Synthesis of Y2O3: Eu Luminescent Phosphor with Increased Dispersion for Use in Medical Purposes

2021 ◽  
Vol 1040 ◽  
pp. 61-67
Author(s):  
Anna B. Vlasenko ◽  
Vadim V. Bakhmetyev ◽  
Sergey V. Mjakin
Keyword(s):  
Particle Size ◽  
Photodynamic Therapy ◽  
Visible Light ◽  
Modern Method ◽  
The Body ◽  
Hydrothermal Processing ◽  
X Ray ◽  
Microwave Annealing ◽  
Body Tissues ◽  
Pyrogenic Silica

Photodynamic therapy (PDT) is a promising modern method for treatment of oncological, bacterial, fungal and viral diseases. However, its application is limited to diseases with superficial localization since the body tissues are not transparent for visible light. To address this problem and extend PDT application to abdominal diseases, an enhanced method of X-ray photodynamic therapy (XRPDT) is suggested, involving X-ray radiation easily penetrating the body tissues. The implementation of this approach requires the development of a pharmacological drug including a photosensitizer stimulated by visible light to yield active oxygen and a nanosized phosphor converting X-ray radiation into visible light with the wavelength required for the photosensitizer activation. This study is aimed at obtaining X-ray stimulated phosphors with nanosized particles suitable for XRPDT application. For this purpose, Y2O3:Eu phosphors were synthesized via hydrothermal processing of the corresponding mixed acetate followed by annealing. To prevent from the undesirable agglomeration of the particles in the course of hydrothermal synthesis and subsequent annealing, different techniques were used, including rapid thermal annealing (RTA), microwave annealing and addition of finely dispersed pyrogenic silica (aerosil) to the phosphor. The microwave annealing was carried out using a special installation including a resonance chamber for maintaining a standing wave of microwave radiation. The performed research allowed the determination of hydrothermal processing optimal duration affording the synthesis of phosphors with the highest luminescence brightness. The application of microwave annealing is found to provide phosphors with a more perfect crystal structure compared with RTA. The developed method of Y2O3:Eu phosphor synthesis involving pyrogenic silica addition to the autoclave allowed the preparation of samples with the amorphous structure and significantly reduced the particle size without a considerable decrease in the luminescence brightness. The particle size of the phosphor synthesized with aerosil addition is less than 100 nm that allows its implementation in pharmacological drugs for XRPDT.

scholarly journals X-ray induced photodynamic therapy with copper-cysteamine nanoparticles in mice tumors

2019 ◽  
Vol 116 (34) ◽  
pp. 16823-16828 ◽  
Author(s):  
Samana Shrestha ◽  
Jing Wu ◽  
Bindeshwar Sah ◽  
Adam Vanasse ◽  
Leon N Cooper ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Treatment Method ◽  
The Body ◽  
Target Cells ◽  
X Rays ◽  
X Ray ◽  
Mouse Tumors ◽  
Study Results ◽  
New Type

Photodynamic therapy (PDT), a treatment that uses a photosensitizer, molecular oxygen, and light to kill target cells, is a promising cancer treatment method. However, a limitation of PDT is its dependence on light that is not highly penetrating, precluding the treatment of tumors located deep in the body. Copper-cysteamine nanoparticles are a new type of photosensitizer that can generate cytotoxic singlet oxygen molecules upon activation by X-rays. In this paper, we report on the use of copper-cysteamine nanoparticles, designed to be targeted to tumors, for X-ray–induced PDT. In an in vivo study, results show a statistically significant reduction in tumor size under X-ray activation of pH-low insertion peptide–conjugated, copper-cysteamine nanoparticles in mouse tumors. This work confirms the effectiveness of copper-cysteamine nanoparticles as a photosensitizer when activated by radiation and suggests that these Cu-Cy nanoparticles may be good candidates for PDT in deeply seated tumors when combined with X-rays and conjugated to a tumor-targeting molecule.

A Comparative Study on the Role of Precursors of Graphitic Carbon Nitrides for the Photocatalytic Degradation of Direct Red 81

2014 ◽  
Vol 807 ◽  
pp. 101-113 ◽  
Author(s):  
J. Theerthagiri ◽  
R.A. Senthil ◽  
J. Madhavan ◽  
B. Neppolian
Keyword(s):  
Particle Size ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Visible Light Irradiation ◽  
Carbon Nitride ◽  
Light Irradiation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carbon Nitrides

The graphitic carbon nitride (g-C3N4) materials have been synthesized from nitrogen rich precursors such as urea and thiourea by directly heating at 520 °C for 2 h. The as-synthesized carbon nitride samples were characterized by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible (UV-vis) absorption spectroscopy, photoluminescence (PL) and particle size analysis. The photoelectrochemical measurements were performed using several on-off cycles under visible-light irradiation. The x-ray diffraction peak is broader which indicates the fine powder nature of the synthesized materials. The estimated crystallite size of carbon nitrides synthesized from urea (U-CN) and thiourea (T-CN) are 4.0 and 4.4 nm respectively. The particle size of U-CN and T-CN were analysed by particle size analyser and were found to be 57.3 and 273.3 nm respectively. The photocatalytic activity for the degradation of the textile dye namely, direct red-81 (DR81) using these carbon nitrides were carried out under visible light irradiation. In the present investigation, a comparison study on the carbon nitrides synthesized from cheap precursors such as urea and thiourea for the degradation of DR81 has been carried out. The results inferred that U-CN exhibited higher photocatalytic activity than T-CN. The photoelectrochemical studies confirmed that the (e--h+) charge carrier separation is more efficient in U-CN than that of T-CN and therefore showed high photocatalytic degradation. Further, the smaller particle size of U-CN is also responsible for the observed degradation trend.

scholarly journals The Rare-Earth Elements Doping of BaGdF5 Nanophosphors for X-ray Photodynamic Therapy

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3212
Author(s):  
Daria Kirsanova ◽  
Vladimir Polyakov ◽  
Vera Butova ◽  
Peter Zolotukhin ◽  
Anna Belanova ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Photodynamic Therapy ◽  
Rare Earth ◽  
Reactive Oxygen Species Generation ◽  
The Body ◽  
Oxygen Species ◽  
X Rays ◽  
X Ray ◽  
Optical Luminescence ◽  
Luminescence Characteristics

It is known that the initiation of photodynamic therapy (PDT) in deep-seated tumors requires the use of X-rays to activate the reactive oxygen species generation in deep tissues. The aim of this paper is to synthesize X-ray nanophosphors and analyze their structural and luminescence characteristics to push the PDT process deep into the body. The article deals with BaGdF5:Eu3+, BaGdF5:Sm3+, and BaGdF5:Tb3+ nanophosphors synthesized using microwave synthesis. It is found that the nanoparticles are biocompatible and have sizes 5–17 nm. However, according to the analysis of X-ray excited optical luminescence, BaGdF5:Sm3+ nanophosphors will not be effective for treating deep-seated tumors. Thus, BaGdF5:Eu3+ and BaGdF5:Tb3+ nanoparticles meet the requirements for the subsequent production of nanocomposites based on them that can be used in X-ray photodynamic therapy.

scholarly journals Synthesis of rare-earth nanosized phosphors using microwave processing

2021 ◽  
Vol 2056 (1) ◽  
pp. 012049
Author(s):  
A B Vlasenko ◽  
V V Bakhmetyev
Keyword(s):  
Particle Size ◽  
Hydrothermal Synthesis ◽  
Visible Light ◽  
Average Particle Size ◽  
Microwave Treatment ◽  
Viral Diseases ◽  
Medical Applications ◽  
Average Particle ◽  
Light Spectrum ◽  
X Ray

Abstract Nanomaterials find permanently extending applications in various areas of life. In particular, nanosized phosphors can be used as pharmaceutical carriers capable of emitting ultraviolet or visible light that activates a photosensitizer, thus significantly expanding the possibilities of photodynamic therapy in the treatment of oncological, bacterial and viral diseases. The conditions required for the use of nanosized phosphors in medicine include their fine dispersion and effective luminescence in the red region of visible light spectrum upon stimulation by X-ray radiation of the range accepted for medical applications, particularly for diagnostic and therapeutic purposes in many diseases. The aim of this work was to study the effect of microwave treatment of Y2O3:Eu phosphors prepared by hydrothermal synthesis in ethylene glycol at 230 °C for 6 hours, involving the decomposition of mixed acetate. In order to reduce the aggregation and growth of the resulting particles, Aerosil A300 with average particle size 7 nm was added to the reaction mixture in the course of hydrothermal synthesis in the ratio 1:1 relating to the obtained phosphor. The microwave treatment was carried out at 800 °C for 5 minutes. The developed method provided Y2O3:Eu phosphor samples featuring with increased luminescence intensity in the region 610…700 nm compared to similar phosphors earlier prepared using the rapid thermal annealing (RTA) procedure.

scholarly journals Structure of Hard And Soft Carapace Exoskeleton Biomaterial Through SEM-EDXRS at Various Stages of Development Scylla paramamosain Mud Crab

2021 ◽  
Vol 15 ◽  
pp. 113-122
Author(s):  
Haryo Triajie ◽  
Sri Andayani ◽  
Uun Yanuhar ◽  
Arning Wilujeng Ekawati
Keyword(s):  
Point Of View ◽  
The Body ◽  
Scylla Paramamosain ◽  
Inorganic Elements ◽  
Mud Crab ◽  
Stages Of Development ◽  
X Ray ◽  
Body Tissues ◽  
Mangrove Crabs ◽  
Scanning Electron

Crustacean carapace has various functions which can be seen from the composition of the biomaterial in it. Various concentrations of inorganic biomaterial elements were investigated from the hard carapace and the newly molted (soft-shelled) (Scylla paramamosain) with SEM-EDXRS (scanning electron microscopy-Energy Dispersive X-ray Spectrometer) technique. This study traced the composition of the inorganic elements of the premolt, postmolt, intermolt and soft (exuvium) crab hard carapace tissue of mangrove crabs from the point of view. Various stages of development. Important elements such as C, O2, Mg, P, Ca, S, Na, Si, Cl, and others, are reabsorbed from the carapace into the body tissues to fulfill further needs in soft-shelled crabs and are reused to some extent during formation new carapace. This study provides evidence that, inorganic elements in freshly molted soft carapace crabs are less common than hard carapace crabs

Synthesis of Y2O3: Eu Nanosized Phosphor Using Hydrothermal Technique and Rapid Thermal Annealing (RTA)

2020 ◽  
Vol 854 ◽  
pp. 209-215
Author(s):  
Anna B. Vlasenko ◽  
Vadim V. Bakhmetyev
Keyword(s):  
Particle Size ◽  
Hydrothermal Synthesis ◽  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
The Body ◽  
Γ Radiation ◽  
Abdominal Tumors ◽  
Body Tissues ◽  
Synthetic Approaches ◽  
Synthesis Duration

The application of special nanomaterials is promising for the development of new methods for the diagnostics and treatment of cancer. Photodynamic therapy (PDT) is a well-known and recognized method of cancer treatment. This type of therapy is less carcinogenic and mutagenic compared to radiation and chemotherapy, since the applied photosensitizers do not bind to DNA of the cells. However, currently this technique is only applicable to skin cancer, while its extension to the treatment of abdominal tumors requires the creation of pharmacological drugs for PDT, which along with a photosensitizer include a colloidal solution of nanosized luminescent phosphor emitting visible light with the required wavelength under the influence of infrared, X-ray or γ-radiation, which easily penetrates the body tissues. Since photosensitizers are already available as commercial products, the most important goal is the development of nanosized phosphors providing the required radiation convertion. In this study, the effects of hydrothermal synthesis, duration and the conditions of rapid thermal annealing (RTA) on Y2O3:Eu phosphor particle size were studied. The hydrothermal synthesis technique was carried out in two ways: chloride (precipitation from a chloride solution using NaOH and NH4OH precipitators) and acetate (decomposition of mixed acetate either without a dispersant at 230° C for 24 hours, or using PEG-200 and PEG-2000 as dispersants at 230 °C for 12 hours). The rapid thermal annealing was performed either at 600 °C for 20 minutes, or at 800 °C for 5 minutes. The developed synthetic approaches afforded Y2O3:Eu nanosized phosphor samples with the particle size not exceeding 200 nm.

Preparation and characterization of anatase N–F-codoped TiO2 sol and its photocatalytic degradation for formaldehyde

2007 ◽  
Vol 22 (9) ◽  
pp. 2389-2397 ◽  
Author(s):  
Donggen Huang ◽  
Shijun Liao ◽  
Shuiqing Quan ◽  
Lei Liu ◽  
Zongjian He ◽  
...  
Keyword(s):  
Particle Size ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Average Particle Size ◽  
Synergetic Effect ◽  
Tetrabutyl Titanate ◽  
Average Particle ◽  
Dielectric Relaxation Spectroscopy ◽  
X Ray

Anatase nitrogen and fluoride codoped TiO2 sol (N–F–TiO2) catalysts were fabricated by a modified sol-gel hydrothermal method, using tetrabutyl titanate as precursor. The microstructure and morphology of sol sample were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet-visible dielectric relaxation spectroscopy (UV-VIS-DRS), x-ray photoelectron spectroscopy (XPS), etc. It was shown that N–F–TiO2 particles in sol were partly crystallized to anatase structure and dispersed in the aqueous medium homogeneously. The average particle size was ∼12.0 nm calculated from XRD patterns, and the particle size distribution was narrow. It was noteworthy that the N–F-codoped TiO2 sol particles showed strong visible-light response and high photocatalytic activity for formaldehyde degradation under irradiation by visible light (400–500 nm); we suggested that it may result from the generation of additional band of N 2p in the forbidden band and the synergetic effect of codoping nitrogen and fluorine.

Using Voxel Count Measurements Based On X-Ray Attenuation Coefficient Principle to Estimate Organ Volume during CT Scan

2017 ◽  
pp. 653-659
Author(s):  
Issahaku Shirazu ◽  
Y. B Mensah ◽  
Cyril Schandorf ◽  
S. Y. Mensah
Keyword(s):  
Attenuation Coefficient ◽  
The Body ◽  
Linear Attenuation Coefficient ◽  
X Rays ◽  
Simple Method ◽  
Attenuation Coefficients ◽  
X Ray ◽  
Organ Volume ◽  
Count Method ◽  
Body Tissues

The study provided a simple method of using voxel count method to estimate organ volume together with x-ray attenuation coefficient principle. The aim is to discuss the role of x-ray attenuation coefficient in CT organ volume measurements using voxel count method. The method involve using the principle of linear attenuation coefficient which describes the fraction of a beam of x-rays or gamma rays that is absorbed or scattered per unit thickness of the absorber to enable tissue differentiation and hence the used of volume elements method, where the body is literally divided into 3-dimensional rectangular boxes with known size and thickness. This value basically accounts for the number of atoms within a specified distance of a material and the probability of a photon being scattered or absorbed from the nucleus or an electron of one of these atoms. A graph of linear attenuation coefficients versus radiation energy are used to separate between various body tissues. At a specific energy the difference in attenuation between two tissues is greatest at a specific radiographic contrast in an image. Hence, this variation enable a separation and subsequent measurements of varied tissues. Therefore, it is extremely useful to determine various linear attenuation coefficients of tissues to enable various variations to be determine for clinical application.

scholarly journals Nanomaterials for Enhanced Photodynamic Therapy

2020 ◽  
Author(s):  
Lucas F. de Freitas
Keyword(s):  
Photodynamic Therapy ◽  
Visible Light ◽  
Tumor Targeting ◽  
Oxygen Supply ◽  
Cherenkov Radiation ◽  
Invasive Procedure ◽  
Full Potential ◽  
X Ray ◽  
Non Invasive ◽  
Clinical Potential

Photodynamic therapy is a non-invasive option for eliminating superficial tumors and to control infections. However, despite some protocols are already approved for the clinic, PDT applications could be much broader if some of its main hindrances were overcome. For instance, the most efficient photosensitizers are hydrophobic, so if one injects them intravenously they tend to aggregate and to be internalized by phagocytes in the blood, impairing the delivery to the target site. In addition, visible light has a limited penetration in tissues, therefore the main applications of PDT are limited to superficial tumors unless an invasive procedure is used for the light to reach deeper sites. Another setback is the hypoxia that commonly happens in tumors, hindering the full potential of PDT as it depends on a constant oxygen supply. In this chapter the reader will find some strategies based on Nanotechnology to overcome these and other obstacles for PDT to reach its full clinical potential, i.e. hypoxia-reverting protocols, X-ray-driven PDT, Cherenkov radiation-driven PDT, and active tumor-targeting.

X-ray micro tomography in the scanning electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 106-107 ◽  
Author(s):  
W. Brünger
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Target Surface ◽  
The Body ◽  
X Rays ◽  
Cross Sectional ◽  
X Ray ◽  
Micro Tomography ◽  
Scanning Electron

Reconstructive tomography is a new technique in diagnostic radiology for imaging cross-sectional planes of the human body /1/. A collimated beam of X-rays is scanned through a thin slice of the body and the transmitted intensity is recorded by a detector giving a linear shadow graph or projection (see fig. 1). Many of these projections at different angles are used to reconstruct the body-layer, usually with the aid of a computer. The picture element size of present tomographic scanners is approximately 1.1 mm2.Micro tomography can be realized using the very fine X-ray source generated by the focused electron beam of a scanning electron microscope (see fig. 2). The translation of the X-ray source is done by a line scan of the electron beam on a polished target surface /2/. Projections at different angles are produced by rotating the object.During the registration of a single scan the electron beam is deflected in one direction only, while both deflections are operating in the display tube.

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