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Kitamura Y, Isobe K, Kawabata H, Tsujino T, Watanabe T, Nakamura M, Toyoda T, Okudera H, Okuda K, Nakata K, Kawase T. Quantitative evaluation of morphological changes in activated platelets in vitro using digital holographic microscopy. Micron 2018; 113:1-9. [PMID: 29936304 DOI: 10.1016/j.micron.2018.06.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 05/05/2018] [Accepted: 06/15/2018] [Indexed: 12/13/2022]
Abstract
Platelet activation and aggregation have been conventionally evaluated using an aggregometer. However, this method is suitable for short-term but not long-term quantitative evaluation of platelet aggregation, morphological changes, and/or adhesion to specific materials. The recently developed digital holographic microscopy (DHM) has enabled the quantitative evaluation of cell size and morphology without labeling or destruction. Thus, we aim to validate its applicability in quantitatively evaluating changes in cell morphology, especially in the aggregation and spreading of activated platelets, thus modifying typical image analysis procedures to suit aggregated platelets. Freshly prepared platelet-rich plasma was washed with phosphate-buffered saline and treated with 0.1% CaCl2. Platelets were then fixed and subjected to DHM, scanning electron microscopy (SEM), atomic force microscopy, optical microscopy, and flow cytometry (FCM). Tightly aggregated platelets were identified as single cells. Data obtained from time-course experiments were plotted two-dimensionally according to the average optical thickness versus attachment area and divided into four regions. The majority of the control platelets, which supposedly contained small and round platelets, were distributed in the lower left region. As activation time increased, however, this population dispersed toward the upper right region. The distribution shift demonstrated by DHM was essentially consistent with data obtained from SEM and FCM. Therefore, DHM was validated as a promising device for testing platelet function given that it allows for the quantitative evaluation of activation-dependent morphological changes in platelets. DHM technology will be applicable to the quality assurance of platelet concentrates, as well as diagnosis and drug discovery related to platelet functions.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Kazuhiro Okuda
- Division of Periodontology, Institute of Medicine and Dentistry, Niigata University, Niigata, Japan
| | - Koh Nakata
- Bioscience Medical Research Center, Niigata University Medical and Dental Hospital, Niigata, Japan
| | - Tomoyuki Kawase
- Division of Oral Bioengineering, Institute of Medicine and Dentistry, Niigata University, Niigata, 951-8514, Japan.
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Brand AS, Bullard JW. Dissolution Kinetics of Cubic Tricalcium Aluminate Measured by Digital Holographic Microscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:9645-9656. [PMID: 28841322 DOI: 10.1021/acs.langmuir.7b02400] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In situ digital holographic microscopy is used to characterize the dissolution flux of polycrystalline cubic tricalcium aluminate (C3A-c). The surface dissolves at rates that vary considerably with time and spatial location. This implies a statistical distribution of fluxes, but an approximately steady-state median rate was obtained by using flowing solutions and by reducing the water activity in the solution. The dissolution flux from highly crystalline C3A-c depends on the water activity raised to an empirically derived exponent of 5.2 and extrapolates to a median flux of - 2.1 μmol m-2 s-1 in pure water with an interquartile range of 3.2 μmol m-2 s-1. The flux from a less crystalline source of C3A-c has an empirical water activity exponent of 4.6 and an extrapolated median flux of only -1.4 μmol m-2 s-1 in pure water with an interquartile range of 1.9 μmol m-2 s-1. These data suggest that the bulk dissolution rate of C3A-c can vary by at least 30% from one source to another and that variability in the local rate within a single material is even greater because of the heterogeneous spatial distribution of structural characteristics (i.e., degree of crystallinity, chemical impurities, and defects).
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Affiliation(s)
- Alexander S Brand
- Materials and Structural Systems Division, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - Jeffrey W Bullard
- Materials and Structural Systems Division, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
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Brand AS, Feng P, Bullard JW. Calcite dissolution rate spectra measured by in situ digital holographic microscopy. GEOCHIMICA ET COSMOCHIMICA ACTA 2017; 213:317-329. [PMID: 28894326 PMCID: PMC5590660 DOI: 10.1016/j.gca.2017.07.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Digital holographic microscopy in reflection mode is used to track in situ, real-time nanoscale topography evolution of cleaved (104) calcite surfaces exposed to flowing or static deionized water. The method captures full-field holograms of the surface at frame rates of up to 12.5 s-1. Numerical reconstruction provides 3D surface topography with vertical resolution of a few nanometers and enables measurement of time-dependent local dissolution fluxes. A statistical distribution, or spectrum, of dissolution rates is generated by sampling multiple area domains on multiple crystals. The data show, as has been demonstrated by Fischer et al. (2012), that dissolution is most fully described by a rate spectrum, although the modal dissolution rate agrees well with published mean dissolution rates (e.g., 0.1 µmol m-2 s-1 to 0.3 µmol m-2 s-1). Rhombohedral etch pits and other morphological features resulting from rapid local dissolution appear at different times and are heterogeneously distributed across the surface and through the depth. This makes the distribution in rates measured on a single crystal dependent both on the sample observation field size and on time, even at nominally constant undersaturation. Statistical analysis of the inherent noise in the DHM measurements indicates that the technique is robust and that it likely can be applied to quantify and interpret rate spectra for the dissolution or growth of other minerals.
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Affiliation(s)
- Alexander S Brand
- Materials and Structural Systems Division, Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Pan Feng
- Materials and Structural Systems Division, Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
- Jiangsu Key Laboratory of Construction Materials, School of Material Science and Engineering, Southeast University, Nanjing 211189, China
| | - Jeffrey W Bullard
- Materials and Structural Systems Division, Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
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Feng P, Brand AS, Chen L, Bullard JW. In situ nanoscale observations of gypsum dissolution by digital holographic microscopy. CHEMICAL GEOLOGY 2017; 460:25-36. [PMID: 28827855 PMCID: PMC5562293 DOI: 10.1016/j.chemgeo.2017.04.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Recent topography measurements of gypsum dissolution have not reported the absolute dissolution rates, but instead focus on the rates of formation and growth of etch pits. In this study, the in situ absolute retreat rates of gypsum (010) cleavage surfaces at etch pits, at cleavage steps, and at apparently defect-free portions of the surface are measured in flowing water by reflection digital holographic microscopy. Observations made on randomly sampled fields of view on seven different cleavage surfaces reveal a range of local dissolution rates, the local rate being determined by the topographical features at which material is removed. Four characteristic types of topographical activity are observed: 1) smooth regions, free of etch pits or other noticeable defects, where dissolution rates are relatively low; 2) shallow, wide etch pits bounded by faceted walls which grow gradually at rates somewhat greater than in smooth regions; 3) narrow, deep etch pits which form and grow throughout the observation period at rates that exceed those at the shallow etch pits; and 4) relatively few, submicrometer cleavage steps which move in a wave-like manner and yield local dissolution fluxes that are about five times greater than at etch pits. Molar dissolution rates at all topographical features except submicrometer steps can be aggregated into a continuous, mildly bimodal distribution with a mean of 3.0 µmolm-2 s-1 and a standard deviation of 0.7 µmolm-2 s-1.
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Affiliation(s)
- Pan Feng
- Jiangsu Key Laboratory of Construction Materials, School of Materials Science and Engineering, Southeast University, Nanjing 211189, China
- Materials and Structural Systems Division, Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Alexander S. Brand
- Materials and Structural Systems Division, Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Lei Chen
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Jeffrey W. Bullard
- Materials and Structural Systems Division, Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
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