Dual-Responsive and ROS-Augmented Nanoplatform for Chemo/Photodynamic/Chemodynamic Combination Therapy of Triple Negative Breast Cancer.

Integrating chemodynamic therapy (CDT) and photodynamic therapy (PDT) into one nanoplatform can produce much more reactive oxygen species (ROS) for tumor therapy. Nevertheless, it is still a great challenge to selectively generate sufficient ROS in tumor regions. Meanwhile, CDT and PDT are restricted by insufficient H2O2 content in the tumor as well as by the limited tumor tissue penetration of the light source. In this study, a smart pH/ROS-responsive nanoplatform, Fe2+@UCM-BBD, is rationally designed for tumor combination therapy. The acidic microenvironment can induce the pH-responsive release of doxorubicin (DOX), which can induce tumor apoptosis through DNA damage. Beyond that, DOX can promote the production of H2O2, providing sufficient materials for CDT. Of note, upconversion nanoparticles at the core can convert the 980 nm light to red and green light, which are used to activate Ce6 to produce singlet oxygen (1O2) and achieve upconversion luminescence imaging, respectively. Then, the ROS-responsive linker bis-(alkylthio)alkene is cleaved by 1O2, resulting in the release of Fenton reagent (Fe2+) to realize CDT. Taken together, Fe2+@UCM-BBD exhibits on-demand therapeutic reagent release capability, excellent biocompatibility, and remarkable tumor inhibition ability via synergistic chemo/photodynamic/chemodynamic combination therapy.

A Janus upconverting nanoplatform with biodegradability for glutathione depletion, near-infrared light induced photodynamic therapy and accelerated excretion.

The major limitations of photodynamic therapy (PDT) are the poor tissue penetration of excitation light and the neutralization of reactive oxygen species (ROS) generated by overexpressed glutathione (GSH) in cancer cells. Despite tremendous efforts to design nanoplatforms, PDT still suffers from unsatisfactory effects. Furthermore, the residual of nanomaterials in the body has restricted their clinical application. To address these issues, Janus nanocomposites containing an Yb/Er codoped NaYF4 upconverting nanocrystal head and a disulfide-bridged mesoporous organosilicon body (UCN/MON) with loaded chlorin e6 (Ce6) were designed. On one hand, the upconverting nanocrystal head can convert near-infrared (NIR) light into visible light to activate Ce6 to release ROS. On the other hand, the silica body can be degraded though a redox reaction with GSH, to not only improve the tumor selectivity of the photosensitizer by redox- and pH-triggered Ce6 release, but also diminish the concentration of GSH in cancer cells to reduce the depletion of ROS. Thereby, an enhanced PDT triggered by NIR irradiation was achieved. Furthermore, UCN/MONs showed a higher clearance rate after therapeutic actions than nonbiodegradable UCN/MSNs due to their biocompatibility. Taken together, this work revealed the potential of UCN/MONs for highly efficient and NIR-induced PDT, highlighting the prospects of UCN/MONs in the clinic.

Aptamer-modified sensitive nanobiosensors for the specific detection of antibiotics.

The overuse or abuse of quinolone antibiotics such as enrofloxacin (ENR) in veterinary medicine results in the presence of their residues in food and environment. Thus, a sensitive method is needed to detect them. Herein, we demonstrate a fluorescence resonance energy transfer (FRET) based aptasensor for ENR detection, using core-shell upconversion nanoparticles (CSUNPs) as an energy donor and graphene oxide (GO) as an energy acceptor. The core-shell structure and Gd3+ doping significantly increased the fluorescence intensity of CSUNPs and the FRET efficiency. The ENR aptamer was conjugated to CSUNPs through ligand exchange, and the π-π stacking between the aptamer and GO brought the aptamer-modified CSUNPs to the surface of the GO sheets, resulting in the formation of a CSUNP-GO complex and the subsequent quenching of CSUNP fluorescence. As a result, an aptasensor was established with the fluorescence of CSUNPs correlated with the ENR concentration within the range of 0.976 ng mL-1 to 62.5 ng mL-1, allowing ENR to be detected at a limit of 0.47 ng mL-1. This method reduced the detection limit by approximately 13-fold in 2 h compared to the commercial enzyme-linked immunosorbent assay (ELISA) kit. The aptasensor could also be applied to detect ENR from commercial milk powder samples with a detection limit of 1.59 ng mL-1, which was far below the regulated maximum residue limit of ENR in milk. The aptasensor could not detect other antibiotics, suggesting its good specificity towards ENR. Our work demonstrates a highly selective, sensitive and cost-effective method for detecting antibiotic residues in veterinary medicine. Since the aptamer can be switched to one recognizing another antibiotic, the aptasensors are used as a plug-and-play platform that can detect a variety of antibiotics.

Highly Doped Upconversion Nanoparticles for In Vivo Applications Under Mild Excitation Power.

One of the major challenges in using upconversion nanoparticles (UCNPs) is to improve their brightness. This is particularly true for in vivo studies, as the low power excitation is required to prevent the potential photo toxicity to live cells and tissues. Here, we report that the typical NaYF4:Yb0.2,Er0.02 nanoparticles can be highly doped, and the formula of NaYF4:Yb0.8,Er0.06 can gain orders of magnitude more brightness, which is applicable to a range of mild 980 nm excitation power densities, from 0.005 W/cm2 to 0.5 W/cm2. Our results reveal that the concentration of Yb3+ sensitizer ions plays an essential role, while increasing the doping concentration of Er3+ activator ions to 6 mol % only has incremental effect. We further demonstrated a type of bright UCNPs 12 nm in total diameter for in vivo tumor imaging at a power density as low as 0.0027 W/cm2, bringing down the excitation power requirement by 42 times. This work redefines the doping concentrations to fight for the issue of concentration quenching, so that ultrasmall and bright nanoparticles can be used to further improve the performance of upconversion nanotechnology in photodynamic therapy, light-triggered drug release, optogenetics, and night vision enhancement.

Upconversion luminescence-infrared absorption nanoprobes for the detection of prostate-specific antigen.

Aiming to the ongoing challenge of accurate and sensitive detection for cancer biomarkers, antibody-functionalized NaYF4:Yb3+, Er3+@SiO2 nanorods were developed as upconversion luminescence (UCL)-infrared absorption (IRA) nanoprobes. Benefiting from the shielding effect of the SiO2 shell, an enhanced UCL was achieved. Additionally, an IRA detection signal was introduced by the Si-O-Si bonds of SiO2. Its mutual verification with UCL signal was favorable for ensuring the accuracy of the assay. A UCL-IRA sandwich detection method was established for the detection of the prostate-specific antigen. The UCL intensity at 542 nm and IRA at 1095 cm-1 were chosen for quantitative assay. The method has high sensitivity (0.05 pg mL-1) and selectivity. The range of detection (200 fg mL-1-200 ng mL-1) was singnificantly broadened compared with that of single-readout UCL or IRA detection. The assay performance of human serum samples demonstrated the practicability of the method in clinical cancer diagnosis. Graphical abstract.

Lateral flow immunostrips for the sensitive and rapid determination of 8-hydroxy-2'-deoxyguanosine using upconversion nanoparticles.

Lateral flow immunostrips were newly designed and a sensitive and rapid fluorometric method for the determination of 8-hydroxy-2'-deoxyguanosine (8-OHdG) as a model target of small biomarker molecules was developed. The upconversion nanoparticles (UCNPs, NaYF4:Yb/Er core, and polyacrylic acid (PAA)-modified shell, size ~ 39 nm, excitation wavelength = 980 nm; emission wavelength = 540 nm) were employed as fluorescence signal material. The 8-OHdG antibody (Ab) was taken as the recognition probe while UCNP-labeled Ab was taken as the signal probe. Bovine serum albumin (BSA) was designed as carrier protein for 8-OHdG to form 8-OHdG-BSA conjugate as the capture probe. The lateral flow immunostrips were prepared by laminating a sample pad (glass fiber membrane), a test pad (nitrocellulose membrane), and adsorption pad (filter paper) on PVP backing. The capture probe was immobilized on the test zone while an IgG antibody taken as the control probe was immobilized on the control zone. When the signal probe and the sample were in sequence loaded on the sample pad, 8-OHdG analyte bound with the signal probe, and then the excess of the signal probe move along the strip and is collected by the capture probe on the test zone while the remnant signal probe is collected by the control probe on the control zone. The signal probe and capture probe were synthesized and characterized. The fluorescence intensity on the test zone was inversely proportional to the concentration of 8-OHdG for the quantitative determination while the fluorescence emission on the control zone was observed to validate the assay. The developed method showed a wide linear range from 0.10 to 10 nM, a quite low detection limit of 0.05 nM, small sample volume requirement (100 µL), short assay time (15 min), and good method reproducibility (RSD = 4.4%, nine immunostrips). Graphical abstract Schematic illustration of the configuration and measurement principle of lateral flow fluorescence immunostrip for 8-OHdG: (a) configuration; (b) preparation: load of capture probe (BSA-8-OHdG, 2 µL) on test zone; load of control probe (IgG Ab, 2 µL) on control zone; load of signal probe (UCNP-Ab, 16 µL) on sample pad; (c) measurement: load of sample (8-OHdG, 100 µL) on sample pad, collection, and measurement.

NaGdF4:Yb,Er-Ag nanowire hybrid nanocomposite for multifunctional upconversion emission, optical imaging, MRI and CT imaging applications.

The effect of novel silver nanowire encapsulated NaGdF4:Yb,Er hybrid nanocomposite on the upconversion emission and bioimaging properties has been investigated. The upconvension nanomaterials were synthesised by polyol method in the presence of ethylene glycol, PVP and ethylenediamine. The NaGdF4:Yb,Er-Ag hybrid was formed with upconverting NaGdF4:Yb,Er nanoparticles of size ~ 80 nm and silver nanowires of thickness ~ 30 nm. The surface plasmon induced by the silver ion in the NaGdF4:Yb,Er-Ag nanocomposite resulted an intense upconversion green emission at 520 nm and red emission at 660 nm by NIR diode laser excitation at 980 nm wavelength. The UV-Vis-NIR spectral absorption at 440 nm and 980 nm, the intense Raman vibrational modes and the strong upconversion emission results altogether confirm the localised surface plasmon resonance effect of silver ion in the hybrid nanocomposite. MRI study of both NaGdF4:Yb,Er nanoparticle and NaGdF4:Yb,Er-Ag nanocomposite revealed the T1 relaxivities of 22.13 and 10.39 mM-1 s-1, which are larger than the commercial Gd-DOTA contrast agent of 3.08 mM-1 s-1. CT imaging NaGdF4:Yb,Er-Ag and NaGdF4:Yb,Er respectively showed the values of 53.29 HU L/g and 39.51 HU L/g, which are higher than 25.78 HU L/g of the CT contrast agent Iobitridol. The NaGdF4:Yb,Er and NaGdF4:Yb,Er-Ag respectively demonstrated a negative zeta potential of 54 mV and 55 mV, that could be useful for biological application. The in vitro cytotoxicity of the NaGdF4:Yb,Er tested in HeLa and MCF-7 cancer cell line by MTT assay demonstrated a cell viability of 90 and 80 %, respectively. But, the cell viability of NaGdF4:Yb,Er-Ag slightly decreased to 80 and 78%. The confocal microscopy imaging showed that the UCNPs are effectively up-taken inside the nucleolus of the cancer cells, and it might be useful for NIR laser-assisted phototherapy for cancer treatment. Graphical abstract.

A paper-supported sandwich immunosensor based on upconversion luminescence resonance energy transfer for the visual and quantitative determination of a cancer biomarker in human serum.

In this paper, a paper-supported analytical device based on a sandwich immunoreaction and luminescence resonance energy transfer (LRET) was reported for the visual and quantitative determination of a cancer biomarker, in which upconversion nanoparticles (UCNPs) were located on the surface of the paper as energy donors and gold nanoparticles (AuNPs) were used as energy acceptors. Upon the recognition of the cancer biomarker by two rationally selected antibodies, the upconversion luminescence was quenched by the AuNPs in a biomarker concentration-dependent manner. As a model target, CEA was detected using this immunosensor, and a linear relationship within 0.5-30 ng mL-1 was obtained in buffer solution, with a detection limit of 0.21 ng mL-1. The immunosensor was also applicable in 20-fold diluted human serum with a linear range of 0.5-30 ng mL-1 and a detection limit of 0.36 ng mL-1. This technique also realized the qualitative judgment of the critical concentration of CEA in serum samples by the naked eye. This approach displays great application potential for point-of-care testing in clinical applications, as well as the potentiality to be extended to other kinds of disease-related biomolecules.

Self-Sufficient and Highly Efficient Gold Sandwich Upconversion Nanocomposite Lasers for Stretchable and Bio-applications.

Multifunctional lanthanide-doped upconversion nanoparticles (UCNPs) have spread their wings in the fields of flexible optoelectronics and biomedical applications. One of the ongoing challenges lies in achieving UCNP-based nanocomposites, which enable a continuous-wave (CW) laser action at ultralow thresholds. Here, gold sandwich UCNP nanocomposites [gold (Au1)-UCNP-gold (Au2)] capable of exhibiting lasing at ultralow thresholds under CW excitation are demonstrated. The metastable energy-level characteristics of lanthanides are advantageous for creating population inversion. In particular, localized surface plasmon resonance-based electromagnetic hotspots in the nanocomposites and the huge enhancement of scattering coefficient for the formation of coherent closed loops due to multiple scattering facilitate the process of stimulated emissions as confirmed by theoretical simulations. The nanocomposites are subjected to stretchable systems for enhancing the lasing action (threshold ∼ 0.06 kW cm-2) via a light-trapping effect. The applications in bioimaging of HeLa cells and antibacterial activity (photothermal therapy) are demonstrated using the newly designed Au1-UCNP-Au2 nanocomposites.

Dispersion stability and biocompatibility of four ligand-exchanged NaYF4: Yb, Er upconversion nanoparticles.

Surface modification to obtain high dispersion stability and biocompatibility is a key factor for bio-application of upconversion nanoparticles (UCNPs). A systematic study of UCNPs modified with four hydrophilic molecules separately, comparing their dispersion stability in biological buffers and cellular biocompatibility is reported here. The results show that carboxyl-functionalized UCNPs (modified by 3,4-dihydrocinnamic acid (DHCA) or poly(monoacryloxyethyl phosphate (MAEP)) with negative surface charge have superior even-distribution in biological buffers compared to amino-functionalized UCNPs (modified by (aminomethyl)phosphonic (AMPA) or (3-Aminopropyl)triethoxysilane (APTES)) with positive surface charge. Subsequent investigation of cellular interactions revealed high levels of non-targeted cellular uptake of the particles modified with either of the three small molecules (AMPA, APTES, DHCA) and high levels of cytotoxicity when used at high concentrations. The particles were seen to be trapped as particle-aggregates within the cellular cytoplasm, leading to reduced cell viability and cell proliferation, along with dysregulation of the cell cycle as assessed by DNA content measurements. The dramatically reduced proportion of cells in G1 phase and the slightly increased proportion in G2 phase indicates inhibition of M phase, and the appearance of sub-G1 phase reflects cell necrosis. In contrast, MAEP-modified UCNPs are bio-friendly with increased dispersion stability in biological buffers, are non-cytotoxic, with negligible levels of non-specific cellular uptake and no effect on the cell cycle at both low and high concentrations. MAEP-modified UCNPs were further functionalized with streptavidin for intracellular microtubule imaging, and showed clear cytoskeletal structures via their upconversion luminescence. STATEMENT OF SIGNIFICANCE: Upconversion nanoparticles (UCNP) are an exciting potential nanomaterial for bio-applications. Their anti-Stokes luminescence makes them especially attractive to be used as imaging probes and thermal therapeutic reagents. Surface modification is the key to achieving stable and compatible hydrophilic-UCNPs. However, the lack of criteria to assess molecular ligands used for ligand exchange of nanoparticles has hampered the development of surface modification, and further limits UCNP's bio-application. Herein, we report a systematic comparative study of modified-UCNPs with four distinct hydrophilic molecules, assessing each particles' colloidal stability in biological buffers and their cellular biocompatibility. The protocol established here can serve as a potential guide for the surface modification of UCNPs in bio-applications.

A Turn-On Luminescence Method for Phosphate Determination Based on Fast Green-Functionalized ZrO2:Yb,Er@ZrO2 Core@Shell Upconversion Nanoparticles.

The development of practical and sensitive tools for detecting phosphate deficiency could facilitate engineering approaches to enhance crop yield and quality in phosphate-stressed environments, reducing the misuse of nonrenewable fertilizers and their consequent ecological impact. Herein, a 975 nm-activated method based on ZrO2:Yb,Er@ZrO2 core@shell upconversion nanoparticles is presented for rapid visualization and determination of the phosphate ions in aqueous solutions and extracts. At optimized thickness, the nondoped ZrO2 shell not only enhances the emission of the ZrO2:Yb,Er but also provides an active surface for the intense interaction with the phosphate group, allowing a "label-free" determination that avoids the use of additional phosphate-recognizing elements like ligands or antibodies. According to the experimental evidence, the optical output of the ZrO2:Yb,Er@ZrO2 nanoparticles specifically matches with the absorption spectrum of the fast green alimentary dye (FG) electrostatically attached to the nanoparticle surface, activating the Förster resonance energy transfer (FRET) and thereby the upconversion luminescence quenching. Upon addition of the phosphate ions and the covalent interaction with the ZrO2:Yb,Er@ZrO2-FG nanocomplex, the FG is gradually removed, displaying a fast and reproducible "turn-on" luminescence which allows measurements in a few minutes. This rapid response is due to the stronger coordination between the ZrO2 shell and the phosphate compared to the FG molecules (-31.97 and -5.99 eV, respectively). The detection method was then effectively modulated in a 20-1000 nM linear response range without interfering effects of commonly coexisting ions, achieving a detection limit up to 15 times lower than that obtained with the conventionally used colorimetric methods.

Linker-protein G mediated functionalization of polystyrene-encapsulated upconversion nanoparticles for rapid gene assay using convective PCR.

The authors report on a simplified approach to encapsulate upconversion nanoparticles (UCNPs) in polystyrene spheres by mini-emulsion polymerisation. The resulting particles (PS-UCNP) are hydrophilic, stable and suitable for biomolecular recognition and biosensing applications. Also, a strategy was developed for bioconjugation of antibodies onto the surface of the PS-UCNPs by using the bifunctional fusion protein linker-protein G (LPG). LPG mediates the functionalisation of PS-UCNPs with antibodies against digoxigenin allowing for specific labelling of convective PCR (cPCR) amplicons. Lambda DNA was amplified using cPCR on a heat block for 30 min using the digoxigenin labelled forward and biotin labelled reverse primers. The antibody functionalised PS-UCNPs bind to the digoxigenin end of the cPCR amplicons. Finally, the streptavidin labelled magnetic beads were used to selectively capture the PS-UCNP-labelled cPCR amplicons and the upconversion signal was detected at 537 nm under 980 nm excitation. This sandwich approach enables direct recognition of the target lambda DNA with a detection limit of 103 copies µL-1. The upconversion signal decreased proportionally to the concentration of the lambda DNA with a linear response between 107 and 103 copies of DNA. Graphical abstract Schematic representation of polystyrene-encapsulated upconversion nanoparticles (PS-UCNPs) prepared by mini-emulsion polymerisation. The PS-UCNPs were functionalised with anti-digoxigenin antibody using the fusion protein linker-protein G (LPG). Detection of digoxigenin-labelled amplicons is achieved (a) by using the antibody-functionalised LPG@PS-UCNP labels; (b) magnetic separation, and (c) 980 nm laser light for detection of the green upconversion luminescence peaking at 537 nm.

Optically Monitoring Mineralization and Demineralization on Photoluminescent Bioactive Nanofibers.

Bone regeneration and scaffold degradation do not usually follow the same rate, representing a daunting challenge in bone repair. Toward this end, we propose to use an external field such as light (in particular, a tissue-penetrating near-infrared light) to precisely monitor the degradation of the mineralized scaffold (demineralization) and the formation of apatite mineral (mineralization). Herein, CaTiO3:Yb(3+),Er(3+)@bioactive glass (CaTiO3:Yb(3+),Er(3+)@BG) nanofibers with upconversion (UC) photoluminescence (PL) were synthesized. Such nanofibers are biocompatible and can emit green and red light under 980 nm excitation. The UC PL intensity is quenched during the bone-like apatite formation on the surface of the nanofibers in simulated body fluid; more mineral formation on the nanofibers induces more rapid optical quenching of the UC PL. Furthermore, the quenched UC PL can recover back to its original magnitude when the apatite on the nanofibers is degraded. Our work suggests that it is possible to optically monitor the apatite mineralization and demineralization on the surface of nanofibers used in bone repair.

The thermoluminescence glow curve and the deconvoluted glow peak characteristics of erbium doped silica fiber exposed to 70-130 kVp x-rays.

In regard to thermoluminescence (TL) applied to dosimetry, in recent times a number of researchers have explored the role of optical fibers for radiation detection and measurement. Many of the studies have focused on the specific dopant concentration, the type of dopant and the fiber core diameter, all key dependencies in producing significant increase in the sensitivity of such fibers. At doses of less than 1 Gy none of these investigations have addressed the relationship between dose response and TL glow peak behavior of erbium (Er)-doped silica cylindrical fibers (CF). For x-rays obtained at accelerating potentials from 70 to 130 kVp, delivering doses of between 0.1 and 0.7 Gy, present study explores the issue of dose response, special attention being paid to determination of the kinetic parameters and dosimetric peak properties of Er-doped CF. The effect of dose response on the kinetic parameters of the glow peak has been compared against other fiber types, revealing previously misunderstood connections between kinetic parameters and radiation dose. Within the investigated dose range there was an absence of supralinearity of response of the Er-doped silica CF, instead sub-linear response being observed. Detailed examination of glow peak response and kinetic parameters has thus been shown to shed new light of the rarely acknowledged issue of the limitation of TL kinetic model and sub-linear dose response of Er-doped silica CF.

Enhanced upconversion emission in colloidal (NaYF4:Er(3+))/NaYF4 core/shell nanoparticles excited at 1523 nm.

In this work, we report on efficient visible and near-IR upconversion emissions in colloidal hexagonal-phase core/shell NaYF4:Er(3+)/NaYF4 nanoparticles (∼38 nm) under IR laser excitation at 1523 nm. Varying amounts of Er(3+) dopants were introduced into the core NaYF4:Er(3+) nanoparticles, revealing an optimized Er(3+) concentration of 10% for the highest luminescent efficiency. An inert epitaxial shell layer of NaYF4 grown onto the core of the NaYF4:Er(3+) 10% nanoparticle increased its upconversion emission intensity fivefold due to suppression of surface-related quenching mechanisms, yielding the absolute upconversion efficiency to be as high as ∼3.9±0.3% under an excitation density of 18 W/cm(2). The dependence of the intensity of upconversion emission peaks on laser excitation density in the core/shell nanoparticle displayed "saturation effects" at low excitation density in the range of 1.5-18 W/cm(2), which again demonstrates high upconversion efficiency.

Contrasting behaviour of the co-activators in the luminescence spectra of Y2O2S:Tb3+,Er3+ nanometre sized particles under UV and red light excitation.

Nanometre sized particles of terbium and erbium co-doped yttrium oxysulfide up-converting phosphors were prepared by a urea homogeneous-precipitation method. Results from X-ray powder diffraction (XRPD), scanning electron microscopy (SEM) and photoluminescence spectroscopy studies on the microstructure and luminescent properties of the materials are reported. Upconversion emission was observed from the Er(3+) cations when particles were excited with laser light of 632.8 nm wavelength. Under these conditions no interactions between the Er(3+) cations and the Tb(3+) cations were observed. In contrast there was evidence from the Stokes emission of the Er(3+) cations under 254 nm excitation for an interaction between the Er(3+) and Tb(3+) cations reducing intensity of the latter's blue and green emission bands by cross relaxation processes.

Radiation-resistant erbium-doped-nanoparticles optical fiber for space applications.

We demonstrate for the first time a radiation-resistant Erbium-Doped Fiber exhibiting performances that can fill the requirements of Erbium-Doped Fiber Amplifiers for space applications. This is based on an Aluminum co-doping atom reduction enabled by Nanoparticules Doping-Process. For this purpose, we developed several fibers containing very different erbium and aluminum concentrations, and tested them in the same optical amplifier configuration. This work allows to bring to the fore a highly radiation resistant Erbium-doped pure silica optical fiber exhibiting a low quenching level. This result is an important step as the EDFA is increasingly recognized as an enabling technology for the extensive use of photonic sub-systems in future satellites.

High yield production of the medical radioisotope 167Tm by the 167Er(d,2n) reaction.

As part of our systematic comparison of (p,n) and (d,2n) reactions, the excitation functions of the (167)Er(d,2n)(167)Tm production reaction and reactions leading to Tm radio-impurities were investigated up to 20 MeV. A stacked foil irradiation technique and γ-ray spectroscopy is used. The measured excitation functions are compared with results of ALICE-D, EMPIRE-D and TALYS reaction model codes and with data from our earlier investigations on natural Er. Thick target yields and contamination levels are discussed. A comparison with other charged particle production routes for (167)Tm shows that deuteron induced reactions are not competitive.

Experimental study of the excitation functions of proton induced nuclear reactions on (167)Er for production of medically relevant (167)Tm.

(167)Tm (T(1/2)=9.25d) is a candidate radioisotope for medical therapy and diagnostics due to its Auger-electron and low-energy X- and gamma-ray emission. Excitation functions of the (167)Er(p,n)(167)Tm reaction and (168)Er(p,n)(168)Tm, (167)Er(p,2n)(166)Tm, (166)Er(p,2n)(165)Tm disturbing reactions were measured up to 15MeV by using the stacked foil irradiation technique and gamma-ray spectroscopy. The measured excitation functions agree well with the results of ALICE-IPPE, EMPIRE-II and TALYS nuclear reaction model codes. The thick target yield of (167)Tm in the 15-8MeV energy range is 6.9MBq/microAh. A short comparison of charged particle production routes of (167)Tm is given.

Active waveguides written by femtosecond laser irradiation in an erbium-doped phospho-tellurite glass.

We report on fs-laser micromachining of active waveguides in a new erbium-doped phospho-tellurite glass by means of a compact cavity-dumped Yb-based writing system. The spectroscopic properties of the glass were investigated, and the fs-laser written waveguides were characterized in terms of passive as well as active performance. In particular, internal gain was demonstrated in the whole C+L band of optical communications (1530- 1610 nm).