Browse
Submit Data
Databases
API
Help

Dataset Information

25 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

BaGdF₅ Nanophosphors Doped with Different Concentrations of Eu³⁺ for Application in X-ray Photodynamic Therapy.

ABSTRACT: X-ray photodynamic therapy (XPDT) has been recently considered as an efficient alternative to conventional radiotherapy of malignant tissues. Nanocomposites for XPDT typically consist of two components-a nanophosphor which re-emits X-rays into visible light that in turn is absorbed by the second component, a photosensitizer, for further generation of reactive oxygen species. In this study, BaGdF₅ nanophosphors doped with different Eu:Gd ratios in the range from 0.01 to 0.50 were synthesized by the microwave route. According to transmission electron microscopy (TEM), the average size of nanophosphors was ~12 nm. Furthermore, different coatings with amorphous SiO₂ and citrates were systematically studied. Micro-CT imaging demonstrated superior X-ray attenuation and sufficient contrast in the liver and the spleen after intravenous injection of citric acid-coated nanoparticles. In case of the SiO₂ surface, post-treatment core-shell morphology was verified via TEM and the possibility of tunable shell size was reported. Nitrogen adsorption/desorption analysis revealed mesoporous SiO₂ formation characterized by the slit-shaped type of pores that should be accessible for methylene blue photosensitizer molecules. It was shown that SiO₂ coating subsequently facilitates methylene blue conjugation and results in the formation of the BaGdF₅: 10% Eu³⁺@SiO₂@MB nanocomposite as a promising candidate for application in XPDT.

SUBMITTER: Gadzhimagomedova Z

PROVIDER: S-EPMC8657490 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Tb-Doped core-shell-shell nanophosphors for enhanced X-ray induced luminescence and sensitization of radiodynamic therapy.

Project description:The development of radiation responsive materials, such as nanoscintillators, enables a variety of exciting new theranostic applications. In particular, the ability of nanophosphors to serve as molecular imaging agents in novel modalities, such as X-ray luminescence computed tomography (XLCT), has gained significant interest recently. Here, we present a radioluminescent nanoplatform consisting of Tb-doped nanophosphors with an unique core/shell/shell (CSS) architecture for improved optical emission under X-ray excitation. Owing to the spatial confinement and separation of luminescent activators, these CSS nanophosphors exhibited bright optical luminescence upon irradiation. In addition to standard physiochemical characterization, these CSS nanophosphors were evaluated for their ability to serve as energy mediators in X-ray stimulated photodynamic therapy, also known as radiodynamic therapy (RDT), through attachment of a photosensitizer, rose bengal (RB). Furthermore, cRGD peptide was used as a model targeting agent against U87 MG glioblastoma cells. In vitro RDT efficacy studies suggested the RGD-CSS-RB in combination with X-ray irradiation could induce enhanced DNA damage and increased cell killing, while the nanoparticles alone are well tolerated. These studies support the utility of CSS nanophosphors and warrants their further development for theranostic applications.

| S-EPMC7855282 | biostudies-literature

X-Ray Induced Photodynamic Therapy: A Combination of Radiotherapy and Photodynamic Therapy.

Project description:Conventional photodynamic therapy (PDT)'s clinical application is limited by depth of penetration by light. To address the issue, we have recently developed X-ray induced photodynamic therapy (X-PDT) which utilizes X-ray as an energy source to activate a PDT process. In addition to breaking the shallow tissue penetration dogma, our studies found more efficient tumor cell killing with X-PDT than with radiotherapy (RT) alone. The mechanisms behind the cytotoxicity, however, have not been elucidated. In the present study, we investigate the mechanisms of action of X-PDT on cancer cells. Our results demonstrate that X-PDT is more than just a PDT derivative but is essentially a PDT and RT combination. The two modalities target different cellular components (cell membrane and DNA, respectively), leading to enhanced therapy effects. As a result, X-PDT not only reduces short-term viability of cancer cells but also their clonogenecity in the long-run. From this perspective, X-PDT can also be viewed as a unique radiosensitizing method, and as such it affords clear advantages over RT in tumor therapy, especially for radioresistant cells. This is demonstrated not only in vitro but also in vivo with H1299 tumors that were either subcutaneously inoculated or implanted into the lung of mice. These findings and advances are of great importance to the developments of X-PDT as a novel treatment modality against cancer.

| S-EPMC5118595 | biostudies-literature

Application of Mitochondrially Targeted Nanoconstructs to Neoadjuvant X-ray-Induced Photodynamic Therapy for Rectal Cancer.

Project description:In this work, we brought together two existing clinical techniques used in cancer treatment-X-ray radiation and photodynamic therapy (PDT), whose combination termed X-PDT uniquely allows PDT to be therapeutically effective in deep tissue. To this end, we developed mitochondrially targeted biodegradable polymer poly(lactic-co-glycolic acid) nanocarriers incorporating a photosensitizer verteporfin, ultrasmall (2-5 nm) gold nanoparticles as radiation enhancers, and triphenylphosphonium acting as the mitochondrial targeting moiety. The average size of the nanocarriers was about 160 nm. Upon X-ray radiation our nanocarriers generated cytotoxic amounts of singlet oxygen within the mitochondria, triggering the loss of membrane potential and mitochondria-related apoptosis of cancer cells. Our X-PDT strategy effectively controlled tumor growth with only a fraction of radiotherapy dose (4 Gy) and improved the survival rate of a mouse model bearing colorectal cancer cells. In vivo data indicate that our X-PDT treatment is cytoreductive, antiproliferative, and profibrotic. The nanocarriers induce radiosensitization effectively, which makes it possible to amplify the effects of radiation. A radiation dose of 4 Gy combined with our nanocarriers allows equivalent control of tumor growth as 12 Gy of radiation, but with greatly reduced radiation side effects (significant weight loss and resultant death).

| S-EPMC7256935 | biostudies-literature

Red, Green, and Blue Photoluminescence of Ba₂SiO₄:M (M = Eu3+, Eu2+, Sr2+) Nanophosphors.

Project description:Divalent europium doped barium orthosilicate is a very important phosphor for the production of light emitting diodes (LEDs), generally associated to the green emission color of micron-sized crystals synthesized by means of solid-state reactions. This work presents the combustion synthesis as an energy and time-saving preparation method for very small nano-sized Ba₂SiO₄ particles, flexibly doped to acquire different emission energies. The size of the resulting spherical nanoparticles (NPs) of the green emitting Ba₂SiO₄:Eu2+ was estimated to about 35 nm applying the Scherrer equation and further characterized with aid of atomic force microscopy (AFM) as well as scanning electron microscopy (SEM). This phosphor is able to build homogeneous luminescent suspensions and was successfully down-sized without changing the optical properties in comparison to the bulk phosphors. Besides the X-ray diffraction (XRD) analysis and the different types of microscopy, the samples were characterized by luminescence spectroscopy. Undoped Ba₂SiO₄ NPs are not luminescent, but show characteristic red emission of the ⁵D₀ → ⁷FJ (J = 0-4) electronic transitions when doped with Eu3+ ions. Moreover, these orthosilicate nanoparticles generate blue light at low temperatures due to impurity-trapped excitons, introduced by the partial substitution of the Ba2+ with Sr2+ ions in the Ba₂SiO₄ lattice causing a substantial distortion. A model for the temperature behavior of the defect luminescence as well as for their nature is provided, based on temperature-dependent luminescence spectra and lifetime measurements.

| S-EPMC5521235 | biostudies-other

Application of Porphyrins in Antibacterial Photodynamic Therapy.

Project description:Antibiotics are commonly used to control, treat, or prevent bacterial infections, however bacterial resistance to all known classes of traditional antibiotics has greatly increased in the past years especially in hospitals rendering certain therapies ineffective. To limit this emerging public health problem, there is a need to develop non-incursive, non-toxic, and new antimicrobial techniques that act more effectively and quicker than the current antibiotics. One of these effective techniques is antibacterial photodynamic therapy (aPDT). This review focuses on the application of porphyrins in the photo-inactivation of bacteria. Mechanisms of bacterial resistance and some of the current 'greener' methods of synthesis of meso-phenyl porphyrins are discussed. In addition, significance and limitations of aPDT are also discussed. Furthermore, we also elaborate on the current clinical applications and the future perspectives and directions of this non-antibiotic therapeutic strategy in combating infectious diseases.

| S-EPMC6650910 | biostudies-literature

X-ray Activated Nanoplatforms for Deep Tissue Photodynamic Therapy.

Project description:Photodynamic therapy (PDT), the use of light to excite photosensitive molecules whose electronic relaxation drives the production of highly cytotoxic reactive oxygen species (ROS), has proven an effective means of oncotherapy. However, its application has been severely constrained to superficial tissues and those readily accessed either endoscopically or laparoscopically, due to the intrinsic scattering and absorption of photons by intervening tissues. Recent advances in the design of nanoparticle-based X-ray scintillators and photosensitizers have enabled hybridization of these moieties into single nanocomposite particles. These nanoplatforms, when irradiated with diagnostic doses and energies of X-rays, produce large quantities of ROS and permit, for the first time, non-invasive deep tissue PDT of tumors with few of the therapeutic limitations or side effects of conventional PDT. In this review we examine the underlying principles and evolution of PDT: from its initial and still dominant use of light-activated, small molecule photosensitizers that passively accumulate in tumors, to its latest development of X-ray-activated, scintillator-photosensitizer hybrid nanoplatforms that actively target cancer biomarkers. Challenges and potential remedies for the clinical translation of these hybrid nanoplatforms and X-ray PDT are also presented.

| S-EPMC9962876 | biostudies-literature

Lanthanide-doped bismuth-based nanophosphors for ratiometric upconversion optical thermometry.

Project description:Nanothermometry could realize stable, efficient, and noninvasive temperature detection at the nanoscale. Unfortunately, most applications of nanothermometers are still limited due to their intricate synthetic process and low-temperature sensitivity. Herein, we reported a kind of novel bismuth-based upconversion nanomaterial with a fast and facile preparation strategy. The bismuth-based upconversion luminophore was synthesized by the co-precipitation method within 1 minute. By optimizing the doping ratio of the sensitizer Yb ion and the activator Er ion and adjusting the synthetic solvent strategy, the crystallinity of the nanomaterials was increased and the upconversion luminescence intensity was improved. Ratiometric upconversion optical measurements of temperature in the range of 278 K to 358 K can be achieved by ratiometric characteristic emission peaks of thermally sensitive Er ion. This method of rapidly constructing nanometer temperature probes provides a feasible strategy for the construction of novel fluorescent temperature probes.

| S-EPMC8985227 | biostudies-literature

Enhanced Photodynamic Efficacy Using 1,8-Naphthalimides: Potential Application in Antibacterial Photodynamic Therapy.

Project description:This study addresses the need for antibacterial medication that can overcome the current problems of antibiotics. It does so by suggesting two 1,8-naphthalimides (NI1 and NI2) containing a pyridinium nucleus become attached to the imide-nitrogen atom via a methylene spacer. Those fluorescent derivatives are covalently bonded to the surface of a chloroacetyl-chloride-modified cotton fabric. The iodometric method was used to study the generation of singlet oxygen (1O2) by irradiation of KI in the presence of monomeric 1,8-naphthalimides and the dyed textile material. Both compounds generated reactive singlet oxygen, and their activity was preserved even after they were deposited onto the cotton fabric. The antibacterial activity of NI1 and NI2 in solution and after their covalent bonding to the cotton fabric was investigated. In vitro tests were performed against the model gram-positive bacteria B. cereus and gram-negative P. aeruginosa bacteria in dark and under light iradiation. Compound NI2 showed higher antibacterial activity than compound NI1. The light irradiation enhanced the antimicrobial activity of the compounds, with a better effect achieved against B. cereus.

| S-EPMC9504615 | biostudies-literature

Carbon-Doped TiO2 Activated by X-Ray Irradiation for the Generation of Reactive Oxygen Species to Enhance Photodynamic Therapy in Tumor Treatment.

Project description:Traditional photodynamic therapy (PDT) is limited by the penetration depth of visible light. Although the light source has been changed to near infrared, infrared light is unable to overcome the penetration barrier and it is only effective at the surface of the tumors. In this study, we used X-ray as a light source for deep-seated tumor treatment. A particle with a narrow band gap when exposed to soft X-rays would produce reactive oxygen species (ROS) to kill tumor cell, with less damage to the normal tissues. Anatase TiO2 has been studied as a photosensitizer in PDT. In the experiment, C was doped into the anatase lattice at an optimum atomic ratio to make the band gap narrower, which would be activated by X-ray to produce more ROS and kill tumor cells under stress. The results showed that the synthesized TiO2:C particles were identified as crystal structures of anatase. The synthesized particles could be activated effectively by soft X-rays to produce ROS, to degrade methylene blue by up to 30.4%. Once TiO2:C was activated by X-ray irradiation, the death rate of A549 cells in in vitro testing was as high as 16.57%, on day 2. In the animal study, the tumor size gradually decreased after treatment with TiO2:C and exposure to X-rays on day 0 and day 8. On day 14, the tumor declined to nearly half of its initial volume, while the tumor in the control group was twice its initial volume. After the animal was sacrificed, blood, and major organs were harvested for further analysis and examination, with data fully supporting the safety of the treatment. Based on the results of the study, we believe that TiO2:C when exposed to X-rays could overcome the limitation of penetration depth and could improve PDT effects by inhibiting tumor growth effectively and safely, in vivo.

| S-EPMC6540153 | biostudies-literature

Dipyrrinato-Iridium(III) Complexes for Application in Photodynamic Therapy and Antimicrobial Photodynamic Inactivation.

Project description:The generation of bio-targetable photosensitizers is of utmost importance to the emerging field of photodynamic therapy and antimicrobial (photo-)therapy. A synthetic strategy is presented in which chelating dipyrrin moieties are used to enhance the known photoactivity of iridium(III) metal complexes. Formed complexes can thus be functionalized in a facile manner with a range of targeting groups at their chemically active reaction sites. Dipyrrins with N- and O-substituents afforded (dipy)iridium(III) complexes via complexation with the respective Cp*-iridium(III) and ppy-iridium(III) precursors (dipy=dipyrrinato, Cp*=pentamethyl-η5 -cyclopentadienyl, ppy=2-phenylpyridyl). Similarly, electron-deficient [IrIII (dipy)(ppy)2 ] complexes could be used for post-functionalization, forming alkenyl, alkynyl and glyco-appended iridium(III) complexes. The phototoxic activity of these complexes has been assessed in cellular and bacterial assays with and without light; the [IrIII (Cl)(Cp*)(dipy)] complexes and the glyco-substituted iridium(III) complexes showing particular promise as photomedicine candidates. Representative crystal structures of the complexes are also presented.

| S-EPMC8248005 | biostudies-literature