1
|
X-ray computed tomography, electron microscopy, and energy-dispersive X-ray spectroscopy of severed Zelkova serrata roots (Japanese elm tree). Micron 2022; 156:103231. [DOI: 10.1016/j.micron.2022.103231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 02/21/2022] [Accepted: 02/21/2022] [Indexed: 11/23/2022]
|
2
|
Du M, Jacobsen C. Relative merits and limiting factors for x-ray and electron microscopy of thick, hydrated organic materials. Ultramicroscopy 2018; 184:293-309. [PMID: 29073575 PMCID: PMC5696083 DOI: 10.1016/j.ultramic.2017.10.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 10/05/2017] [Indexed: 12/01/2022]
Abstract
Electron and x-ray microscopes allow one to image the entire, unlabeled structure of hydrated materials at a resolution well beyond what visible light microscopes can achieve. However, both approaches involve ionizing radiation, so that radiation damage must be considered as one of the limits to imaging. Drawing upon earlier work, we describe here a unified approach to estimating the image contrast (and thus the required exposure and corresponding radiation dose) in both x-ray and electron microscopy. This approach accounts for factors such as plural and inelastic scattering, and (in electron microscopy) the use of energy filters to obtain so-called "zero loss" images. As expected, it shows that electron microscopy offers lower dose for specimens thinner than about 1 µm (such as for studies of macromolecules, viruses, bacteria and archaebacteria, and thin sectioned material), while x-ray microscopy offers superior characteristics for imaging thicker specimen such as whole eukaryotic cells, thick-sectioned tissues, and organs. The required radiation dose scales strongly as a function of the desired spatial resolution, allowing one to understand the limits of live and frozen hydrated specimen imaging. Finally, we consider the factors limiting x-ray microscopy of thicker materials, suggesting that specimens as thick as a whole mouse brain can be imaged with x-ray microscopes without significant image degradation should appropriate image reconstruction methods be identified.
Collapse
Affiliation(s)
- Ming Du
- Department of Materials Science and Engineering, Northwestern University, 2145 Sheridan Road, Evanston IL 60208, USA
| | - Chris Jacobsen
- Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne IL 60439, USA; Department of Physics & Astronomy, Northwestern University, 2145 Sheridan Road, Evanston IL 60208, USA; Chemistry of Life Processes Institute, Northwestern University, 2170 Campus Drive, Evanston IL 60208, USA.
| |
Collapse
|
3
|
Rinkel J, Magalhães D, Wagner F, Meneau F, Cesar Vicentin F. Detective quantum efficiency for photon-counting hybrid pixel detectors in the tender X-ray domain: application to Medipix3RX. JOURNAL OF SYNCHROTRON RADIATION 2016; 23:206-213. [PMID: 26698065 DOI: 10.1107/s1600577515020226] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 10/26/2015] [Indexed: 06/05/2023]
Abstract
Synchrotron-radiation-based X-ray imaging techniques using tender X-rays are facing a growing demand, in particular to probe the K absorption edges of low-Z elements. Here, a mathematical model has been developed for estimating the detective quantum efficiency (DQE) at zero spatial frequency in the tender X-ray energy range for photon-counting detectors by taking into account the influence of electronic noise. The experiments were carried out with a Medipix3RX ASIC bump-bonded to a 300 µm silicon sensor at the Soft X-ray Spectroscopy beamline (D04A-SXS) of the Brazilian Synchrotron Light Laboratory (LNLS, Campinas, Brazil). The results show that Medipix3RX can be used to develop new imaging modalities in the tender X-ray range for energies down to 2 keV. The efficiency and optimal DQE depend on the energy and flux of the photons. The optimal DQE values were found in the 7.9-8.6 keV photon energy range. The DQE deterioration for higher energies due to the lower absorption efficiency of the sensor and for lower energies due to the electronic noise has been quantified. The DQE for 3 keV photons and 1 × 10(4) photons pixel(-1) s(-1) is similar to that obtained with 19 keV photons. Based on our model, the use of Medipix3RX could be extended down to 2 keV which is crucial for coming applications in imaging techniques at modern synchrotron sources.
Collapse
Affiliation(s)
- Jean Rinkel
- Brazilian Synchrotron Light Laboratory, CNPEM, Rua Giuseppe Máximo Scolfaro 10.000, Caixa Postal 6192, Campinas, SP 13083-970, Brazil
| | - Debora Magalhães
- Brazilian Synchrotron Light Laboratory, CNPEM, Rua Giuseppe Máximo Scolfaro 10.000, Caixa Postal 6192, Campinas, SP 13083-970, Brazil
| | - Franz Wagner
- Brazilian Synchrotron Light Laboratory, CNPEM, Rua Giuseppe Máximo Scolfaro 10.000, Caixa Postal 6192, Campinas, SP 13083-970, Brazil
| | - Florian Meneau
- Brazilian Synchrotron Light Laboratory, CNPEM, Rua Giuseppe Máximo Scolfaro 10.000, Caixa Postal 6192, Campinas, SP 13083-970, Brazil
| | - Flavio Cesar Vicentin
- Brazilian Synchrotron Light Laboratory, CNPEM, Rua Giuseppe Máximo Scolfaro 10.000, Caixa Postal 6192, Campinas, SP 13083-970, Brazil
| |
Collapse
|
4
|
Chen H, Wang Z, Gao K, Hou Q, Wang D, Wu Z. Quantitative phase retrieval in X-ray Zernike phase contrast microscopy. JOURNAL OF SYNCHROTRON RADIATION 2015; 22:1056-61. [PMID: 26134811 DOI: 10.1107/s1600577515007699] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 04/19/2015] [Indexed: 05/20/2023]
Abstract
In recent years, increasing attention has been devoted to X-ray phase contrast imaging, since it can provide high-contrast images by using phase variations. Among the different existing techniques, Zernike phase contrast microscopy is one of the most popular phase-sensitive techniques for investigating the fine structure of the sample at high spatial resolution. In X-ray Zernike phase contrast microscopy, the image contrast is indeed a mixture of absorption and phase contrast. Therefore, this technique just provides qualitative information on the object, which makes the interpretation of the image difficult. In this contribution, an approach is proposed for quantitative phase retrieval in X-ray Zernike phase contrast microscopy. By shifting the phase of the direct light by π/2 and 3π/2, two images of the same object are measured successively. The phase information of the object can then be quantitatively retrieved by a proper combination of the measured images. Numerical experiments were carried out and the results confirmed the feasibility of the proposed method. It is expected that the proposed method will find widespread applications in biology, materials science and so on.
Collapse
Affiliation(s)
- Heng Chen
- Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Zhili Wang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, People's Republic of China
| | - Kun Gao
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, People's Republic of China
| | - Qiyue Hou
- Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, Sichuan 621900, People's Republic of China
| | - Dajiang Wang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, People's Republic of China
| | - Ziyu Wu
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, People's Republic of China
| |
Collapse
|
5
|
Quantitative three-dimensional analysis of poly (lactic-co-glycolic acid) microsphere using hard X-ray nano-tomography revealed correlation between structural parameters and drug burst release. J Pharm Biomed Anal 2015; 112:43-9. [PMID: 25951620 DOI: 10.1016/j.jpba.2015.04.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 04/12/2015] [Accepted: 04/13/2015] [Indexed: 11/21/2022]
Abstract
The objective of this study was to investigate the use of transmission hard X-ray nano-computed-tomography (nano-CT) for characterization of the pore structure and drug distribution in poly (lactic-co-glycolic acid) (PLGA) microspheres encapsulating bovine serum albumin and to study the correlation between drug distribution and burst release. The PLGA microspheres were fabricated using a double-emulsion method. The results of pore structure analysis accessed with nano-CT were compared with those acquired by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Surface pore interconnectivity and surface protein interconnectivity were obtained using combined nano-CT and pixel analysis. The correlation between surface protein interconnectivity with the initial burst release across various tested formulations was also analyzed. The size, shape, and distribution of the pores and protein could be clearly observed in the whole microsphere using nano-CT, whereas only the sectional information was observed using SEM or CLSM. Interconnected pores and surface connected pores could be clearly distinguished in nano-CT, which enables the quantitative analysis of surface pore interconnectivity and surface protein interconnectivity. The surface protein interconnectivity in different formulations correlated well with the burst release at 5-10h. Nano-CT provided a nondestructive, high-resolution, and three-dimensional analysis method to characterize the porous microsphere.
Collapse
|
6
|
Wang D, Li N, Wang Z, Gao K, Zhang Y, Luo Y, Wang S, Bao Y, Shao Q, Wu Z. Three-dimensional study of poly(lactic co-glycolic acid) micro-porous microspheres using hard X-ray nano-tomography. JOURNAL OF SYNCHROTRON RADIATION 2014; 21:1175-1179. [PMID: 25178009 DOI: 10.1107/s1600577514014611] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 06/20/2014] [Indexed: 06/03/2023]
Abstract
Poly(lactic co-glycolic acid) (PLGA) is widely used in diverse fields, especially in delivering biologically active proteins and drugs. For these applications, the knowledge of morphology and microstructure of PLGA micro-porous microspheres is of great importance since they strongly influence the drug delivering efficiency. In this study, micro-porous PLGA microspheres loaded by bovine serum albumin are investigated by using a full-field Zernike phase contrast transmission hard X-ray microscope. From three-dimensional reconstructions and segmentations, fundamental microstructural parameters such as size, shape, distribution and volume ratio among pores and proteins inside PLGA microspheres were obtained. These parameters are useful to understand the relationship between the internal microstructure and drug encapsulation, as well as the drug release efficiency of PLGA microspheres. The presented results demonstrate the capability of hard X-ray nano-tomography to characterize porous microspheres loaded with proteins and drugs, and also open a way to analyse, optimize and design new PLGA microspheres for specific applications.
Collapse
Affiliation(s)
- Dajiang Wang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, 42 Hezuohua South Road, Hefei, Anhui 230029, People's Republic of China
| | - Na Li
- The Third Affiliated Hospital of Sun Yat-sen University, 600 Tianhe Road, Guangzhou, Guangdong 510630, People's Republic of China
| | - Zhili Wang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, 42 Hezuohua South Road, Hefei, Anhui 230029, People's Republic of China
| | - Kun Gao
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, 42 Hezuohua South Road, Hefei, Anhui 230029, People's Republic of China
| | - Yongming Zhang
- The Third Affiliated Hospital of Sun Yat-sen University, 600 Tianhe Road, Guangzhou, Guangdong 510630, People's Republic of China
| | - Yuyan Luo
- The Third Affiliated Hospital of Sun Yat-sen University, 600 Tianhe Road, Guangzhou, Guangdong 510630, People's Republic of China
| | - Shengxiang Wang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, 42 Hezuohua South Road, Hefei, Anhui 230029, People's Republic of China
| | - Yuan Bao
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, 42 Hezuohua South Road, Hefei, Anhui 230029, People's Republic of China
| | - Qigang Shao
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, 42 Hezuohua South Road, Hefei, Anhui 230029, People's Republic of China
| | - Ziyu Wu
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, 42 Hezuohua South Road, Hefei, Anhui 230029, People's Republic of China
| |
Collapse
|
7
|
Vartiainen I, Warmer M, Goeries D, Herker E, Reimer R, David C, Meents A. Towards tender X-rays with Zernike phase-contrast imaging of biological samples at 50 nm resolution. JOURNAL OF SYNCHROTRON RADIATION 2014; 21:790-794. [PMID: 24971976 DOI: 10.1107/s1600577514010388] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 05/07/2014] [Indexed: 06/03/2023]
Abstract
X-ray microscopy is a commonly used method especially in material science application, where the large penetration depth of X-rays is necessary for three-dimensional structural studies of thick specimens with high-Z elements. In this paper it is shown that full-field X-ray microscopy at 6.2 keV can be utilized for imaging of biological specimens with high resolution. A full-field Zernike phase-contrast microscope based on diffractive optics is used to study lipid droplet formation in hepatoma cells. It is shown that the contrast of the images is comparable with that of electron microscopy, and even better contrast at tender X-ray energies between 2.5 keV and 4 keV is expected.
Collapse
Affiliation(s)
| | - Martin Warmer
- Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
| | - Dennis Goeries
- Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
| | - Eva Herker
- Heinrich-Pette-Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Rudolph Reimer
- Heinrich-Pette-Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | | | - Alke Meents
- Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
| |
Collapse
|