In vivo toxicity studies of europium hydroxide nanorods in mice

Europium-Doped 3D Dimensional Porous Calcium Phosphate Scaffolds as a Strategy for Facilitating the Comprehensive Regeneration of Bone Tissue: In Vitro and In Vivo

In response to the challenges faced by clinicians treating bone defects caused by various factors, various bone repair materials have been investigated, but the efficiency of bone healing still needs to be improved due to the acting of scaffolds only in a single stage of bone tissue regeneration. We investigated the potential of a novel 3D scaffold to support different stages of bone tissue regeneration, including initial inflammation, proliferation, and remodeling. Eu (0, 0.5, 2, 3.5, 5, and 6.5%) was added to calcium polyphosphate to obtain 3D porous network-doped Eu calcium polyphosphate (EuCPP) scaffolds with ideal mechanical strength and pore size. Both in vitro and in vivo experiments proved that Eu3+ released from 5% EuCPP scaffolds could significantly promote the migration and proliferation of bone marrow stromal cells which effectively promote angiogenesis; 5% EuCPP could significantly upregulate the ratio of OPG/RANKL in MC3T3-E1 and promote the secretion of osteogenic-related growth factors (ALP and OPN) from MC3T3-E1, indicating the potential of the scaffold to inhibit bone resorption and promote bone formation. In conclusion, 5% EuCPP possesses the biological properties of pro-angiogenesis, anti-inflammation, pro-osteogenesis, and inhibiting bone resorption, which may provide a sustained positive effect throughout the process of bone tissue repair.

Microwave-assisted synthesis of Ni-doped europium hydroxide for photocatalytic degradation of 4-nitrophenol

Microwave-assisted synthesis method was used to prepare europium hydroxide (Eu(OH)3) and different percentages of 1, 5, and 10 % nickel-doped Eu(OH)3 (Ni-Eu(OH)3) nanorods (NRs). X-ray diffraction study showed a hexagonal phase with an average crystallite size in the range of 21 - 35 nm for Eu(OH)3 and Ni-Eu(OH)3 NRs. FT-IR and Raman studies also confirmed the synthesis of Eu(OH)3 and Ni-Eu(OH)3. The synthesized materials showed rod-like morphology with an average length and diameter between 27 - 50 nm and 8 - 13 nm, respectively. The band gap energies of Ni-Eu(OH)3 NRs were reduced (4.06 - 3.50 eV), which indicates that the doping of Ni2+ ions has influenced the band gap energy of Eu(OH)3. The PL study exhibited PL quenching with Ni doping. The photocatalytic degradation of 4-nitrophenol (4-NP) by the synthesized materials under UV light irradiation was investigated, in which 10 % Ni-Eu(OH)3 NRs showed the best response. A kinetic study was also conducted which shows pseudo-first-order kinetics. Based on this, Ni-Eu(OH)3 NRs have shown a potential to be a UV-light active material for photocatalysis.

Determining toxicity of europium oxide nanoparticles in immune cell components and hematopoiesis in dominant organs in mice: Role of lysosomal fluid interaction

Extensive application of rare earth element oxide nanoparticles (REE NPs) has raised a concern over the possible toxic health effects after human exposure. Once entering the body, REE NPs are primarily processed by phagocytes in particular macrophages and undergo biotic phosphate complexation in lysosomal compartment. Such biotransformation affects the target organs and in vivo fate of REE NPs after escaping the lysosomes. However, the immunomodulatory effects of intraphagolysosomal dissolved REE NPs remains insufficient. Here, europium oxide (Eu2O3) NPs were pre-incubated with phagolysosomal simulant fluid (PSF) to mimic the biotransformation of europium oxide (p-Eu2O3) NPs under acid phagolysosome conditions. We investigated the alteration in immune cell components and the hematopoiesis disturbance on adult mice after intravenous administration of Eu2O3 NPs and p-Eu2O3 NPs. Our results indicated that the liver and spleen were the main target organs for Eu2O3 NPs and p-Eu2O3 NPs. Eu2O3 NPs had a much higher accumulative potential in organs than p-Eu2O3 NPs. Eu2O3 NPs induced more alterations in immune cells in the spleen, while p-Eu2O3 NPs caused stronger response in the liver. Regarding hematopoietic disruption, Eu2O3 NPs reduced platelets (PLTs) in peripheral blood, which might be related to the inhibited erythrocyte differentiation in the spleen. By contrast, p-Eu2O3 NPs did not cause significant disturbance in peripheral PLTs. Our study demonstrated that the preincubation with PSF led to a distinct response in the immune system compared to the pristine REE NPs, suggesting that the potentially toxic effects induced by the release of NPs after phagocytosis should not be neglected, especially when evaluating the safety of NPs application in vivo.

Toxicity study of pro-angiogenic casein manganese oxide nanoparticles: an in vitro and in vivo approach

Recently, we have demonstrated casein manganese oxide nanoparticles (CMnNP) that exhibit pro-angiogenic property established through different in vitro and in vivo experiments. The CMnNP was explored for therapeutic angiogenesis for treatment of wounds and recovery of hindlimb ischemia in pre-clinical mouse prototypical. It is well known that to translate any therapeutic nanoparticle for future clinical applications, their biosafety evaluation in small and large animals is essential. Herein, in the current study, the biosafety and bioavailability of the CMnNP have been explored by a systematic toxicity profiling study in C57BL/6J mice model. Initially, the in vitro cytotoxic effects of CMnNP were validated in RAW 264.7 cells. Later, the CMnNP was administered intraperitoneally with different doses (50, 300, and 2000 mg/kg b.wt./day) at different time points of exposure (acute: 2 weeks, sub-chronic: 4 weeks as well as chronic exposure: 8 and 20 weeks) with reference to the maximum tolerable dose (MTD) of CMnNP as per the OECD guidelines. The blood hematological and serum biochemical parameters of CMnNP treatment groups indicate negligible changes similar to untreated group. The histopathological examination of CMnNP-treated vital organs (lung, spleen, liver, brain, kidney, and heart) illustrates no major changes even at higher doses. Further, the biodistribution and excretion study depicts normal clearance of CMnNP. Additionally, the serum cytokine levels were normal in the therapeutic dose of CMnNP. The results altogether indicate that the non-toxic nature of CMnNP makes them useful as future therapeutic angiogenic agent for the treatment of various diseases where angiogenesis plays an important role.

Nanotechnology in coronary heart disease

Coronary heart disease (CHD) is one of the major causes of death and disability worldwide, especially in low- and middle-income countries and among older populations. Conventional diagnostic and therapeutic approaches have limitations such as low sensitivity, high cost and side effects. Nanotechnology offers promising alternative strategies for the diagnosis and treatment of CHD by exploiting the unique properties of nanomaterials. In this review, we use bibliometric analysis to identify research hotspots in the application of nanotechnology in CHD and provide a comprehensive overview of the current state of the art. Nanomaterials with enhanced imaging and biosensing capabilities can improve the early detection of CHD through advanced contrast agents and high-resolution imaging techniques. Moreover, nanomaterials can facilitate targeted drug delivery, tissue engineering and modulation of inflammation and oxidative stress, thus addressing multiple aspects of CHD pathophysiology. We discuss the application of nanotechnology in CHD diagnosis (imaging and sensors) and treatment (regulation of macrophages, cardiac repair, anti-oxidative stress), and provide insights into future research directions and clinical translation. This review serves as a valuable resource for researchers and clinicians seeking to harness the potential of nanotechnology in the management of CHD. STATEMENT OF SIGNIFICANCE: Coronary heart disease (CHD) is the one of leading cause of death and disability worldwide. Nanotechnology offers new strategies for diagnosing and treating CHD by exploiting the unique properties of nanomaterials. This review uses bibliometric analysis to uncover research trends in the use of nanotechnology for CHD. We discuss the potential of nanomaterials for early CHD detection through advanced imaging and biosensing, targeted drug delivery, tissue engineering, and modulation of inflammation and oxidative stress. We also offer insights into future research directions and potential clinical applications. This work aims to guide researchers and clinicians in leveraging nanotechnology to improve CHD patient outcomes and quality of life.

Toxicological evaluation of therapeutically active zinc oxide nanoflowers in pre-clinical mouse model

Our earlier reports established that zinc oxide nanoflowers (ZONF) show significant pro-angiogenic properties, where reactive oxygen species, nitric oxide and MAPK-AKT-eNOS cell signaling axis play an essential task. Considering the significance of angiogenesis in healthcare, our research group has recently demonstrated the in vivo therapeutic application of ZONF (10 mg/kg b.w.) for treating peripheral artery disease. Moreover, based on the angio-neural crosstalk between vascular and neuronal systems, we have further demonstrated the neuritogenic and neuroprotective characteristics of pro-angiogenic nanoflowers (10 mg/kg b.w.) for the treatment of cerebral ischemia. However, it is crucial for a therapeutic material to be non-toxic for its practical clinical applications and therefore assessment of its in vivo toxicity and adverse effect is highly important. Herein, for the first time, we investigate a detailed nanotoxicology of therapeutically active ZONF in Swiss albino mice to evaluate their safety profile and comprehend their aspects for future clinical applications. The maximum tolerated dose (MTD) of ZONF was found to be 512.5 mg/kg b.w. which was employed for acute exposure (2 weeks), showing slight toxicity. However, sub-chronic (4 weeks) and long term chronic (8-12 weeks) studies of nanoflowers exhibited their non-toxic nature particularly at lower therapeutic doses (1-10 mg/kg b.w.). Additionally, in depth genotoxicity study revealed that lower therapeutic dose of ZONF (10 mg/kg b.w.) did not exhibit significant toxicity even in genetic level. Overall, the present nanotoxicology of ZONF suggests their high biocompatible nature at therapeutic dose, offering the basis of their future clinical applications in ischemic and other vascular diseases.

The biological functions of europium-containing biomaterials: A systematic review

The biological functions of rare-earth elements (REEs) have become a focus of intense research. Recent studies have demonstrated that ion doping or alloying of some REEs can optimize the properties of traditional biomaterials. Europium (Eu), which is an REE with low toxicity and good biocompatibility, has promising applications in biomedicine. This article systematically reviews the osteogenic, angiogenic, neuritogenic, antibacterial, and anti-tumor properties of Eu-containing biomaterials, thereby paving the way for biomedical applications of Eu. Data collection for this review was completed in October 2022, and 30 relevant articles were finally included. Most articles indicated that doping of Eu ions or Eu-compound nanoparticles in biomaterials can improve their osteogenic, angiogenic, neuritogenic, antibacterial, and anti-tumor properties. The angiogenic, antibacterial, and potential neuritogenic effects of Eu(OH)₃ nanoparticles have also been demonstrated.

Lanthanide-based metal-organic frameworks solidified by gelatin-methacryloyl hydrogels for improving the accuracy of localization and excision of small pulmonary nodules

The localization of invisible and impalpable small pulmonary nodules has become an important concern during surgery, since current widely used techniques for localization have a number of limitations, such as invasive features of hookwires and microcoils, and rapid diffusion after injection of indocyanine green (ICG). Lanthanide-based metal–organic frameworks (MOFs) have been proven as potential fluorescent agents because of their prominent luminescent characteristics, including large Stokes shifts, high quantum yields, long decay lifetimes, and undisturbed emissive energies. In addition, lanthanides, such as Eu, can efficiently absorb X-rays for CT imaging. In this study, we synthesized Eu-UiO-67-bpy (UiO = University of Oslo, bpy = 2,2'-bipyridyl) as a fluorescent dye with a gelatin-methacryloyl (GelMA) hydrogel as a liquid carrier. The prepared complex exhibits constant fluorescence emission owing to the luminescent characteristics of Eu and the stable structure of UiO-67-bpy with restricted fluorescence diffusion attributed to the photocured GelMA. Furthermore, the hydrogel provides stiffness to make the injection site tactile and improve the accuracy of localization and excision. Finally, our complex enables fluorescence-CT dual-modal imaging of the localization site.

Eu-Doped Zeolitic Imidazolate Framework-8 Modified Mixed-Crystal TiO2 for Efficient Removal of Basic Fuchsin from Effluent

Zeolitic imidazolate framework-8 (ZIF-8) was doped with a rare-earth metal, Eu, using a solvent synthesis method evenly on the surface of a mixed-crystal TiO2(Mc-TiO2) structure in order to produce a core-shell structure composite ZIF-8(Eu)@Mc-TiO2 adsorption photocatalyst with good adsorption and photocatalytic properties. The characterisation of ZIF-8(Eu)@Mc-TiO2 was performed via X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller analysis (BET) and ultraviolet-visible light differential reflectance spectroscopy (UV-DRs). The results indicated that Eu-doped ZIF-8 was formed evenly on the Mc-TiO2 surface, a core-shell structure formed and the light-response range was enhanced greatly. The ZIF-8(Eu)@Mc-TiO2 for basic fuchsin was investigated to validate its photocatalytic performance. The effect of the Eu doping amount, basic fuchsin concentration and photocatalyst dosage on the photocatalytic efficiency were investigated. The results revealed that, when 5%-Eu-doped ZIF-8(Eu)@Mc-TiO2 (20 mg) was combined with 30 mg/L basic fuchsin (100 mL) under UV irradiation for 1 h, the photocatalytic efficiency could reach 99%. Further, it exhibited a good recycling performance. Thus, it shows certain advantages in its degradation rate and repeatability compared with previously reported materials. All of these factors suggested that, in an aqueous medium, ZIF-8(Eu)@Mc-TiO2 is an eco-friendly, sustainable and efficient material for the photocatalytic degradation of basic fuchsin.

Electrochemical synthesis of EuVO4 for the adsorption of U(VI): Performance and mechanism

The efficient removal of uranium from aqueous solution remains of great challenge in securing water environment safety. In this paper, we reported a high temperature electrochemical method for the preparation of EuVO₄ with different morphologies from rare earth oxides and vanadate, which solved the problems of rare earth and vanadium recovery. The effects of pH, ionic strength, contact time, initial concentration and reaction temperature on the adsorption of U(VI) by prepared adsorbent were studied by static batch experiments. When the concentration of U(VI) standard is 100 mg g^-1, the maximum adsorption capacity of EuVO₄ is 276.16 mg g^-1. The adsorption mechanism was elucidated with zeta potential and XPS: 1) negatively charged EuVO₄ attracted UO₂²⁺ by electrostatic attraction; 2) exposed Eu, V, and O atoms complexed with U(VI) through coordination; 3) the hybrid of Eu was complex, which accommodated different electrons to interact. In the multi-ion system with Al³⁺, Zn²⁺, Cu²⁺, Ni²⁺, Cr²⁺ and Mn²⁺, EuVO₄ also showed good selective adsorption properties for U(VI). Five adsorption and desorption cycle experiments demonstrated that EuVO₄ possessed good renewable performance.

Vacancy-Induced Visible Light-Driven Fluorescence in Toxic Ion-Free Resorbable Magnetic Calcium Phosphates for Cell Imaging Applications

Multifunctional nanosized particles are very beneficial in the field of biomedicine. Bioactive and highly biocompatible calcium phosphate (CaP) nanoparticles (∼50 nm) exhibiting both superparamagnetic and fluorescence properties were synthesized by incorporating dual ions (Fe³⁺ and Sr²⁺) in HAp (hydroxyapatite) [Ca₁₀(PO₄)₆(OH)₂]. Insertion of Fe³⁺ creates oxygen vacancies at the PO₄^3- site, thereby destabilizing the structure. Thus, in order to maintain the structural stability, Sr²⁺ has been incorporated. This incorporation of Sr²⁺ leads to an intense emission at 550 nm. HAp nanoparticles when subjected to thermal treatment (800 °C) transform to β-TCP, exhibiting emission at 710 nm due to the emergence of an intermediate band. Moreover, these nanoparticles exhibit fluorescence in visible light when compared to the other UV and IR fluorescence excitation sources which could damage the tissues. The synthesis involving the combination of ultrasound and microwave techniques resulted in the distribution of Fe³⁺ in the interstitial sites of CaP, which is responsible for the excellent fluorescent properties. Moreover, thermally treated CaP becomes superparamagnetic, without affecting the desired optical properties. The bioactive, biocompatible, magnetic, and fluorescent properties of this resorbable CaP which is free from toxic heavy metals (Eu, Gd, etc.) could help in overcoming the long-term cytotoxicity. This could also be useful in tracking the location of the nanoparticles during drug delivery and magnetic hyperthermia. The bioactive fluorescent CaP nanoparticle helps in monitoring the bone growth and in addition, it could be employed in cell imaging applications. The in vitro MCF-7 imaging using the nanoparticles after 24 h of uptake at 465 nm evidences the bioimaging capability of the prepared nanoparticles. The reproducibility of the defect level is essential for the defect-induced emission properties. The synthesis of nontoxic fluorescent CaP is highly reproducible with the present synthesis method. Hence, it could be safely employed in various biomedical applications.

Luminescence Sensing Method for Degradation Analysis of Bioactive Glass Fibers

The effects of Sm³⁺ content on the optical properties and bioactivity of 13-93 bioactive glass were presented. Sm³⁺ doped glass fibers drawn from bioactive glass were analyzed in simulated body fluid (SBF) for the determination of ion release. Optical analysis of the Sm³⁺ ions in bioactive glass fibers was used for degradation monitoring. While the fibers were immersed in SBF solution, changes in their luminescence spectra under 405 nm laser excitation were measured continuously for 48 h. The morphology of the fibers after the immersion process was determined by SEM/EDS. It was shown that the proposed approach to the analysis of changes in Sm³⁺ ion luminescence is a sensitive method for the monitoring of degradation processes and the formation of hydroxycarbonate-apatite (HCA) layers on glass fiber surfaces. SEM/EDS measurements showed a significant deterioration on the surface of the fibers and the formation of HCA on 13-93_02Sm bioactive glass. The optical analysis of the time constant indicated that bioactive glass fibers doped with 2 %mol Sm³⁺ degrade at a rate almost five times slower than 13-93_02Sm.

A mini-review of X-ray photodynamic therapy (XPDT) nonoagent constituents' safety and relevant design considerations

Conventional photodynamic therapy (PDT) has proved effective in the management of primary tumors and individual metastases. However, most cancer mortality arises from wide-spread multiple metastases. The latter has thus become the principal target in oncology, and X-ray induced photodynamic therapy (XPDT or PDTX) offers a great solution for adapting the PDT principle to deep tumors and scattered metastases. Developing agents capable of being excited by X-rays and emitting visible light to excite photosensitizers is based on challenging physical and chemical technologies, but there are fundamental biological limitations that are to be accounted for as well. In the present review, we have established eight major groups of safety determinants of NPs encompassing 22 parameters of clinical applicability of XPDT nanoparticulate formulations. Most, if not all, of these parameters can be accounted for and optimized during the design and development of novel XPDT nanoparticles.

Anti-angiogenic vanadium pentoxide nanoparticles for the treatment of melanoma and their in vivo toxicity study

In recent days, vanadium complexes and nanoparticles have received sustainable attention owing to their vast applications in different fields. In the present study, we report a facile approach for the synthesis of irregular dumbbell shaped vanadium pentoxide nanoparticles (V₂O₅ NPs: 30-60 nm) via the polyol-induced microwave irradiation process along with calcination. The as-synthesized nanoparticles were characterized using various physico-chemical techniques (e.g. XRD, TEM, FT-IR, DLS and XPS). The cell viability assay showed that V₂O₅ NPs could efficiently inhibit the proliferation of different cancer cells (B16F10, A549, and PANC1), depicting their anti-proliferative activity. However, V₂O₅ NPs did not exert significant cytotoxicity to the normal cells (CHO, HEK-293 and NRK-49F), suggesting their biocompatible nature. Interestingly, these nanoparticles inhibited the proliferation and migration of the endothelial cells (HUVECs and EA.hy926) and disrupted the blood vasculature in a chick embryo model, indicating their anti-angiogenic properties. The mechanistic study revealed that the effective internalization of V₂O₅ NPs generated intracellular reactive oxygen species (ROS) which in turn up-regulated p53 protein and down-regulated survivin protein in cancer cells, leading to the apoptosis process. Furthermore, the administration of V₂O₅ NPs to melanoma bearing C57BL6/J mice significantly increased their survivability as compared to the control untreated tumor bearing mice, exhibiting the therapeutic potential of the nanoparticles against melanoma. Additionally, the in vivo toxicity study demonstrated no toxic effect in mice upon sub-chronic exposure to V₂O₅ NPs. Altogether, we strongly believe that V₂O₅ NPs could intrinsically provide a new direction for alternative therapeutic treatment strategies for melanoma and other cancers by employing their anti-angiogenic properties in the future.

Potential Therapeutic Application of Zinc Oxide Nanoflowers in the Cerebral Ischemia Rat Model through Neuritogenic and Neuroprotective Properties

Neuritogenesis, a complex process of the sprouting of neurites, plays a vital role in the structural and functional restoration of cerebral ischemia-injured neuronal tissue. Practically, there is no effective long-term treatment strategy for cerebral ischemia in clinical practice to date due to several limitations of conventional therapies, facilitating the urgency to develop new alternative therapeutic approaches. Herein, for the first time we report that pro-angiogenic nanomaterials, zinc oxide nanoflowers (ZONF), exhibit neuritogenic activity by elevating mRNA expression of different neurotrophins, following PI3K/Akt-MAPK/ERK signaling pathways. Further, ZONF administration to global cerebral ischemia-induced Fischer rats shows improved neurobehavior and enhanced synaptic plasticity of neurons via upregulation of Neurabin-2 and NT-3, revealing their neuroprotective activity. Altogether, this study offers the basis for exploitation of angio-neural cross talk of other pro-angiogenic nano/biomaterials for future advancement of alternative treatment strategies for cerebral ischemia, where neuritogenesis and neural repair are highly critical.

Comparative in vitro study on binary Mg-RE (Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) alloy systems

Correct selection of alloying elements is important for developing novel biodegradable magnesium alloys with superior mechanical and biological performances. In contrast to various reports on nutrient elements (Ca, Zn, Sr, etc.) as alloying elements of biomedical magnesium alloys, there is limited information about how to choose the right rare earth elements (REEs) as alloying elements of magnesium. In this work, 16 kinds of REEs were individually added into Mg, including Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Du, Ho, Er, Tm, Yb and Lu, to fabricate binary Mg-RE model alloys with different composition points. Under the same working history, comparative studies were undertaken and the impact of each kind of rare earth element on the microstructure, mechanical property, corrosion behavior and biocompatibility of Mg were investigated. The corresponding influence level for the 16 kinds of REEs were ranked. The results showed that the second phases were detected in some Mg-RE alloys, which were mainly composed of Mg₁₂RE. By adding different REEs into Mg with proper contents, the mechanical properties of resulting Mg-RE binary alloys could be adjusted in wide range. The corrosion resistance of Mg-light REE alloys was generally better than Mg-heavy REE alloys. As for biocompatibility, Mg-RE model alloys showed no cytotoxic effect on MC3T3-E1 cells. The hemolysis rates of all experimental Mg-RE model alloys were lower than 5% except for Mg-Lu alloy model. In general, the addition of different REEs into Mg could improve its performance from different aspects. This work provides a better understanding on suitable REEs as alloying elements for magnesium, and the future R&D direction on biomedical Mg-RE alloys was proposed. STATEMENT OF SIGNIFICANCE: In contrast to various reports on nutrient elements (Ca, Zn, Sr, etc.) as alloying elements of biomedical magnesium alloys, until now there is limited information about how to choose the right rare earth elements (REEs) as alloying elements of magnesium. In this work, comparative studies were undertaken by individually adding 16 kinds of REEs, including Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Du, Ho, Er, Tm, Yb and Lu, into Mg to fabricate binary Mg-RE model alloys, with different composition points, then the impact of each kind of rare earth element on the microstructure, mechanical property, corrosion behavior and biocompatibility of Mg under the same working history were investigated, and the corresponding influence level for the 16 kinds of REEs were ranked. This work provides a better understanding on suitable REEs as alloying elements for magnesium, and the future R&D direction on biomedical Mg-RE alloys was proposed.

Elucidating the role of size of hydroxyl apatite particles toward the development of competent antiosteoporotic bioceramic materials: In vitro and in vivo studies

Osteoporosis caused by overdose of steroids is one of the major concerns for the orthopedic surgeons. Current therapeutic strategies offer limited success due to their inability to regenerate damaged bone at osteoporosis site. Therefore, there is an urgent need to develop a material having bone regeneration ability and also, ability to cure osteoporosis simultaneously. In this work, nanosized and microsized hydroxyl apatite (HAp) particles doped with europium (Eu) were prepared for diagnostic and therapeutic applications in biomedical engineering. Particles were characterized by X-ray diffraction to confirm the formation of HAp phase and transmission electron microscopy technique has been used to explore the size of microparticle and nanoparticle. In vitro release of antibiotic drug and degradation behavior in two different pHs of phosphate buffered saline was checked. Controlled drug release behavior and conversion of degraded ions into HAp is estimated by Higuchi's and 3D diffusion model, respectively. Osteoporosis was induced in 36 female Wistar rats by administering dexamethasone once a week for four consecutive weeks. Rats were treated with different doses of nano-HAp (25, 50, and 100 μg/kg intravenous single dose) and single dose of microsized HAp (100 μg/kg). After treatment, authors have evaluated sensitive biochemical markers of bone in serum. Continuous improvement in ultimate stiffness and Young's modulus of femur shaft of rats was observed with the increase in the dose of nano-HAp from 25 to 100 μg/kg. Results strongly suggest that europium-doped nano-HAp is more effective for treating severe osteoporosis in humans. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1723-1735, 2019.

Engineered Nanoparticles for Effective Redox Signaling During Angiogenic and Antiangiogenic Therapy

SIGNIFICANCE

Redox signaling plays a vital role in regulating various cellular signaling pathways and disease biology. Recently, nanomedicine (application of nanotechnology in biology and medicine) has been demonstrated to regulate angiogenesis through redox signaling. A complete understanding of redox signaling pathways influenced angiogenesis/antiangiogenesis triggered by therapeutic nanoparticles is extensively reviewed in this article. Recent Advances: In recent times, nanomedicines are regarded as the Trojan horses that could be employed for successful drug delivery, gene delivery, peptide delivery, disease diagnosis, and others, conquering barriers associated with conventional theranostic approaches.

CRITICAL ISSUES

Physiological angiogenesis is a tightly regulated process maintaining a balance between proangiogenic and antiangiogenic factors. The redox signaling is one of the main factors that contribute to this physiological balance. An aberrant redox signaling cascade can be caused by several exogenous and endogenous factors and leads to reduced or augmented angiogenesis that ultimately results in several disease conditions.

FUTURE DIRECTIONS

Redox signaling-based nanomedicine approach has emerged as a new platform for angiogenesis-related disease therapy, where nanoparticles promote angiogenesis via controlled reactive oxygen species (ROS) production and antiangiogenesis by triggering excessive ROS formation. Recently, investigators have identified different efficient nano-candidates, which modulate angiogenesis by controlling intracellular redox molecules. Considering the importance of angiogenesis in health care a thorough understanding of nanomedicine-regulated redox signaling would inspire researchers to design and develop more novel nanomaterials that could be used as an alternative strategy for the treatment of various diseases, where angiogenesis plays a vital role.

Screening of acute and sub-chronic dermal toxicity of Calendula officinalis L essential oil

The objective of the study is to access the safety of Calendula essential oil by studying acute and sub-chronic dermal toxicity. The dermal toxicities of Calendula essential oil were evaluated in accordance with OECD guidelines number 402 and 411 respectively. The animals were exposed to Calendula officinalis (CO) essential oil dose of 20 mL/kg body weight for acute dermal toxicity, whereas for dermal sub-chronic toxicity study, rats were exposed to CO oil 2.5, 5 and 10 mL/kg body weight, respectively, for 7 times in a week for 90 days. The parameters studies included CNS stimulation, depression, hematological parameters (RBC, WBC, Hb, Lymphocyte % etc), biochemical parameters (total protein, albumin, total bilirubin, ALP, AST, etc), relative organ weight, necropsy and histopathology. In toxicity studies, all animals exhibited normal behavior without any change in hematology, blood biochemistry, necroscopical and histopathology. The no observed effect level (NOEL) and no observed adverse effect level (NOAEL) of CO oil were 2.5 and 10 mg/kg/day, respectively. CO oil is under the herbal medicinal product according to the European Medicines Agency with the claim of an LD₅₀ value of 20 mL/kg body weight. The result indicates that CO essential oil did not produce any significant toxic effects.

In-vitro cytotoxicity and cellular uptake studies of luminescent functionalized core-shell nanospheres

Monodispersed luminescent functionalized core-shell nanospheres (LFCSNs) were successfully synthesized and investigated for their cyto-toxic effect on human liver hepatocellular carcinoma cell line (HepG2 cells) by adopting MTT, DNA Ladder, TUNEL assay and qPCR based gene expressions through mRNA quantifications. The TUNEL and DNA ladder assays suggested an insignificant apoptosis in HepG2 cells due to the LFCSNs treatment. Further, the qPCR results also show that the mRNA expressions of cell cycle checkpoint gene p53 and apoptosis related gene (caspase-9) was up-regulated, while the antiapoptotic gene BCl-2 and apoptosis related genes FADD and CAS-3 (apoptosis effecter gene) were down-regulated in the LFCSNs treated cells. The nanospheres that were loaded into the cells confirm their intracellular uptake by light and fluorescent spectro-photometry and microscopy imaging analysis. The loaded nanospheres demonstrate an absolute resistance to photo-bleaching, which were applied for dynamic imaging to real-time tracking in-vitro cell migratory activity for continuous 24 and 48 h durations using a time-lapsed fluorescent microscope. These properties of LFCSNs could therefore promote applications in the area of fluorescent protein biolabeling and drug-delivery.

Engineered fusion protein-loaded gold nanocarriers for targeted co-delivery of doxorubicin and erbB2-siRNA in human epidermal growth factor receptor-2+ ovarian cancer

Gold nanoparticle based targeted drug delivery system (TDDS) for transporting DX and siRNA in HER2+ ovarian cancer.

Therapeutic application of anti-angiogenic nanomaterials in cancers

Angiogenesis, the formation of new blood vessels from pre-existing vasculature, plays a vital role in physiological and pathological processes (embryonic development, wound healing, tumor growth and metastasis). The overall balance of angiogenesis inside the human body is maintained by pro- and anti-angiogenic signals. The processes by which drugs inhibit angiogenesis as well as tumor growth are called the anti-angiogenesis technique, a most promising cancer treatment strategy. Over the last couple of decades, scientists have been developing angiogenesis inhibitors for the treatment of cancers. However, conventional anti-angiogenic therapy has several limitations including drug resistance that can create problems for a successful therapeutic strategy. Therefore, a new comprehensive treatment strategy using antiangiogenic agents for the treatment of cancer is urgently needed. Recently researchers have been developing and designing several nanoparticles that show anti-angiogenic properties. These nanomedicines could be useful as an alternative strategy for the treatment of various cancers using anti-angiogenic therapy. In this review article, we critically focus on the potential application of anti-angiogenic nanomaterial and nanoparticle based drug/siRNA/peptide delivery systems in cancer therapeutics. We also discuss the basic and clinical perspectives of anti-angiogenesis therapy, highlighting its importance in tumor angiogenesis, current status and future prospects and challenges.

Synergistic Effect of Human Serum Albumin and Fullerene on Gd-DO3A for Tumor-Targeting Imaging

A macromolecular magnetic resonance imaging (MRI) contrast agent was successfully synthesized by conjugating the gadolinium/1,4,7,10-tetraazacyclododecane-1,4,7-tetracetic acid complex (Gd-DO3A) with 6,6-phenyl-C61 butyric acid (PC61BA) and upon further modification with human serum albumin (HSA). The final product, PC61BA-(Gd-DO3A)/HSA, has a high stability and exhibits a much higher relaxivity (r1 = 89.1 mM(-1) s(-1) at 0.5 T, 300 K) than Gd-DO3A (r1 = 4.7 mM(-1) s(-1)) does under the same condition, producing the synergistic positive effect of HSA and C60 on the relaxivity of Gd-DO3A. The in vivo MR images of PC61BA-(Gd-DO3A)/HSA-treated tumor-bearing mice show strong signal enhancement for the tumor area due to the enhanced permeability and retention effect. The maximum accumulation of PC61BA-(Gd-DO3A)/HSA at the tumor site was achieved at 4 h postinjection, which may guide surgery. The results from the hematology and histological observations indicate that PC61BA-(Gd-DO3A)/HSA has no obvious toxicity in vivo. These unique properties of PC61BA-(Gd-DO3A)/HSA enable them to be highly efficient for tumor-targeting MRI in vivo, possibly providing a good solution for tumor diagnosis.

Europium-Containing Mesoporous Bioactive Glass Scaffolds for Stimulating in Vitro and in Vivo Osteogenesis

Bone tissue engineering offers a possible strategy for regenerating large bone defects, in which how to design beneficial scaffolds for accelerating bone formation remains significantly challenging. Europium, as an important rare earth element, has been used as a solid-state lighting material. However, there are few reports on whether Eu can be used for labeling bone tissue engineering scaffolds, and its biological effect on bone cells and bone tissue regeneration is unknown. In this study, we incorporated Eu into mesoporous bioactive glass (Eu-MBG) scaffolds by an in situ cotemplate method to achieve a bifunctional biomaterial with biolabeling and bone regeneration. The prepared Eu-MBG scaffolds have highly interconnective large pores (300-500 μm), a high specific surface area (140-290 m(2)/g), and well-ordered mesopores (5 nm) as well as uniformly distributed Eu. The incorporation of 2-5 mol % Eu into MBG scaffolds gives them a luminescent property. The in vitro degradation of Eu-MBG scaffolds has a functional effect on the change of the luminescence intensity. In addition, Eu-MBG can be used for labeling bone marrow stromal cells (BMSCs) in vitro and still presents a distinct luminescence signal in deep bone tissues in vivo to label new bone tissue via release of Eu ions. Furthermore, the incorporation of different contents of Eu (1, 2, and 5 mol %) into MBG scaffolds significantly enhances the osteogenic gene expression of BMSCs in the scaffolds. The Eu- and Si-containing ionic products released from Eu-MBG scaffolds distinctly promote the osteogenic differentiation of BMSCs. Critically sized femur defects in ovariectomized (OVX) rats are created to simulate an osteoporotic phenotype. The results show that Eu-MBG scaffolds significantly stimulate new bone formation in osteoporotic bone defects when compared to MBG scaffolds alone and Eu may be involved in the acceleration of bone regeneration in OVX rats. Our study for the first time reports that the incorporation of the rare earth element Eu into bioscaffolds has the ability to accelerate bone regeneration in vivo, and thus, the prepared Eu-MBG scaffolds possess bifunctional properties with biolabeling and bone regeneration.

Synthesis and investigation of a novel luminous hydrogel

An Eu-containing luminous hydrogel was synthesized by free radical copolymerization and ester hydrolysis. The hydrogel exhibits strong red fluorescence, excellent thermal stability and superhydrophilicity.

Europium-doped NaYF4 nanoparticles cause the necrosis of primary mouse bone marrow stromal cells through lysosome damage

Applications of europium-doped NaYF₄ (NaYF₄:Eu³⁺) nanoparticles in biomedical fields will inevitably increase their exposure to humans, therefore, the assessment of toxicities must be taken into consideration.

Bio-distribution and in vivo/in vitro toxicity profile of PEGylated polymer capsules encapsulating LaVO4:Tb3+ nanoparticles for bioimaging applications

Lanthanide-doped nanoparticles are being explored for bioimaging applications owing to their unique optical properties.

Europium as an inhibitor of Amyloid-β(1-42) induced membrane permeation

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Europium ions complex with GM1 gangliosides in phospholipid membranes.

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Europium ions cause inhibition Aβ–membrane interactions.

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Europium blocks an Aβ receptor protecting against membrane permeation.

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Discrete Aβ binding events correlate to specific membrane permeation events.

Soluble Amyloid-beta (Aβ) oligomers are a source of cytotoxicity in Alzheimer’s disease (AD). The toxicity of Aβ oligomers may arise from their ability to interact with and disrupt cellular membranes mediated by GM1 ganglioside receptors within these membranes. Therefore, inhibition of Aβ–membrane interactions could provide a means of preventing the toxicity associated with Aβ. Here, using Surface Plasmon field-enhanced Fluorescence Spectroscopy, we determine that the lanthanide, Europium III chloride (Eu³⁺), strongly binds to GM1 ganglioside-containing membranes and prevents the interaction with Aβ42 leading to a loss of the peptides ability to cause membrane permeation. Here we discuss the molecular mechanism by which Eu³⁺ inhibits Aβ42-membrane interactions and this may lead to protection of membrane integrity against Aβ42 induced toxicity.

Differential ERK activation during autophagy induced by europium hydroxide nanorods and trehalose: Maximum clearance of huntingtin aggregates through combined treatment

Accelerating the clearance of intracellular protein aggregates through elevation of autophagy represents a viable approach for the treatment of neurodegenerative diseases. In our earlier report, we have demonstrated the enhanced degradation of mutant huntingtin protein aggregates through autophagy process induced by europium hydroxide nanorods [EHNs: Eu(III)(OH)3], but the underlying molecular mechanism of EHNs mediated autophagy was unclear. The present report reveals that EHNs induced autophagy does not follow the classical AKT-mTOR and AMPK signaling pathways. The inhibition of ERK1/2 phosphorylation using the specific MEK inhibitor U0126 partially abrogates the autophagy as well as the clearance of mutant huntingtin protein aggregates mediated by EHNs suggesting that nanorods stimulate the activation of MEK/ERK1/2 signaling pathway during autophagy process. In contrast, another mTOR-independent autophagy inducer trehalose has been found to induce autophagy without activating ERK1/2 signaling pathway. Interestingly, the combined treatment of EHNs and trehalose leads to more degradation of mutant huntingtin protein aggregates than that obtained with single treatment of either nanorods or trehalose. Our results demonstrate the rational that further enhanced clearance of intracellular protein aggregates, needed for diverse neurodegenerative diseases, may be achieved through the combined treatment of two or more autophagy inducers, which stimulate autophagy through different signaling pathways.

DW-F5: A novel formulation against malignant melanoma from Wrightia tinctoria

Wrightia tinctoria is a constituent of several ayurvedic preparations against skin disorders including psoriasis and herpes, though not yet has been explored for anticancer potential. Herein, for the first time, we report the significant anticancer properties of a semi-purified fraction, DW-F5, from the dichloromethane extract of W. tinctoria leaves against malignant melanoma. DW-F5 exhibited anti-melanoma activities, preventing metastasis and angiogenesis in NOD-SCID mice, while being non-toxic in vivo. The major pathways in melanoma signaling mediated through BRAF, WNT/β-catenin and Akt-NF-κB converging in MITF-M, the master regulator of melanomagenesis, were inhibited by DW-F5, leading to complete abolition of MITF-M. Purification of DW-F5 led to the isolation of two cytotoxic components, one being tryptanthrin and the other being an unidentified aliphatic fraction. The overall study predicts Wrightia tinctoria as a candidate plant to be further explored for anticancer properties and DW-F5 as a forthcoming drug formulation to be evaluated as a chemotherapeutic agent against malignant melanoma.

Investigation of molecular mechanisms and regulatory pathways of pro-angiogenic nanorods

Angiogenesis, a process involving the growth of new blood vessels from the pre-existing vasculature, plays a crucial role in various pathophysiological conditions. We have previously demonstrated that europium hydroxide [Eu(III)(OH)3] nanorods (EHNs) exhibit pro-angiogenic properties through the generation of reactive oxygen species (ROS) and mitogen activated protein kinase (MAPK) activation. Considering the enormous implication of angiogenesis in cardiovascular diseases (CVDs) and cancer, it is essential to understand in-depth molecular mechanisms and signaling pathways in order to develop the most efficient and effective alternative treatment strategy for CVDs. However, the exact underlying mechanism and cascade signaling pathways behind the pro-angiogenic properties exhibited by EHNs still remain unclear. Herein, we report for the first time that the hydrogen peroxide (H2O2), a redox signaling molecule, generated by these EHNs activates the endothelial nitric oxide synthase (eNOS) that promotes the nitric oxide (NO) production in a PI3K (phosphoinositide 3-kinase)/Akt dependent manner, eventually triggering angiogenesis. We intensely believe that the investigation and understanding of the in-depth molecular mechanism and signaling pathways of EHNs induced angiogenesis will help us in developing an effective alternative treatment strategy for cardiovascular related and ischemic diseases where angiogenesis plays an important role.

Toxicological assessment of PEG functionalized f-block rare earth phosphate nanorods

Toxicological assessment of synthesized and PEG functionalized lanthanum phosphate nanorods.

In vivo biodistribution and toxicity of Gd2O3:Eu3+ nanotubes in mice after intraperitoneal injection

To better understand the potential impact of Gd₂O₃:Eu³⁺ nanotubes on human health, we investigated their biodistribution, subacute toxicity, and hepatic injury in mice under different dosages (4.0, 40.0, and 400.0 mg kg⁻¹).

Postoperative Hyperoxia (60%) Worsens Hepatic Injury in Mice

Background:

Liver damage by ischemia and reperfusion injury is a risk factor for morbidity and mortality after liver surgery. Postoperative oxygen treatment is routinely applied in the postanesthesia and intensive care unit after liver surgery. The risks of aggravating the injury by increasing inspiratory oxygen from 21 to 60% in the postoperative period were investigated in mice.

Methods:

Parameters of liver injury were compared after induction of hepatic ischemia–reperfusion injury, by clamping the left liver lobe for 45 min, and reperfusion for 24 h either under normoxic (21% oxygen) or hyperoxic (60% oxygen) conditions (n = 22 per group). The extent of tissue injury and oxidative responses was analyzed in the presence or absence of polymorphonuclear leukocytes, functional Kupffer cells, and the p47phox unit of the nicotinamide adenine dinucleotide phosphate oxidase (n = 6 to 11 per group).

Results:

Compared with postoperative normoxic conditions, hyperoxia increased cell damage (glutamate-pyruvate transaminase: 1,870 [±968 SD] vs. 60% 2,981 [±1,038 SD], 21 vs. 60% oxygen, in U/l as mean ± SD; P < 0.01), liver weights (341 ± 52 vs. 383 ± 44, 21 vs. 60% oxygen, in mg as mean ± SD; P = 0.02), damage scores (1.9 ± 0.8 vs. 3.1 ± 1.0, 21 vs. 60% oxygen, score as mean ± SD; P = 0.02), and reactive oxygen species (15.0 ± 12.0 vs. 30.4 ± 19.2, 21 vs. 60% oxygen, in μmol/l as mean ± SD; P < 0.05). The aggravation of the tissue damaging effects as a result of hyperoxia was not seen in mice with depletions of polymorphonuclear leukocytes or Kupffer cells, or with nonfunctioning nicotinamide adenine dinucleotide phosphate oxidase.

Conclusion:

Liver injury after ischemia was significantly aggravated by hyperoxia as a consequence of immune cell-mediated oxidative burst. Further studies are needed to elucidate whether routine delivery of high inspirational oxygen concentrations postoperatively should be limited.

Flavin containing monooxygenase 3 exerts broad effects on glucose and lipid metabolism and atherosclerosis

We performed silencing and overexpression studies of flavin containing monooxygenase (FMO) 3 in hyperlipidemic mouse models to examine its effects on trimethylamine N-oxide (TMAO) levels and atherosclerosis. Knockdown of hepatic FMO3 in LDL receptor knockout mice using an antisense oligonucleotide resulted in decreased circulating TMAO levels and atherosclerosis. Surprisingly, we also observed significant decreases in hepatic lipids and in levels of plasma lipids, ketone bodies, glucose, and insulin. FMO3 overexpression in transgenic mice, on the other hand, increased hepatic and plasma lipids. Global gene expression analyses suggested that these effects of FMO3 on lipogenesis and gluconeogenesis may be mediated through the PPARα and Kruppel-like factor 15 pathways. In vivo and in vitro results were consistent with the concept that the effects were mediated directly by FMO3 rather than trimethylamine/TMAO; in particular, overexpression of FMO3 in the human hepatoma cell line, Hep3B, resulted in significantly increased glucose secretion and lipogenesis. Our results indicate a major role for FMO3 in modulating glucose and lipid homeostasis in vivo, and they suggest that pharmacologic inhibition of FMO3 to reduce TMAO levels would be confounded by metabolic interactions.