1
|
Liu YS, Wei X, Zhao X, Chen LJ, Yan XP. Near-Infrared Photothermal/Photodynamic-in-One Agents Integrated with a Guanidinium-Based Covalent Organic Framework for Intelligent Targeted Imaging-Guided Precision Chemo/PTT/PDT Sterilization. ACS Appl Mater Interfaces 2021; 13:27895-27903. [PMID: 34101418 DOI: 10.1021/acsami.1c05705] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Phototherapy holds great promise in the treatment of bacterial infections, especially the multidrug resistant bacterial infections. However, most therapeutic agents are based on the integration of individual photothermal agents and photosensitizers, always in the activated state, and generally lack bacterial specificity, resulting in uncertain pharmacokinetics and serious nonspecific damage to normal tissues. Herein, we report a pH-responsive nanoplatform with synergistic chemo-phototherapy function for smart fluorescence imaging-guided precision sterilization. pH reversible activated symmetric cyanine was designed and prepared as a bacterial-specific imaging unit and PTT/PDT-in-one agent. Meanwhile, a guanidinium-based covalent organic framework (COF) was employed as a nanocarrier and chemotherapy agent to build the intelligent nanoplatform via electrostatic self-assembly. The self-assembly of the PTT/PDT-in-one agent and the COF greatly improves the stability and blood circulation of the PTT/PDT-in-one agent and provides charge-reversed intelligent targeting ability. The developed smart nanoplatform not only enables bacterial-targeted imaging but also possesses chemo/PTT/PDT synergetic high-efficiency bactericidal effects with little side effects, showing great potential in practical applications.
Collapse
Affiliation(s)
- Yu-Shi Liu
- Institute of Analytical Food Safety, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Xiang Wei
- Institute of Analytical Food Safety, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Xu Zhao
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China
- Institute of Analytical Food Safety, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Li-Jian Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China
- Institute of Analytical Food Safety, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Xiu-Ping Yan
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China
- Institute of Analytical Food Safety, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China
| |
Collapse
|
2
|
Du Y, Sun H, Lux F, Xie Y, Du L, Xu C, Zhang H, He N, Wang J, Liu Y, Leduc G, Doussineau T, Ji K, Wang Q, Lin Z, Wang Y, Liu Q, Tillement O. Radiosensitization Effect of AGuIX, a Gadolinium-Based Nanoparticle, in Nonsmall Cell Lung Cancer. ACS Appl Mater Interfaces 2020; 12:56874-56885. [PMID: 33326207 DOI: 10.1021/acsami.0c16548] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Radiotherapy is the main treatment for cancer patients. A major concern in radiotherapy is the radiation resistance of some tumors, such as human nonsmall cell lung cancer. However, the radiation dose delivered to the tumors is often limited by the possibility of collateral damage to surrounding healthy tissues. A new and efficient gadolinium-based nanoparticle, AGuIX, has recently been developed for magnetic resonance imaging-guided radiotherapy and has been proven to act as an efficient radiosensitizer. The amplified radiation effects of AGuIX nanoparticles appear to be due to the emission of low-energy photoelectrons and Auger electron interactions. We demonstrated that AGuIX nanoparticles exacerbated radiation-induced DNA double-strand break damage and reduced DNA repair in the H1299 nonsmall cell lung cancer cell line. Furthermore, we observed a significant improvement in tumor cell damage and growth suppression, under radiation therapy, with the AGuIX nanoparticles in a H1299 mouse xenograft model. This study paves the way for research into the radiosensitization mechanism of AGuIX nanoparticles and provides a scientific basis for the use of AGuIX nanoparticles as radiosensitizing drugs.
Collapse
Affiliation(s)
- Yanan Du
- Institute of Radiation Medicine& Peking Union Medical College, Chinese Academy of Medical Sciences, 300192 Tianjin, China
- Tianjin Center for Disease Control and Prevention, 300011 Tianjin, China
| | - Hao Sun
- Institute of Radiation Medicine& Peking Union Medical College, Chinese Academy of Medical Sciences, 300192 Tianjin, China
| | - François Lux
- Institute Light and Mater, UMR5306, Lyon1 University-CNRS, Lyon University, 69100 Villeurbanne, France
- NH TherAguix, NH TherAguix SAS, 69100 Villeurbanne, France
| | - Yi Xie
- Institute of Modern Physics, Chinese Academy of Sciences, 730000 Lanzhou, China
| | - Liqing Du
- Institute of Radiation Medicine& Peking Union Medical College, Chinese Academy of Medical Sciences, 300192 Tianjin, China
| | - Chang Xu
- Institute of Radiation Medicine& Peking Union Medical College, Chinese Academy of Medical Sciences, 300192 Tianjin, China
| | - Hong Zhang
- Institute of Modern Physics, Chinese Academy of Sciences, 730000 Lanzhou, China
| | - Ningning He
- Institute of Radiation Medicine& Peking Union Medical College, Chinese Academy of Medical Sciences, 300192 Tianjin, China
| | - Jinhan Wang
- Institute of Radiation Medicine& Peking Union Medical College, Chinese Academy of Medical Sciences, 300192 Tianjin, China
| | - Yang Liu
- Institute of Radiation Medicine& Peking Union Medical College, Chinese Academy of Medical Sciences, 300192 Tianjin, China
| | | | | | - Kaihua Ji
- Institute of Radiation Medicine& Peking Union Medical College, Chinese Academy of Medical Sciences, 300192 Tianjin, China
| | - Qin Wang
- Institute of Radiation Medicine& Peking Union Medical College, Chinese Academy of Medical Sciences, 300192 Tianjin, China
| | - Zhenhua Lin
- NH TherAguix, NH TherAguix SAS, 69100 Villeurbanne, France
| | - Yan Wang
- Institute of Radiation Medicine& Peking Union Medical College, Chinese Academy of Medical Sciences, 300192 Tianjin, China
| | - Qiang Liu
- Institute of Radiation Medicine& Peking Union Medical College, Chinese Academy of Medical Sciences, 300192 Tianjin, China
| | - Olivier Tillement
- Institute Light and Mater, UMR5306, Lyon1 University-CNRS, Lyon University, 69100 Villeurbanne, France
- NH TherAguix, NH TherAguix SAS, 69100 Villeurbanne, France
| |
Collapse
|
3
|
Gao C, Kwong CHT, Sun C, Li Z, Lu S, Yang YW, Lee SMY, Wang R. Selective Decoating-Induced Activation of Supramolecularly Coated Toxic Nanoparticles for Multiple Applications. ACS Appl Mater Interfaces 2020; 12:25604-25615. [PMID: 32406668 DOI: 10.1021/acsami.0c05013] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In spite of the rapid emergence of numerous nanoparticles (NPs) for biomedical applications, it is often challenging to precisely control, or effectively tame, the bioactivity/toxicity of NPs, thereby exhibiting limited applications in biomedical areas. Herein, we report the construction of hyaluronic acid (HA)-laminated, otherwise toxic methylviologen (MV), NPs via ternary host-guest complexation among cucurbit[8]uril, trans-azobenzene-conjugated HA, and MV-functionalized polylactic acid NPs (MV-NPs). The high, nonspecific toxicity of MV-NPs was effectively shielded (turned off) by HA lamination, as demonstrated in cells, zebrafish, and mouse models. The supramolecular host-guest interaction-mediated HA coating offered several HA-MV-NP modalities, including hyaluronidase locally and photoirradiation remotely, to precisely remove HA lamination on demand, thereby endowing materials with the capability of selective decoating-induced activation (DIA) for applications as a user-friendly herbicide, a selective antibacterial agent, or an anticancer nanomedicine. This work offers facile supramolecular coating and DIA strategies to effectively tame and precisely control the bioactivity and toxicity of functional nanomaterials for diverse applications.
Collapse
Affiliation(s)
- Cheng Gao
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Taipa, Macao 999078, China
| | - Cheryl H T Kwong
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Taipa, Macao 999078, China
| | - Chen Sun
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Taipa, Macao 999078, China
| | - Zheng Li
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, International Joint Research Laboratory of Nano-Micro Architecture Chemistry (NMAC), College of Chemistry, Jilin University, Changchun 130012, China
| | - Siyu Lu
- Green Catalysis Center, College of Chemistry, Zhengzhou University, 100 Kexue Road, Zhengzhou 450001, China
| | - Ying-Wei Yang
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, International Joint Research Laboratory of Nano-Micro Architecture Chemistry (NMAC), College of Chemistry, Jilin University, Changchun 130012, China
| | - Simon M Y Lee
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Taipa, Macao 999078, China
| | - Ruibing Wang
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Taipa, Macao 999078, China
| |
Collapse
|
4
|
Wang Q, Ji Y, Shi J, Wang L. NIR-Driven Water Splitting H 2 Production Nanoplatform for H 2-Mediated Cascade-Amplifying Synergetic Cancer Therapy. ACS Appl Mater Interfaces 2020; 12:23677-23688. [PMID: 32380825 DOI: 10.1021/acsami.0c03852] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
As a newly emerging treatment strategy for many diseases, hydrogen therapy has attracted a lot of attention because of its excellent biosafety. However, the high diffusivity and low solubility of hydrogen make it difficult to accumulate in local lesions. Herein, we develop a H2 self-generation nanoplatform by in situ water splitting driven by near-infrared (NIR) laser. In this work, core-shell nanoparticles (CSNPs) of NaGdF4:Yb,Tm/g-C3N4/Cu3P (UCC) nanocomposites as core encapsulated with zeolitic imidazolate framework-8 (ZIF-8) modified with folic acid as shell are designed and synthesized. Due to the acid-responsive ZIF-8 shell, enhanced permeability and retention (EPR) effect, and folate receptor-mediated endocytosis, CSNPs are selectively captured by tumor cells. Upon 980 nm laser irradiation, CSNPs exhibit a high production capacity of H2 and active oxygen species (ROS), as well as an appropriate photothermal conversion temperature. Furthermore, rising temperature increases the Fenton reaction rate of Cu(I) with H2O2 and strengthens the curative effect of chemodynamic therapy (CDT). The excess glutathione (GSH) in tumor microenvironment (TME) can deplete positive holes produced in the valence band of g-C3N4 in the g-C3N4/Cu3P Z-scheme heterojunction. GSH also can reduce Cu(II) to Cu(I), ensuring a continuous Fenton reaction. Thus, a NIR-driven H2 production nanoplatform is constructed for H2-mediated cascade-amplifying multimodal synergetic therapy.
Collapse
Affiliation(s)
- Qi Wang
- College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao 266109, China
| | - Yishun Ji
- Department of Thyroid and Breast Surgery, Chengyang People's Hospital, Qingdao 266109, China
| | - Jinsheng Shi
- College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao 266109, China
| | - Lili Wang
- Science and Information College, Qingdao Agricultural University, Qingdao 266109, China
| |
Collapse
|
5
|
El Rouby WMA, Farghali AA, Hamdedein A. Microwave synthesis of pure and doped cerium (IV) oxide (CeO 2) nanoparticles for methylene blue degradation. Water Sci Technol 2016; 74:2325-2336. [PMID: 27858789 DOI: 10.2166/wst.2016.420] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Cerium (IV) oxide (CeO2), samarium (Sm) and gadolinium (Gd) doped CeO2 nanoparticles were prepared using microwave technique. The effect of microwave irradiation time, microwave power and pH of the starting solution on the structure and crystallite size were investigated. The prepared nanoparticles were characterized using X-ray diffraction, FT-Raman spectroscopy, and transmission electron microscope. The photocatalytic activity of the as-prepared CeO2, Sm and Gd doped CeO2 toward degradation of methylene blue (MB) dye was investigated under UV light irradiation. The effect of pH, the amount of catalyst and the dye concentration on the degradation extent were studied. The photocatalytic activity of CeO2 was kinetically enhanced by trivalent cation (Gd and Sm) doping. The results revealed that Gd doped CeO2 nanoparticles exhibit the best catalytic degradation activity on MB under UV irradiation. For clarifying the environmental safety of the by products produced from the degradation process, the pathways of MB degradation were followed using liquid chromatography/mass spectroscopy (LC/MS). The total organic carbon content measurements confirmed the results obtained by LC/MS. Compared to the same nanoparticles prepared by another method, it was found that Gd doped CeO2 prepared by hydrothermal process was able to mineralize MB dye completely under UV light irradiation.
Collapse
Affiliation(s)
- W M A El Rouby
- Materials Science and Nanotechnology Department, Faculty of Postgraduate Studies for Advanced Science (PSAS), Beni-Suef University, Beni-Suef, Egypt E-mail:
| | - A A Farghali
- Materials Science and Nanotechnology Department, Faculty of Postgraduate Studies for Advanced Science (PSAS), Beni-Suef University, Beni-Suef, Egypt E-mail:
| | - A Hamdedein
- Materials Science and Nanotechnology Department, Faculty of Postgraduate Studies for Advanced Science (PSAS), Beni-Suef University, Beni-Suef, Egypt E-mail:
| |
Collapse
|
6
|
Birka M, Roscher J, Holtkamp M, Sperling M, Karst U. Investigating the stability of gadolinium based contrast agents towards UV radiation. Water Res 2016; 91:244-50. [PMID: 26802476 DOI: 10.1016/j.watres.2016.01.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 01/05/2016] [Accepted: 01/08/2016] [Indexed: 05/28/2023]
Abstract
Since the 1980s, the broad application of gadolinium(Gd)-based contrast agents for magnetic resonance imaging (MRI) has led to significantly increased concentrations of Gd in the aqueous environment. Little is known about the stability of these highly polar xenobiotics under environmental conditions, in wastewater and in drinking water treatment. Therefore, the stability of frequently applied Gd-based MRI contrast agents towards UV radiation was investigated. The hyphenation of hydrophilic interaction liquid chromatography (HILIC) with inductively coupled plasma mass spectrometry (ICP-MS) and of HILIC with electrospray ionization mass spectrometry (ESI-MS) provided quantitative elemental information as well as structural information. The contrast agents Gd-DTPA, Gd-DOTA and Gd-BT-DO3A showed a high stability in irradiation experiments applying a wavelength range from 220 nm to 500 nm. Nevertheless, the degradation of Gd-BOPTA as well as the formation of Gd-containing transformation products was observed by means of HILIC-ICP-MS. Matrix-dependent irradiation experiments showed a degradation of Gd-BOPTA down to 3% of the initial amount in purified water after 300 min, whereas the degradation was slowed down in drinking water and surface water. Furthermore, it was observed that the sum of species continuously decreased with proceeding irradiation in all matrices. After irradiation in purified water for 300 min only 16% of the sum of species was left. This indicates a release of Gd(III) ions from the complex in course of irradiation. HILIC-ESI-MS measurements revealed that the transformation products mostly resulted from O-dealkylation and N-dealkylation reactions. In good correlation with retention times, the majority of transformation products were found to be more polar than Gd-BOPTA itself. Based on accurate masses, sum formulas were obtained and structures could be proposed.
Collapse
Affiliation(s)
- Marvin Birka
- University of Münster, Institute of Inorganic and Analytical Chemistry, Corrensstraße 28/30, 48149 Münster, Germany
| | - Jörg Roscher
- University of Münster, Institute of Inorganic and Analytical Chemistry, Corrensstraße 28/30, 48149 Münster, Germany
| | - Michael Holtkamp
- University of Münster, Institute of Inorganic and Analytical Chemistry, Corrensstraße 28/30, 48149 Münster, Germany
| | - Michael Sperling
- University of Münster, Institute of Inorganic and Analytical Chemistry, Corrensstraße 28/30, 48149 Münster, Germany; European Virtual Institute for Speciation Analysis (EVISA), Mendelstraße 11, 48149 Münster, Germany
| | - Uwe Karst
- University of Münster, Institute of Inorganic and Analytical Chemistry, Corrensstraße 28/30, 48149 Münster, Germany.
| |
Collapse
|
7
|
Seo SJ, Han SM, Cho JH, Hyodo K, Zaboronok A, You H, Peach K, Hill MA, Kim JK. Enhanced production of reactive oxygen species by gadolinium oxide nanoparticles under core-inner-shell excitation by proton or monochromatic X-ray irradiation: implication of the contribution from the interatomic de-excitation-mediated nanoradiator effect to dose enhancement. Radiat Environ Biophys 2015; 54:423-431. [PMID: 26242374 DOI: 10.1007/s00411-015-0612-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 07/26/2015] [Indexed: 06/04/2023]
Abstract
Core-inner-valence ionization of high-Z nanoparticle atomic clusters can de-excite electrons through various interatomic de-excitation processes, thereby leading to the ionization of both directly exposed atoms and adjacent neutral atoms within the nanoparticles, and to an enhancement in photon-electron emission, which is termed the nanoradiator effect. To investigate the nanoradiator-mediated dose enhancement in the radio-sensitizing of high-Z nanoparticles, the production of reactive oxygen species (ROS) was measured in a gadolinium oxide nanoparticle (Gd-oxide NP) solution under core-inner-valence excitation of Gd with either 50 keV monochromatic synchrotron X-rays or 45 MeV protons. This measurement was compared with either a radiation-only control or a gadolinium-chelate magnetic resonance imaging contrast agent solution containing equal amounts of gadolinium as the separate atomic species in which Gd-Gd interatomic de-excitations are absent. Ionization excitations followed by ROS measurements were performed on nanoparticle-loaded cells or aqueous solutions. Both photoexcitation and proton impact produced a dose-dependent enhancement in the production of ROS by a range of factors from 1.6 to 1.94 compared with the radiation-only control. Enhanced production of ROS, by a factor of 1.83, was observed from Gd-oxide NP atomic clusters compared with the Gd-chelate molecule, with a Gd concentration of 48 μg/mL in the core-level photon excitation, or by a factor of 1.82 under a Gd concentration of 12 μg/mL for the proton impact at 10 Gy (p < 0.02). The enhanced production of ROS in the irradiated nanoparticles suggests the potential for additional therapeutic dose enhancements in radiation treatment via the potent Gd-Gd interatomic de-excitation-driven nanoradiator effect.
Collapse
Affiliation(s)
- Seung-Jun Seo
- Biomedical Engineering and Radiology, School of Medicine, Catholic University of Daegu, Daegu, Korea
| | - Sung-Mi Han
- Anatomy, School of Medicine, Catholic University of Daegu, Daegu, Korea
| | - Jae-Hoon Cho
- Neurosurgery, School of Medicine, Catholic University of Daegu, Daegu, Korea
| | - Kazuyuki Hyodo
- High Energy Accelerator Research Organization (KEK), Photon Factory, Tsukuba, Japan
| | | | - He You
- Shanghai Synchrotron Radiation Facility, Shanghai, China
| | - Ken Peach
- Particle Therapy Cancer Research Institute, University of Oxford, Oxford, UK
| | - Mark A Hill
- Gray Institute for Radiation Oncology and Biology, University of Oxford, Oxford, UK
| | - Jong-Ki Kim
- Biomedical Engineering and Radiology, School of Medicine, Catholic University of Daegu, Daegu, Korea.
| |
Collapse
|
8
|
Marrale M, Brai M, Longo A, Panzeca S, Tranchina L, Tomarchio E, Parlato A, Buttafava A, Dondi D. Neutron ESR dosimetry through ammonium tartrate with low Gd content. Radiat Prot Dosimetry 2014; 159:233-236. [PMID: 24795394 DOI: 10.1093/rpd/ncu135] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This paper continues analyses on organic compounds for application in neutron dosimetry performed through electron spin resonance (ESR). Here, the authors present the results obtained by ESR measurements of a blend of ammonium tartrate dosemeters and gadolinium oxide (5 % by weight). The choice of low amount of Gd is due to the need of improving neutron sensitivity while not significantly influencing tissue equivalence. A study of the effect of gadolinium presence on tissue equivalence was carried out. The experiments show that the neutron sensitivity is enhanced by more than an order of magnitude even with this small additive content. Monte Carlo simulations on the increment of energy release due to gadolinium presence were carried, and the results were in good agreement with the experimental data.
Collapse
Affiliation(s)
- M Marrale
- Dipartimento di Fisica e Chimica, Viale delle Scienze, Ed.18, Palermo I-90128, Italy Gruppo V, INFN, Sezione di Catania, Catania, Italy
| | - M Brai
- Dipartimento di Fisica e Chimica, Viale delle Scienze, Ed.18, Palermo I-90128, Italy Gruppo V, INFN, Sezione di Catania, Catania, Italy
| | - A Longo
- Dipartimento di Fisica e Chimica, Viale delle Scienze, Ed.18, Palermo I-90128, Italy Gruppo V, INFN, Sezione di Catania, Catania, Italy
| | - S Panzeca
- Dipartimento di Fisica e Chimica, Viale delle Scienze, Ed.18, Palermo I-90128, Italy
| | - L Tranchina
- Dipartimento di Fisica e Chimica, Viale delle Scienze, Ed.18, Palermo I-90128, Italy Gruppo V, INFN, Sezione di Catania, Catania, Italy
| | - E Tomarchio
- Dipartimento Energia, Ingegneria dell'Informazione e Modelli Matematici, Viale delle Scienze, Ed.6, Palermo I-90128, Italy
| | - A Parlato
- Dipartimento Energia, Ingegneria dell'Informazione e Modelli Matematici, Viale delle Scienze, Ed.6, Palermo I-90128, Italy
| | - A Buttafava
- Università di Pavia and INFN, Sezione di Pavia, Pavia
| | - D Dondi
- Università di Pavia and INFN, Sezione di Pavia, Pavia
| |
Collapse
|
9
|
Wang P, Qin F, Wang L, Li F, Zheng Y, Song Y, Zhang Z, Cao W. Luminescence and photosensitivity of gadolinium labeled hematoporphyrin monomethyl ether. Opt Express 2014; 22:2414-2422. [PMID: 24663532 DOI: 10.1364/oe.22.002414] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Photodynamic therapy for deep-lying lesions needs an appropriate imaging modality, precise evaluation of tissue oxygen and an effective photosensitizer. Gadolinium based metalloporphyrins Gd(III)-HMME is proposed in this study as a potential multifunctional theranostic agent, as photosensitizer, ratiometric oxygen sensor and MRI contrast agent. The time resolved spectroscopy revealed the luminescence peak of Gd(III)-HMME at 710 and 779 nm with a lifetime of 64 μs in oxygen-free methanol to be phosphorescent. This phosphorescence is strongly dependent on dissolved oxygen concentration. Its intensity in oxygen saturated methanol solution is 21% of that in deoxygenated solution. The singlet oxygen quantum yields ΦΔ of HMME and Gd(III)-HMME in air saturated methanol solution were determined to be 0.79 and 0.40 respectively using comparative spectra method. These phenomena indicate that the oxygen sensibility and production of singlet oxygen of Gd(III)-HMME can fulfill the requirement of PDT treatment.
Collapse
|
10
|
Kim JN, Shin JW, Oh KM, Lee YK, Park SK, Park JK, Nam SH. Optimization of nano-phosphor synthesis by including sensitizer doping for medical X-ray imaging. J Nanosci Nanotechnol 2013; 13:3455-3458. [PMID: 23858878 DOI: 10.1166/jnn.2013.7271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Medical radiation imaging systems employ phosphors such as CaWO4 as X-ray receptor materials. Unfortunately, the conversion efficiencies of these materials are rather low (approx. 5%). Alternatives that comprise a bulk structure have been fabricated from rare earth metals, but they are not efficient enough to produce high quality images. Nano-phosphors do not suffer from the limitations inherent to the bulk structures of conventional phosphors. We examined the effects of sensitizer doping conditions on the optical characteristics and morphology of the rare earth phosphor Gd2O3:Eu to fabricate a novel type of nano-phosphor. We optimized a temperature solution-combustion procedure for producing phosphors doped with 5 wt% Eu. Scanning electron microscopy images showed that the phosphors were 20-30 nm in diameter and X-ray diffraction analysis revealed that they underwent polycrystalline growth upon the addition of a sensitizer, similar to the polycrystalline growth of bulk phosphors. In addition, the phosphors exhibited a strong peak at 613 nm and luminescence similar to conventional phosphors. Phosphors that were produced using citric acid as a sensitizer showed more than double the level of luminescence and could be used to produce higher quality images compared to non-sensitized phosphors. The phosphors also exhibited a high degree of luminescence stability.
Collapse
Affiliation(s)
- Ji-Na Kim
- Department of Medical Image Science, Inje University, 621-749 Gimhae, Republic of Korea
| | | | | | | | | | | | | |
Collapse
|
11
|
Brai M, Marrale M, Gennaro G, Bartolotta A, D'Oca MC, Rosi G. Improvement of ESR dosimetry for thermal neutron beams through the addition of gadolinium. Phys Med Biol 2007; 52:5219-30. [PMID: 17762082 DOI: 10.1088/0031-9155/52/17/008] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In this paper, the addition of gadolinium is proposed as a useful tool to enhance the electron spin resonance (ESR) sensitivity of organic compounds to thermal neutrons. The target of this work is the detection, through the ESR technique, of the thermal neutron fluence in a mixed field of photons and neutrons. Gadolinium was chosen because it has a very high capture cross section to thermal neutrons; its nuclear reaction with thermal neutrons induces complex inner shell transitions that generate, besides other particles, Auger electrons, which in turn release their energy in the neighborhood (only several nanometers) of the place of reaction. Gadolinium was added to two organic molecules: alanine and ammonium tartrate. The main result obtained was a greater neutron sensitivity for dosimeters with gadolinium than for those without gadolinium for both organic molecules used. Since a dosimeter pair is required to discriminate between the two components of a mixed field, we studied the response of each dosimeter pair irradiated in a mixed field. Through a blind test we verified the usefulness of this dosimetric system and we obtained an estimate of the fluence in the mixed field with a relative uncertainty of 3%, when the pair composed of an alanine dosimeter and a dosimeter with alanine and gadolinium is used.
Collapse
Affiliation(s)
- M Brai
- Dipartimento di Fisica e Tecnologie Relative, Università di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo, Italy
| | | | | | | | | | | |
Collapse
|
12
|
Brai M, Gennaro G, Marrale M, Bartolotta A, D'Oca MC. ESR response to γ-rays of alanine pellets containing B(OH)3 or Gd2O3. Appl Radiat Isot 2007; 65:435-9. [PMID: 17158056 DOI: 10.1016/j.apradiso.2006.10.013] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2006] [Revised: 10/17/2006] [Accepted: 10/29/2006] [Indexed: 11/30/2022]
Abstract
ESR response to gamma-irradiation (1-50 Gy) of blends containing alanine and either B(OH)(3) or Gd(2)O(3) is reported. The sensitivity of the alanine--B(OH)(3) blend is comparable to the sensitivity of pure alanine, although its lowest detectable dose, LDD, is smaller ( approximately 1.3 Gy) than that of pure alanine ( approximately 2.9 Gy). Alanine with Gd(2)O(3) is about two times more sensitive than pure alanine, and its LDD is 0.8 Gy. The better sensitivity and LDD are probably due to the high atomic number (Z=64) of gadolinium, which enhances the interaction probability with photons and, consequently, the radical yield. This study suggests that other high-Z atoms may be useful for increasing the sensitivity of the response of alanine to gamma-radiation.
Collapse
Affiliation(s)
- M Brai
- Dipartimento di Fisica e Tecnologie Relative, Università di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo, Italy; Unità CNISM, Palermo and Gruppo V Sezione INFN, Catania
| | | | | | | | | |
Collapse
|
13
|
Li S, Song H, Yu L, Liu Z, Pan G, Yu H, Dai Q, Fan L, Lei Y, Wang T, Ren X, Lu S, Zhao H. Fabrication and photoluminescent properties of Gd2O3 : EU3+ nanowires in AAO template. J Nanosci Nanotechnol 2007; 7:474-80. [PMID: 17450781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Uniform Gd2O3 : Eu3+ nanowires were fabricated by using anodic aluminum oxide template (AAO). The spectral measurements indicate that with the increasing annealing temperature the excitation band of Eu3+ in Gd2O3 : Eu3+ nanowires/AAO shifted blue, the intensity ratio of 5D0-7F2 to 5D0-7F1, decreased, and the lifetime became longer. In the sample annealed at 1000 degrees C two spectral components, the sharper and broader lines were identified, corresponding to two different local environments, the Eu3+ ions in cubic phase and in amorphous phase, respectively. The 5D0-7F1 transitions of Eu3+ ions in cubic phase had longer lifetime than that in amorphous phase. In contrast to the lifetime of the 5D0-7F(j) transitions in the bulk, that in Gd2O3 : Eu3+/AAO composite films increased due to influence of the surrounding media (AAO).
Collapse
Affiliation(s)
- Suwen Li
- Key Laboratory of Excited State Physics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16 Eastern Nan-Hu Road, Changchun 130033, P. R. China
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Lin C, Zhao B, Wang Z, Yu M, Wang H, Kong D, Lin J. Spherical SiO2 @ GdPO4: Eu3+ core-shell phosphors: sol-gel synthesis and characterization. J Nanosci Nanotechnol 2007; 7:542-8. [PMID: 17450792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Nanocrystalline GdPO4 : Eu3+ phosphor layers were coated on non-aggregated, monodisperse and spherical SiO2 particles by Pechini sol-gel method, resulting in the formation of core-shell structured SiO2 @ GdPO4 : Eu3+ particles. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), photoluminescence (PL), low-voltage cathodoluminescence (CL), time-resolved PL spectra and lifetimes were used to characterize the core-shell structured materials. Both XRD and FT-IR results indicate that GdPO4 layers have been successfully coated on the SiO2 particles, which can be further verified by the images of FESEM and TEM. Under UV light excitation, the SiO2 @ GdPO4 : Eu3+ phosphors show orange-red luminescence with Eu3+ 5D0-7F1 (593 nm) as the most prominent group. The PL excitation and emission spectra suggest that an energy transfer occurs from Gd3+ to Eu3+ in SiO2 @ GdPO4 : Eu3+ phosphors. The obtained core-shell phosphors have potential applications in FED and PDP devices.
Collapse
Affiliation(s)
- Cuikun Lin
- Key laboratory of Rare Earth Chemistry and Physics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
| | | | | | | | | | | | | |
Collapse
|
15
|
Abstract
Lithium-gadolinium-borate (LGB) dispersed as microcrystals within the plastic scintillator BC-490 is a promising material for accurate neutron dosimetry in mixed n/gamma fields. Spectral information > 1 MeV is obtained by capture gating proton recoil events in the plastic scintillator to subsequent capture in (6)Li. Below 1 MeV, isolated capture events in either gadolinium or (6)Li give energy information in this region. Discrimination based on capture gating is used to reject false coincidences due to gamma rays or incorrectly gated neutron events. A detailed Monte Carlo model has been created in MCNPX that predicts the energy response of the LGB spectrometer in the capture-gated mode of operation. X-ray microtomography has been performed on the detector in order to obtain the LGB microcrystal distribution within the plastic scintillator, and this is incorporated into the model. The way in which the calculated response functions can be included in an unfolding procedure is outlined.
Collapse
Affiliation(s)
- D V Lewis
- University of Surrey, Guildford, Surrey, UK.
| | | | | | | |
Collapse
|
16
|
Li GZ, Yu M, Wang ZL, Lin J, Wang RS, Fang J. Sol-gel fabrication and photoluminescence properties of SiO2 @ Gd2O3:Eu3+ core-shell particles. J Nanosci Nanotechnol 2006; 6:1416-22. [PMID: 16792374 DOI: 10.1166/jnn.2006.195] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
A uniform nanolayer of europium-doped Gd2O3 was coated on the surface of preformed submicron silica spheres by a Pechini sol-gel process. The resulted SiO2 @ Gd2O3:Eu3+ core-shell structured phosphors were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), photoluminescence (PL) spectra as well as kinetic decays. The XRD results show that the Gd2O3:Eu3+ layers start to crystallize on the SiO2 spheres after annealing at 400 degrees C and the crystallinity increases with raising the annealing temperature. The core-shell phosphors possess perfect spherical shape with narrow size distribution (average size: 640 nm) and non-agglomeration. The thickness of the Gd2O3:Eu3+ shells on the SiO2 cores can be adjusted by changing the deposition cycles (70 nm for three deposition cycles). Under short UV excitation, the obtained SiO2@Gd2O3:Eu3+ particles show a strong red emission with 5D0-7F2 (610 nm) of Eu3+ as the most prominent group. The PL intensity of Eu3+ increases with increasing the annealing temperature and the number of coating cycles.
Collapse
Affiliation(s)
- G Z Li
- Key Laboratory of Rare Earth Chemistry and Physics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
| | | | | | | | | | | |
Collapse
|
17
|
Lebbou K, Perriat P, Tillement O. Recent progress on elaboration of undoped and doped Y2O3, Gd2O3 rare-earth nano-oxide. J Nanosci Nanotechnol 2005; 5:1448-54. [PMID: 16193957 DOI: 10.1166/jnn.2005.312] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Some selected materials with small sizes in the nanometer region are reviewed. Different methods for synthesis of nanoscale materials are classified and discussed. Basic prerequisites for successful use of the materials for nanotechnology application are their synthesis with specific and homogeneous composition and geometry. This review summarizes recent results on nanoscale materials containing optically active lanthanide ion especially focused on Y2O3 and Gd2O3 oxide.
Collapse
Affiliation(s)
- K Lebbou
- Physical Chemistry of Luminescent Materials, Claude Bernard/Lyon 1 University, CNRS UMR 5620, Bat A Kastler, 10 rue Ampere, 69622 Villeurbanne Cedex, France
| | | | | |
Collapse
|
18
|
Naccache R, Vetrone F, Boyer JC, Capobianco JA, Speghini A, Bettinelli M. Visible upconversion emission of Pr3+ doped gadolinium gallium garnet nanocrystals. J Nanosci Nanotechnol 2004; 4:1025-1031. [PMID: 15656197 DOI: 10.1166/jnn.2004.139] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The luminescence properties of a Pr3+-doped gadolinium gallium garnet (GGG, Gd3Ga5O12) nanocrystalline host were investigated. Dominant blue/green emission was observed emanating from the 3P0 --> 3H4 transition after excitation using a wavelength of 457.9 nm. Continuous wave excitation into the 1D2 level of the Pr3+ ion at 606.9 nm transition produced blue upconversion luminescence spectra, ascribed to emission from the 3P1 --> 3H4 and 3P0 --> 3H4 transitions. The increase in the decay times of the observed transitions following excitation with 606.9 nm is indicative of the dominance of an energy transfer upconversion (ETU) mechanism relative to excited state absorption (ESA). Furthermore, blue, green and red upconversion emission was observed from the 3P0, 3P1 and 1D2 states following excitation into the 1G4 energy level with 980 nm. No change in the decay times of the emitting states was observed following excitation with a wavelength of 980 or 457.9 nm; hence, upconversion was determined to primarily occur through ESA. The luminescence properties of the nanocrystals are compared to a single crystal of GGG:Pr3+ (bulk) with an identical Pr3+ concentration (1%).
Collapse
Affiliation(s)
- R Naccache
- Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec, H4B 1R6, Canada
| | | | | | | | | | | |
Collapse
|
19
|
Williams AM, Beeley PA, Spyrou NM. Response of a lithium gadolinium borate scintillator in monoenergetic neutron fields. Radiat Prot Dosimetry 2004; 110:497-502. [PMID: 15353698 DOI: 10.1093/rpd/nch382] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Accurate estimation of neutron dose requires knowledge of the neutron energy distribution in the working environment. Existing neutron spectrometry systems, Bonner spheres for example, are large and bulky, and require long data acquisition times. A portable system that could indicate the approximate neutron energy spectrum in a short time would be extremely useful in radiation protection. A composite scintillator, consisting of lithium gadolinium borate crystals in a plastic scintillator matrix, produced by Photogenics is being tested for this purpose. A prototype device based on this scintillator and digital pulse processing electronics has been calibrated using quasi-monoenergetic neutron fields at the low-scatter facility of the UK National Physical Laboratory (NPL). Energies selected were 144, 250, 565, 1400, 2500 and 5000 keV, with correction for scattered neutrons being made using the shadow cone technique. Measurements were also made in the NPL thermal neutron field. Pulse distributions collected with the digitiser in capture-gated mode are presented, and detection efficiency and energy resolution derived. For comparison, neutron spectra were also collected using the commercially available Microspec N-Probe from Bubble Technology Industries, which consists of an NE213 scintillator and a 3He proportional counter.
Collapse
Affiliation(s)
- A M Williams
- Nuclear Department, HMS Sultan, Gosport, PO12 3BY, UK.
| | | | | |
Collapse
|
20
|
Lee NH, Kim SH, Youk GU, Park IJ, Kim YM. Development of a pMOSFET sensor with a Gd converter for low energy neutron dosimetry. Radiat Prot Dosimetry 2004; 110:277-281. [PMID: 15353659 DOI: 10.1093/rpd/nch159] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A pMOSFET having a 10 microm thick Gadolinium (Gd) layer has been invented as a slow neutron sensor. When slow neutrons are incident to the Gd layer, conversion electrons, which generate electron-hole pairs in the SiO2 layer of the pMOSFET, are generated by a neutron capture process. The holes are easily trapped in the oxide and act as positive-charge centres in the oxide. Due to the induced charges, the threshold turn-on voltage of the pMOSFET is changed. The developed sensors were tested at a neutron beam port of the HANARO research reactor and a 60Co irradiation facility to investigate slow neutron response and gamma ray contamination, respectively. The resultant voltage change was proportional to the accumulated neutron dose and it was very sensitive to slow neutrons. Moreover, ionising radiation contamination was negligible. It can also be used in a mixed radiation field by subtracting the voltage change of a pMOSFET without Gd from that of the Gd-pMOSFET.
Collapse
Affiliation(s)
- N H Lee
- Korea Atomic Energy Research Institute, Taejon, South Korea.
| | | | | | | | | |
Collapse
|
21
|
Abstract
Optical and dosimetric properties of nominally pure CsGd2F7 crystals and of CsGd2F7 crystals doped with various concentrations of Pr3+ ions were investigated. Effects of X, beta and UV irradiation on these crystals were studied. Methods of optical absorption, X and UV excited luminescence, thermoluminescence (TL), phototransferred thermoluminescence and optically stimulated luminescence were used in these investigations. The dependence of the TL efficiency on the radiation dose was found to be linear up to 6 kGy for the 3 at.% Pr3+ doped samples. The crystals containing from 0.3 at.% to 1.0 at.% of Pr3+ ions were found to have the best TL sensitivity and the intensity of the main TL peak in these samples was more than two orders of magnitude higher than that of the pure crystals. The TL sensitivity of the CsGd,F7:Pr3+ crystals was also compared with that of other commonly used TLD materials.
Collapse
|
22
|
Abstract
The phosphor GdO2S:Tb is widely used in camera-based electronic portal imaging devices (EPIDs). There is considerable interest in the application of EPIDs to dosimetry and the verification of intensity modulated radiation therapy produced by dynamic multileaf collimation (DMLC). This paper presents direct measurement of Gd2O2S:Tb phosphor luminescence under 6 MV x-ray irradiation from a linear accelerator using a photomultiplier tube. The luminescence following each radiation pulse (3 micros duration) was observed to decay with a dominant lifetime of 558 micros. Using a specialized electrometer, the temporal variation of the optical signal has been compared with the dose rate incident on the phosphor measured using a semiconductor diode detector. Under dose rates typical of those used in the clinic (1.2 Gy min(-1) to the phosphor), measurements at beam-start confirmed that the optical signal is linear with dose per radiation pulse. Measurements at beam termination following phosphor doses up to 4.4 Gy showed no residual signal associated with long-lived luminescence (afterglow) from the phosphor above the noise level of the optical signal (0.17% standard deviation). This measurement demonstrates that afterglow from Gd2O2S:Tb is not of significance for its application to DMLC verification. Additionally, it was confirmed that the accelerator pulse repetition frequency has no effect on the optical signal from the phosphor in the range 25-400 Hz.
Collapse
Affiliation(s)
- A G Glendinning
- Department of Medical Physics, University Hospitals of Leicester NHS Trust, The Leicester Royal Infirmary, UK.
| | | | | |
Collapse
|
23
|
Akine Y, Tokita N, Matsumoto T, Oyama H, Egawa S, Aizawa O. Radiation effect of gadolinium-neutron capture reactions on the survival of Chinese hamster cells. Strahlenther Onkol 1990; 166:831-3. [PMID: 2267661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In gadolinium-neutron capture reactions, prompt gamma rays with an energy spectrum of up to 7 MeV, X-rays and electrons are released. We measured the effect of radiation as a result of capture reactions on cultured Chinese hamster cells. Cells in the medium containing 5000 ppm gadolinium were exposed to thermal neutrons from a nuclear reactor. The survival curve for those cells exhibited a shoulder in the low neutron fluence region. The survival curve for cells exposed to thermal neutrons in the absence of gadolinium was a simple exponential function. To obtain 10% survival levels, 5.4 x 10(12) neutrons/cm2 were required for cells irradiated in the absence of gadolinium, and 1.55 x 10(12) neutrons/cm2 for those irradiated in the presence of gadolinium. The therapeutic ratio in gadolinium-neutron capture therapy depends on the difference in 157Gd concentrations between the tumor and normal tissues. Thus, our current effort has been to develop a method of selectively delivering 157Gd to tumors.
Collapse
Affiliation(s)
- Y Akine
- Department of Radiation Therapy, National Cancer Center Hospital, Tokyo, Japan
| | | | | | | | | | | |
Collapse
|
24
|
Abstract
Irradiation of plasmid DNA/Gd3+ mixtures with thermal neutrons induces DNA double-strand breaks (dsb). However, the extent of breakage is markedly reduced by sequestering the Gd3+ from DNA by addition of EDTA. Since the 157Gd neutron capture event involves some internal conversion, we suggest that the DNA dsb induction results from Auger electron emission.
Collapse
Affiliation(s)
- R F Martin
- Molecular Science Group, Peter MacCallum Cancer Institute, Melbourne, Victoria, Australia
| | | | | | | |
Collapse
|
25
|
Jori G, Folin M, Gennari G, Galiazzo G, Buso O. Photooxidation of lanthanide ion-lysozyme complexes. A new approach to the evaluation of intramolecular distances in proteins. Photochem Photobiol 1974; 19:419-33. [PMID: 4839496 DOI: 10.1111/j.1751-1097.1974.tb06534.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|