescence of the UCNPs because of the efficient overlap between the absorption spectrum of IR-808 and the emission spectrum of the UCNPs. When Fe 2+ and H 2 O 2 are added to the system, the Fenton reaction produces hydroxyl radicals (˙OH). The generated ˙OH reacts with IR-808 and the structure of IR-808 is destroyed. As a result, the ET process is suppressed, causing recovery of the luminescence of the UCNPs, which is reflected as an increase in the number of luminescent particles. Accurate quantification of Fe 2+ is achieved by statistically counting the target concentration-dependent luminescent particles. Under the optimal conditions, the linear detection range of Fe 2+ is 5-10 000 nM, which is much wider than the ensemble luminescence spectra measurements in bulk solution. Moreover, this strategy can be applied to detection in serum samples with satisfactory results.

This work reports a ZIF-8 (ZIF: Zeolitic Imidazolate Framework)-assisted NaYF 4 :Yb,Tm@ZnO upconverter for the photoelectrochemical (PEC) biosensing of carcinoembryonic antigen (CEA) under near-infrared (NIR) irradiation on a homemade 3D-printed device with DNA walker-based amplification strategy. The composite photosensitive material NaYF 4 :Yb,Tm@ZnO, as converter to transfer NIR import to photocurrent output, was driven from annealed NaYF 4 :Yb,Tm@ZIF-8. Yb 3+ and Tm 3+ -codoped NaYF 4 (NaYF 4 :Yb,Tm) converted NIR excitation into UV emission, matching with the absorption of ZnO for in situ excitation to generate the photocurrent. Upon target CEA introduction, the swing arm of DNA walker including the sequence of CEA aptamer carried out the sandwiched bioassembly with CEA capture aptamer on the G-rich anchorage DNA tracks-functionalized magnetic beads. Thereafter, DNA walker was triggered, and the swing arm DNA was captured by the G-rich anchorage DNA according to partly complementary pairing and Exonuclease III (Exo III) consumed anchorage DNA by a burnt-bridge mechanism to go into the next cycle. The released guanine (G) bases from DNA walker enhanced the photocurrent response on a miniature homemade 3D-printed device consisting of the detection cell, dark box, and light platform. Under optimal conditions, NaYF 4 :Yb,Tm@ZnO-based NIR light-driven PEC biosensor presented high sensitivity and selectivity for CEA sensing with a detection limit of 0.032 ng mL -1 . Importantly, our strategy provides a new horizon for the development of NIR-based PEC biosensors in the aspect of developing MOF-derived photoelectric materials, flexible design of a 3D-printed device, and effective signal amplification mode.

Rare-earth-based upconversion nanotechnology has recently shown great promise for photodynamic therapy (PDT). NaGd(MoO 4 ) 2 -based materials have a scheelite structure with good thermal and chemical stability, and excellent up-conversion luminescence properties after co-doping rare earth ions (Tm 3+ and Yb 3+ ), which can effectively excite the photosensitizer to generate reactive oxygen species (ROS). In this work, Tm 3+ and Yb 3+ co-doped NaGd(MoO 4 ) 2 upconversion nanoparticles (UCNPs) are prepared by the sol-gel method and further complexed with photosensitizer MC540 (UCNPs@MC540). The prepared UCNPs showed a tetragonal phase and revealed nanoparticles with an average size of 150 nm. Under 980 nm excitation, the UCNPs exhibited a dominant blue emission band ( 1 G 4 → 3 H 6 ) of Tm 3+ , while the optimum doping concentration was identified at 1% Tm 3+ and 20% Yb 3+ . In addition, the blue emissions of Tm 3+ simultaneously activate the MC540 composited on the surface of the nanoparticles to produce a large amount of singlet oxygen ( 1 O 2 ), which is detected by DCFH-DA. Moreover, UCNPs@MC540 also shows strong emission at around 800 nm near-infrared. The results show that the UCNPs@MC540 materials have potential application prospects in PDT and biological imaging.

Selective separation of heme proteins and peptides from complicated biological samples before comprehensive identification and characterization of intact biomolecules which are low stoichiometry is indispensable for ongoing proteomics. Here, three magnetic mesoporous rare-earth silicate (rare-earth = Er, Tm, Yb) microspheres prepared by facile solvothermal method were used as novel adsorbents for the selective isolation of bovine hemoglobin (BHb), and magnetic mesoporous ytterbium silicate showed apparent adsorption efficiency in isolating BHb with a adsorption capacity of 304.4 mg/g after the comparison. The retained BHb could be eluted by using Na 2 CO 3 as stripping reagent. Meanwhile, Circular dichroism spectra illustrated that the microspheres posed no effect on the secondary structure of BHb. The resultant magnetic particles were characterized by transmission electron microscope, scanning electron microscope, x-ray powder diffraction, vibrating sample magnetometer, Fourier transform infrared spectroscopy, N 2 adsorption-desorption isotherm and zeta potential. The as-prepared magnetic microspheres showed high specificity for the separation of BHb from bovine plasma as corroborated by SDS-PAGE and MALDI-TOF MS analysis, which would be expected to possess potential application in isolation of other heme proteins in complex biological samples., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The monitoring of alkaline phosphatase (ALP) activity in different tissues is significant for disease diagnosis and therapy. However, the time-resolved in vivo sensing of ALP activity remained unresolved. Herein, a novel red-near-infrared fluorescent ALP probe (Cl 2 -BDCM-ALP) based on a dichloro-substituted dicyanomethylene-4 H -chromene derivative was designed and synthesized with high fluorescence efficiency and stability under biological pH range. By using Cl 2 -BDCM-ALP, ALP activity under an acidic microenvironment such as a tumor site can be sensitively imaged, which cannot be achieved by some previously reported ALP probes. By further loading the Cl 2 -BDCM-ALP into a near-infrared (NIR) light-responsive nanocontainer, time-resolved long-term imaging of ALP activity was facilely achieved with noninvasive NIR light remote control. Time-resolved variation of ALP activity of the drug-induced acute liver injury mice was successfully monitored in vivo for the first time. This strategy holds great promise in the in situ ALP detection under a broad pH range with temporal resolution.

Under a 980-nm excitation, the up-conversion (UC) spectra of LuNbO 4 :Yb 3+ ,Tm 3+ powders exhibited predominantly near-infrared bands (~805 nm) of Tm 3+ through an energy transfer process from Yb 3+ to Tm 3+ . Regarding the down-conversion (DC) luminescence of the powders, the photoluminescence excitation spectra consisted of a broad charge transfer band (270 nm) due to [NbO 4 ] 3- and sharp band (360 nm) of Tm 3+ , while the corresponding emission spectra exhibited a blue emission at 458 nm. Upon substitution of Ga 3+ and Ta 5+ for Lu 3+ and Nb 5+ , respectively, both UC and DC luminescence properties were significantly enhanced. For the Ga 3+ substitution, the increased emission intensity could be explained by the crystal field asymmetry surrounding the Tm 3+ ions induced by the large difference in ionic radius between Ga 3+ and Lu 3+ . For the Ta 5+ substitution, we believe that an M'-LuTaO 4 substructure was formed in the host, which led to the formation of a TaO 6 octahedral coordination instead of a NbO 4 tetrahedral coordination. Consequently, the crystal symmetry of the local structure was modified, and thus the UC and DC luminescence properties were enhanced. The dual-mode (UC and DC) luminescence demonstrates that LuNbO 4 :Yb 3+ ,Tm 3+ has a great potential in the fields of temperature sensing probes, anti-counterfeiting, and bioapplications., (© 2019 John Wiley & Sons, Ltd.)

The development of optical thermometers operating within the first biological window (650-1000 nm) has drawn great interest lately in the biological and medical fields. Here a new type of luminescent thermometer relying on the intensity ratio between G 4 1-F 4 3 (652 nm) and F 2,3 3-H 6 3(691 nm) transitions in Tm 3+ /Yb 3+ :BaMoO 4 phosphor is reported under 980 nm excitation. The thermometry is found to be independent on the excitation power, benefiting the reduction of the measurement error. Moreover, it exhibits extremely high absolute sensitivity ranging from 210.5×10 -4 to 1034.5×10 -4   K -1 in 298-498 K. The maximal relative sensitivity and temperature resolutions (1.36%  K -1 and 0.37 K, respectively) are also among the highest values of those previous thermometric materials. This Letter provides guidance in selecting the suitable emission bands to construct the ratiometric luminescent thermometers with high performance.

In vivo fluorescence imaging in the second near-infrared window (NIR-II) affords deep-tissue penetration and high spatial resolution. Herein, we present a new type of Tm 3+ -sensitized lanthanide nanocrystals with both excitation (1208 nm) and emission (1525 nm) located in the NIR-II window for in vivo optical information storage and decoding. Taking advantage of the tunable fluorescence lifetimes, the optical multiplexed encoding capacity is enhanced accordingly. Micro-devices with QR codes featuring the NIR-II fluorescence-lifetime multiplexed encoding were implanted into mice and were successfully decoded through time-gated fluorescence imaging technology., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Photodynamic and immune therapies are innovative medical strategies against cancer, and their integration with upconversion nanoparticles (UCNPs) can improve the diagnosis and treatment of the disease. The UCNPs convert the deep penetrating near-infrared (NIR) light into higher energy emissions, allowing the imaging and detection of malignant cells and the simultaneous energy transfer for activation of the photosensitizers. In this work, the UCNPs were coated with a photocatalytic TiO 2 /ZrO 2 shell and an increase of oxygen defects (V O ) was observed as a result of the partial substitution of Ti 4+ by Zr 4+ ions in the crystalline lattice of TiO 2 . Such defects act as trapping states improving charge separation and then reducing the recombination rate of the electron-hole pairs (e - /h + ) generated upon resonant energy transfer from the donor (UCNPs) to acceptors (shell). The overall results are the enhancement of both ROS production and the emission band centered at 801 nm which is useful for tracking cells at the deep tissue level. However, an excess of those defects produces deleterious effects on both processes as a result of charge migration. The specificity against HER2 positive breast cancer was provided by bioconjugation with the monoclonal antibody trastuzumab. After administration of the synthesized NaYF 4 :Yb,Tm@TiO 2 /ZrO 2 -trastuzumab theranostic nanocomplex doped with an optimal ZrO 2 molar concentration (25%) and subsequent exposure to 975 nm light (0.71 W cm -2 ) during 5 minutes, HER2-positive SKBr3 breast cancer cells were suppressed with 88% drop of the cell viability, 28% higher than UCNPs decorated with a pure TiO 2 shell.

Upconversion nanoparticles (UCNPs) are new-generation photoluminescent nanomaterials gaining considerable recognition in the life sciences due to their unique optical properties that allow high-contrast imaging in cells and tissues. Upconversion nanoparticle applications in optical diagnosis, bioassays, therapeutics, photodynamic therapy, drug delivery, and light-controlled release of drugs are promising, demanding a comprehensive systematic study of their pharmacological properties. We report on production of biofunctional UCNP-based nanocomplexes suitable for optical microscopy and imaging of HER2-positive cells and tumors, as well as on the comprehensive evaluation of their pharmacokinetics, pharmacodynamics, and toxicological properties using cells and laboratory animals. The nanocomplexes represent a UCNP core/shell structure of the NaYF4:Yb, Er, Tm/NaYF4 composition coated with an amphiphilic alternating copolymer of maleic anhydride with 1-octadecene (PMAO) and conjugated to the Designed Ankyrin Repeat Protein (DARPin 9_29) with high affinity to the HER2 receptor. We demonstrated the specific binding of UCNP-PMAO-DARPin to HER2-positive cancer cells in cultures and xenograft animal models allowing the tumor visualization for at least 24 h. An exhaustive study of the general and specific toxicity of UCNP-PMAO-DARPin including the evaluation of their allergenic, immunotoxic, and reprotoxic properties was carried out. The obtained experimental body of evidence leads to a conclusion that UCNP-PMAO and UCNP-PMAO-DARPin are functional, noncytotoxic, biocompatible, and safe for imaging applications in cells, small animals, and prospective clinical applications of image-guided surgery., (© The Author(s) 2019. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

For a number of years nanomaterials have been continuously devised and comprehensively investigated because of the growing demand for them and their multifarious applications, especially in medicine. This paper reports on the properties of SrF 2 nanoparticles (NPs) for applications in biomedicine, showing effective ways of their synthesis and luminescence under near infrared radiation - upconversion. NPs doped with lanthanide, Ln 3+ ions (where Ln = Yb, Ho, Er, Tm) were prepared by the hydrothermal method and subjected to comprehensive studies, from determination of their structure and morphology, revealing small, 15 nm structures, through spectroscopic properties, to cytotoxicity in vitro. The effects of such factors as the reaction time, type and amount of precipitating compounds and complexing agents on the properties of products were characterized. The cytotoxicity of the synthesized and functionalized NPs was investigated, using human fibroblast cell line (MSU-1.1). The synthesized structures may decrease cells' proliferation in a dose-dependent manner in the measured concentration range (up to 100 µg/mL). However, the cells remain alive according to the fluorescent assay. Moreover, the treated cells were imaged using confocal laser scanning microscopy. Cellular uptake was confirmed by the presence of upconversion luminescence in the cells.

Raman spectra of aqueous Ho 3+ , Er 3+ , Tm 3+ , Yb 3+ , and Lu 3+ -perchlorate solutions were measured over a large wavenumber range from 50-4180 cm -1 . In the low wavenumber range (terahertz region), strongly polarized Raman bands were detected at 387 cm -1 , 389 cm -1 , 391 cm -1 , 394 cm -1 , and 396 cm -1 , respectively, which are fairly broad (full widths at half height at ~52 cm -1 ). These isotropic Raman bands were assigned to the breathing modes, ν 1 Ln-O of the heavy rare earth (HRE) octaaqua ions, [Ln(H 2 O) 8 ] 3+ . The strong polarization of these bands (depolarization degree ~0) reveals their totally symmetric character. The vibrational isotope effect was measured in Yb(ClO 4 ) 3 solutions in H 2 O and D 2 O and the shift of the ν 1 mode in changing from H 2 O to D 2 O further supports the character of the band. The Ln-O bond distances of these HRE ions (Ho 3+ , Er 3+ , Tm 3+ , Yb 3+ , and Lu 3+ ) follow the order of Ho-O > Er-O > Tm-O > Yb-O > Lu-O which correlates inversely with the band positions of the breathing modes of their corresponding octaaqua ions [Ln(OH 2 ) 8 ] 3+ . Furthermore, the force constants, k Ln-O , were calculated for these symmetric stretching modes. Ytterbium perchlorate solutions were measured over a broad concentration range, from 0.240 mol·L -1 to 2.423 mol·L -1 , and it was shown that with increasing solute concentration outer-sphere ion pairs and contact ion pairs were formed. At the dilute solution state (~0.3 mol·L -1 ), the fully hydrated ions [Yb(H 2 O) 8 ] 3+ exist, while at higher concentrations (C T > 2 mol·L -1 ), ion pairs are formed. The concentration behavior of Yb(ClO 4 ) 3 (aq) shows similar behavior to the one observed for La(ClO 4 ) 3 (aq), Ce(ClO 4 ) 3 (aq) and Lu(ClO 4 ) 3 (aq) solutions. In ytterbium chloride solutions in water and heavy water, representative for the behavior of the other HRE ions, 1:1 chloro-complex formation was detected over the concentration range from 0.422-3.224 mol·L -1 . The 1:1 chloro-complex in YbCl 3 (aq) is very weak, diminishing rapidly with dilution and vanishing at a concentration < 0.4 mol·L -1 .

Objective: This article describes the preparation of a 170 Tm source by chemical deposition technique, its encapsulation in a titanium holder, and preliminary quality evaluation for potential utility as a brachytherapy source., Methods: The procedure consisted of electrodeposition of Ni on a Cu wire followed by chemical deposition of 170 Tm on it. Influence of feed solution pH, carrier Tm concentration, and reaction time were studied for optimum deposition of 170 Tm on substrate. After sealing the source core in a titanium capsule, quality control tests were performed. Distribution of 170 Tm on substrate was evaluated by autoradiography. Inactive Tm source was characterized by scanning electron microscope (SEM) and energy-dispersive X-ray (EDS) analyses., Results: Under optimized conditions (pH 5, 10 μg Tm carrier, 5 h), 170 Tm source core could be prepared by deposition of >95% of 170 Tm radioactivity on substrate. Swipe tests and immersion tests on encapsulated sources confirmed that removable radioactivity and radioactivity leakage levels were within stipulated limits. Autoradiography of 170 Tm source confirmed uniformity of radioactivity distribution. While SEM analysis confirmed good adhesion of Tm on substrate, EDS analysis confirmed elemental constituents of the Tm-deposited substrate., Conclusion: The objective of preparing a 170 Tm source by chemical deposition for potential brachytherapy applications could be successfully achieved.

Lanthanide-doped upconverting nanoparticles (UCNP) are being extensively studied for bioapplications due to their unique photoluminescence properties and low toxicity. Interest in RET applications involving UCNP is also increasing, but due to factors such as large sizes, ion emission distributions within the particles, and complicated energy transfer processes within the UCNP, there are still many questions to be answered. In this study, four types of core and core-shell NaYF₄-based UCNP co-doped with Yb 3+ and Tm 3+ as sensitizer and activator, respectively, were investigated as donors for the Methyl 5-(8-decanoylbenzo[1,2-d:4,5-d']bis([1,3]dioxole)-4-yl)-5-oxopentanoate (DBD-6) dye. The possibility of resonance energy transfer (RET) between UCNP and the DBD-6 attached to their surface was demonstrated based on the comparison of luminescence intensities, band ratios, and decay kinetics. The architecture of UCNP influenced both the luminescence properties and the energy transfer to the dye: UCNP with an inert shell were the brightest, but their RET efficiency was the lowest (17%). Nanoparticles with Tm 3+ only in the shell have revealed the highest RET efficiencies (up to 51%) despite the compromised luminescence due to surface quenching.

Spatial and temporal distributions of metal ions in vitro and in vivo are crucial in our understanding of the roles of metal ions in biological systems, and yet there is a very limited number of methods to probe metal ions with high space and time resolution, especially in vivo. To overcome this limitation, we report a Zn 2+ -specific near-infrared (NIR) DNAzyme nanoprobe for real-time metal ion tracking with spatiotemporal control in early embryos and larvae of zebrafish. By conjugating photocaged DNAzymes onto lanthanide-doped upconversion nanoparticles (UCNPs), we have achieved upconversion of a deep tissue penetrating NIR 980 nm light into 365 nm emission. The UV photon then efficiently photodecages a substrate strand containing a nitrobenzyl group at the 2'-OH of adenosine ribonucleotide, allowing enzymatic cleavage by a complementary DNA strand containing a Zn 2+ -selective DNAzyme. The product containing a visible FAM fluorophore that is initially quenched by BHQ1 and Dabcyl quenchers is released after cleavage, resulting in higher fluorescent signals. The DNAzyme-UCNP probe enables Zn 2+ sensing by exciting in the NIR biological imaging window in both living cells and zebrafish embryos and detecting in the visible region. In this study, we introduce a platform that can be used to understand the Zn 2+ distribution with spatiotemporal control, thereby giving insights into the dynamical Zn 2+ ion distribution in intracellular and in vivo models.

A nanoengineered interface fabricated by self-assembly enables the online determination of vitamin B12 via a simple luminescence readout in serum without any pretreatment. The interplay of Tm 3+ -doped NaYF 4 nanoparticles (UCNPs) and a gold nanotriangle array prepared by nanosphere lithography on a glass slide is responsible for an efficient NIR to UV upconversion. Hot spots of the gold assembly generate local electromagnetic-field enhancement, favoring the four-photon upconversion process at the low-power excitation of approximately 13 W·cm -2 . An improvement by about 6 times of the intensity for the emission peaking at 345 nm is achieved. The nanoengineered interface has been applied in a proof-of-concept sensor for vitamin B12 in serum, which is known as a marker for the risk of cancer; Alzheimer disease; or, during pregnancy, neurological abnormalities in newborn babies. Vitamin B12 can be detected in serum down to 3.0 nmol·L -1 by a simple intensity-based optical readout, consuming only 200 μL of a sample, which qualifies as easy miniaturization for point-of-care diagnostics. Additionally, this label-free approach can be used for long-term monitoring because of the high photostability of the upconversion nanoparticles.

The fluorescence and physical properties of thulium-doped zirconia were investigated. A standard grade of zirconia (TZ-3Y-E) and two translucent dental zirconia materials (Zpex and Zpex Smile) were examined. The specimens were prepared by addition of 0-1.5 wt% Tm 2 O 3 and then sintering. When exposed to UV light, the Tm 2 O 3 -doped zirconia exhibited blue fluorescence with a peak wavelength of 460 nm. The fluorescence intensity of Zpex and Zpex Smile was higher than that of TZ-3Y-E, with Zpex being more intense than Zpex Smile. Zpex exhibited maximum fluorescence intensity when doped with 0.8 wt% Tm 2 O 3 . XRD analysis revealed that TZ-3Y-E and Zpex contained primarily tetragonal zirconia, while Zpex Smile contained largely cubic phase zirconia. There were no changes observed in the microstructure or physical properties of the zirconia specimens when doped with Tm 2 O 3 .

In this work, we explore a photochemical ligation reaction to covalently modify oligonucleotide-conjugated upconverting nanoparticles (UCNPs) in the presence of a specific target DNA sequence. The target sequence acts as a hybridization template, bringing together a biotinylated photoactivatable oligonucleotide probe and the oligonucleotide probe that is attached to UCNPs. The illumination of the UCNPs by NIR light to generate UV emission internally or illuminating the photoactivatable probe directly by an external UV light promotes the photochemical ligation reaction, yielding covalently biotin functionalized UCNPs that can be selectively captured in streptavidin-coated microwells. Following this strategy, we developed a DNA sensor with a limit of detection of 1 × 10 -18 mol per well (20 fM). In addition, we demonstrate the possibility to create UCNP patterns on the surface of solid supports upon NIR illumination that are selectively formed under the presence of the target oligonucleotide.

In this work, a Tm 3+ -doped solgel silica microsphere lasing at 2.0 μm is reported. Microspheres with different Tm 3+ concentrations are fabricated by overlaying different Tm 3+ concentration solgel solutions on the surface of a pure silica microsphere resonator and then annealing the sample with a CO 2 laser. Based on a traditional fiber taper-microsphere coupling method, single and multimode microsphere lasing in the wavelength range 1.8-2.0 μm is observed if an 808 nm laser diode is used as a pump source. A relatively low threshold pumping power of 1.2 mW is achieved using this arrangement. This solgel method allows for an easy varying of the Tm 3+ doping concentration. The observed laser output shifts to longer wavelengths when the Tm 3+ doping concentration increases. This has been explained by the larger Tm absorption at shorter wavelengths. The ability to fabricate solgel co-doped silica glass microlasers represents a new generation of low threshold and compact infrared laser sources for use as miniaturized photonic components for a wide range of applications, including gas sensing and medical surgery.

Photodynamic therapy (PDT) involves the combination of non-toxic dyes called photosensitizers (PS) and harmless visible light that interact with ambient oxygen to give reactive oxygen species (ROS) that can damage biomolecules and kill cells. PDT has mostly been developed as a cancer therapy but can also be used as an antimicrobial approach against localized infections. However even the longest wavelength used for exciting PS (in the 700 nm region) has relatively poor tissue penetration, and many PS are much better excited by blue and green light. Therefore upconversion nanoparticles (UCNPs) have been investigated in order to allow deeper-penetrating near-infrared light (980 nm or 810 nm) to be used for PDT. NaYF 4 nanoparticles doped with Yb 3+ and Er 3+ or with Tm 3+ and Er 3+ have been attached to PS either by covalent conjugation, or by absorption to the coating or shell (used to render the UCNPs biocompatible). Forster resonance energy transfer to the PS then allows NIR light energy to be transduced into ROS leading to cell killing and tumor regression. Some studies have experimentally demonstrated the deep tissue advantage of UCNP-PDT. Recent advances have included dye-sensitized UCNPs and UCNPs coupled to PS, and other potentially synergistic drug molecules or techniques. A variety of bioimaging modalities have also been combined with upconversion PDT. Further studies are necessary to optimize the drug-delivery abilities of the UCNPs, improve the quantum yields, allow intravenous injection and tumor targeting, and ensure lack of toxicity at the required doses before potential clinical applications.

Photodynamic therapy (PDT) is a noninvasive therapeutic technique. Upconversion nanoparticles (UCNPs) hold promise for photodynamic therapy (PDT). UCNPs with antistokes emission can improve the tissue penetration depth of PDT. However, the low upconversion efficiency poses a strong limit on further development of PDT. The core/shell structure Yb/Tm/GZO@SiO 2 UCNPs are designed, which can form multistep cascade energy transfer from sillica shell to core Ga-doped Yb/Tm/ZnO. Compared with Yb/Tm/ZnO upconversion (UC) semiconductor nanoparticles (SNCs), the multistep cascade energy transfer process provides about seven times enhanced UCL emission. For the UCL-optimized core/shell upconversion SNCs of Yb 7 /Tm 0.5 /G 3 ZO@mSiO 2 , the Yb 3+ energy transfer efficiency is determined to be as high as ∼81% under 980 nm laser excitation. In addition, the Yb 7 /Tm 0.5 /G 3 ZO@mSiO 2 core/shell UCNPs have an excellent PDT treatment for Hela cells under 980 nm laser excitation.