scholarly journals Faithful Scanning Electron Microscopic (SEM) visualization of 3D printed alginate-based scaffolds

2020 ◽  
Author(s):  
Marcus Koch ◽  
Małgorzata K. Włodarczyk-Biegun

AbstractThe morphological characterization of 3D printed hydrogel-based scaffolds is essential for monitoring their size, shape, surface texture and internal structure. Among other microscopic techniques, Scanning Electron Microscopy (SEM) is capable of visualizing nearly all kinds of materials at different length scales, with exceptional precision, if investigation under vacuum is possible. However, due to the high water content of hydrogel-based scaffolds and the connected volume change after drying, special preparation techniques are necessary to stabilize the 3D architecture when imaged by SEM. Here we present a straightforward cryo-SEM technique to visualize 3D printed hydrogel-based alginate scaffolds. By use of a homemade cryo-SEM holder and plunge-freezing in liquid ethane, scaffolds are visualized from the top and cross-sectional view at different magnifications. The proposed method is compared with SEM imaging in different modes (cyro-SEM, conventional SEM, ESEM) following other commonly used sample preparation techniques, such as plunging in liquid nitrogen, air-drying, freeze-drying and plunging in liquid ethane after graded dehydration. These approaches, except ESEM, lead to shrinkage, deformation, distortion or disintegration of the scaffolds and consequently give rise to artifacts in imaging. The presented results indicate that cryo-SEM after plunging in liquid ethane allows for the most faithful and time-efficient visualization of 3D printed alginate scaffolds.

Author(s):  
Tokio Nei ◽  
Haruo Yotsumoto ◽  
Yoichi Hasegawa ◽  
Yuji Nagasawa

In order to observe biological specimens in their native state, that is, still containing their water content, various methods of specimen preparation have been used, the principal two of which are the chamber method and the freeze method.Using its recently developed cold stage for installation in the pre-evacuation chamber of a scanning electron microscope, we have succeeded in directly observing a biological specimen in its frozen state without the need for such conventional specimen preparation techniques as drying and metallic vacuum evaporation. (Echlin, too, has reported on the observation of surface structures using the same freeze method.)In the experiment referred to herein, a small sliced specimen was place in the specimen holder. After it was rapidly frozen by freon cooled with liquid nitrogen, it was inserted into the cold stage of the specimen chamber.


Author(s):  
H. Takaoka ◽  
M. Tomita ◽  
T. Hayashi

High resolution transmission electron microscopy (HRTEM) is the effective technique for characterization of detailed structure of semiconductor materials. Oxygen is one of the important impurities in semiconductors. Detailed structure of highly oxygen doped silicon has not clearly investigated yet. This report describes detailed structure of highly oxygen doped silicon observed by HRTEM. Both samples prepared by Molecular beam epitaxy (MBE) and ion implantation were observed to investigate effects of oxygen concentration and doping methods to the crystal structure.The observed oxygen doped samples were prepared by MBE method in oxygen environment on (111) substrates. Oxygen concentration was about 1021 atoms/cm3. Another sample was silicon of (100) orientation implanted with oxygen ions at an energy of 180 keV. Oxygen concentration of this sample was about 1020 atoms/cm3 Cross-sectional specimens of (011) orientation were prepared by argon ion thinning and were observed by TEM at an accelerating voltage of 400 kV.


2001 ◽  
Vol 707 ◽  
Author(s):  
Ian C. Bache ◽  
Catherine M. Ramsdale ◽  
D. Steve Thomas ◽  
Ana-Claudia Arias ◽  
J. Devin MacKenzie ◽  
...  

ABSTRACTCharacterising the morphology of thin films for use in device applications requires the ability to study both the structure within the plane of the film, and also through its thickness. Environmental scanning electron microscopy has proved to be a fruitful technique for the study of such films both because contrast can be seen within the film without the need for staining (as is conventionally done for electron microscopy), and because cross-sectional images can be obtained without charging artefacts. The application of ESEM to a particular blend of relevance to photovoltaics is described.


Author(s):  
Pietro Russo ◽  
Antonio Langella ◽  
Giulia Leone ◽  
Gennaro D'Angelo ◽  
Pietro Ferraro ◽  
...  

2016 ◽  
Vol 34 (2) ◽  
pp. 412-417
Author(s):  
Esra Öztürk

AbstractIn this work, aluminate type phosphorescence materials were synthesized via the solid state reaction method and the photoluminescence (PL) properties, including excitation and emission bands, were investigated considering the effect of trace amounts of activator (Eu3+) and co-activator (Dy3+). The estimated thermal behavior of the samples at certain temperatures (> 1000 °C) during heat treatment was characterized by differential thermal analysis (DTA) and thermogravimetry (TG). The possible phase formation was characterized by X-ray diffraction (XRD). The morphological characterization of the samples was performed by scanning electron microscopy (SEM). The PL analysis of three samples showed maximum emission bands at around 610 nm, and additionally near 589 nm, 648 nm and 695 nm. The bands were attributed to typical transitions of the Eu3+ ions.


2015 ◽  
Vol 1109 ◽  
pp. 381-384
Author(s):  
M. Safwan Azmi ◽  
Sharipah Nadzirah ◽  
Uda Hashim

The purpose of this paper is to study the morphological characterization of aluminum interdigitated electrodes (IDE) of different gap sizes on silicon substrate. The electrodes were fabricated using standard photolithography process and were done so with sizes of 12 μm, 10 μm and 7 μm. The electrodes were morphologically characterized using scanning electron microscope (SEM) and high-powered microscope (HPM).Keywords: morphological, interdigitated electrodes, aluminum


2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
A. Hedayat ◽  
J. Szpunar ◽  
N. A. P. Kiran Kumar ◽  
R. Peace ◽  
H. Elmoselhi ◽  
...  

Background. Morphological characterization of hemodialysis membranes is necessary to improve pore design.Aim. To delineate membrane pore structure of a high flux filter, Polyflux 210H.Methods. We used a Joel JSM-6010LV scanning electron microscope (SEM) and a SU6600 Hitachi field emission scanning electron microscope (FESEM) to characterize the pore and fiber morphology. The maximal diameters of selected uremic toxins were calculated using the macromolecular modeling Crystallographic Object-Oriented Toolkit (COOT) software.Results. The mean pore densities on the outermost and innermost surfaces of the membrane were 36.81% and 5.45%, respectively. The membrane exhibited a tortuous structure with poor connection between the inner and outer pores. The aperture’s width in the inner surface ranged between 34 and 45 nm, which is 8.76–11.60 times larger than the estimated maximum diameter ofβ2-microglobulin (3.88 nm).Conclusion. The results suggest that the diameter size of inner pore apertures is not a limiting factor to middle molecules clearance, the extremely diminished density is. Increasing inner pore density and improving channel structure are strategies to improve clearance of middle molecules.


2019 ◽  
Vol 125 (3) ◽  
pp. 521-532
Author(s):  
Emma Sarath ◽  
Kazune Ezaki ◽  
Takenori Sasaki ◽  
Yu Maekawa ◽  
Yuji Sawada ◽  
...  

Abstract Background and aims Domatia are plant structures within which organisms reside. Callicarpa saccata (Lamiaceae) is the sole myrmecophyte, or ‘ant plant’, that develops foliar (leaf-borne) myrmeco-domatia in this genus. In this work we examined domatium development in C. saccata to understand the developmental processes behind pouch-like domatia. Methods Scanning electron microscopy, sectioning and microcomputed tomography were carried out to compare the leaves of C. saccata with those of the closely related but domatia-less myrmecophyte Callicarpa subaequalis, both under cultivation without ants. Key results Callicarpa saccata domatia are formed as a result of excess cell proliferation at the blade/petiole junctions of leaf primordia. Blade/petiole junctions are important meristematic sites in simple leaf organogenesis. We also found that the mesophyll tissue of domatia does not clearly differentiate into palisade and spongy layers. Conclusions Rather than curling of the leaf margins, a perturbation of the normal functioning of the blade/petiole junction results in the formation of domatium tissue. Excess cell proliferation warps the shape of the blade and disturbs the development of the proximal–distal axis. This process leads to the generation of distinct structures that facilitate interaction between C. saccata and ants.


Zootaxa ◽  
2011 ◽  
Vol 2906 (1) ◽  
pp. 52
Author(s):  
XIAOQIANG LI ◽  
BINGZHONG REN ◽  
YUTING ZOU ◽  
JIAN ZHANG ◽  
YINLIANG WANG

The present study compares the proventricular morphology, analyzed under optic microscope and scanning electron microscopy (SEM), among ten Grylloidea species. The result showed that the size of proventriculus was of critical value. Internally, the main differences were the number of sclerotized appendix (sa), middle denticles (md) and lateral denticles (ld), and the structure of lateral teeth (lt). In addition, we analyzed the crickets’ feeding habits and note that the the proventriculus possesses highly sclerotized projections which act in the selection of victuals. The morphology of proventriculus is closely related to feeding habits. A clustering analysis of seven features of the proventriculus was constructed. It revealed that the proventriculus had significance for taxonomy and species relationships. Observations on morphological characterization of proventricular morphology will be useful in future studies of the feeding habits and phylogeny of crickets.


Sign in / Sign up

Export Citation Format

Share Document