scholarly journals Two-Dimensional (2D) and Three-Dimensional (3D) Cell Culturing in Drug Discovery

Author(s):  
Jitcy Saji Joseph ◽  
Sibusiso Tebogo Malindisa ◽  
Monde Ntwasa
2019 ◽  
Author(s):  
Tiffany Miller

<p>Bone marrow derived stem cells express biomarkers capable of facilitating adhesion to the cell culturing microenvironment, thereby, influencing their proliferation, migration, and differentiation. In particular, biological biomarkers of mesenchymal stem cells include, but are not limited to, CD14-, CD19-, CD34-, CD45-, CD29, CD44, CD73+, CD90+, CD105+, CD106, CD166, Stro-1, and HLADR. The relationship between the stem cell biology and the materials and methods forming a cell culturing microenvironment serves as a critical aspect in the successful adhesion and growth within two-dimensional cell culture microenvironments such as polystyrene, laminin, fibronectin, or poly-L-lysine and within three-dimensional cell culture microenvironments such as hydrogel, ceramic, collagen, polymer based nanofibers, agitation, forced floating, and hang drop systems. Further, electrical stimulation of the stem cells may be implemented during the cell culturing process to measure stem cell growth and to determine stem cell viability. In addition, electrical stimulation of implanted stem cells may facilitate tracking by measuring stem cell migration distance and travel area. Although many biochemical and inflammatory biomarkers are expressed based on severity in stroke including, but not limited to, Interluken-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and glutamate (Glu), current methodologies of stem cell directing lack localization and biological effector specificity. Biological effector bound magnetic particle stem cells may serve as a potential treatment method in ischemic stroke. In particular, a stem cell biomarker may be configured to communicate with inflammatory biomarkers, thus, more efficiently delivering the stem cells to site specific areas having the most severely affected <i>in-vivo</i> biochemical microenvironments.</p>


2019 ◽  
Author(s):  
Tiffany Miller

<p>Bone marrow derived stem cells express biomarkers capable of facilitating adhesion to the cell culturing microenvironment, thereby, influencing their proliferation, migration, and differentiation. In particular, biological biomarkers of mesenchymal stem cells include, but are not limited to, CD14-, CD19-, CD34-, CD45-, CD29, CD44, CD73+, CD90+, CD105+, CD106, CD166, Stro-1, and HLADR. The relationship between the stem cell biology and the materials and methods forming a cell culturing microenvironment serves as a critical aspect in the successful adhesion and growth within two-dimensional cell culture microenvironments such as polystyrene, laminin, fibronectin, or poly-L-lysine and within three-dimensional cell culture microenvironments such as hydrogel, ceramic, collagen, polymer based nanofibers, agitation, forced floating, and hang drop systems. Further, electrical stimulation of the stem cells may be implemented during the cell culturing process to measure stem cell growth and to determine stem cell viability. In addition, electrical stimulation of implanted stem cells may facilitate tracking by measuring stem cell migration distance and travel area. Although many biochemical and inflammatory biomarkers are expressed based on severity in stroke including, but not limited to, Interluken-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and glutamate (Glu), current methodologies of stem cell directing lack localization and biological effector specificity. Biological effector bound magnetic particle stem cells may serve as a potential treatment method in ischemic stroke. In particular, a stem cell biomarker may be configured to communicate with inflammatory biomarkers, thus, more efficiently delivering the stem cells to site specific areas having the most severely affected <i>in-vivo</i> biochemical microenvironments.</p>


2016 ◽  
Vol 6 (1) ◽  
pp. 20150095 ◽  
Author(s):  
Elliot L. Elson ◽  
Guy M. Genin

The functions, form and mechanical properties of cells are inextricably linked to their extracellular environment. Cells from solid tissues change fundamentally when, isolated from this environment, they are cultured on rigid two-dimensional substrata. These changes limit the significance of mechanical measurements on cells in two-dimensional culture and motivate the development of constructs with cells embedded in three-dimensional matrices that mimic the natural tissue. While measurements of cell mechanics are difficult in natural tissues, they have proven effective in engineered tissue constructs, especially constructs that emphasize specific cell types and their functions, e.g. engineered heart tissues. Tissue constructs developed as models of disease also have been useful as platforms for drug discovery. Underlying the use of tissue constructs as platforms for basic research and drug discovery is integration of multiscale biomaterials measurement and computational modelling to dissect the distinguishable mechanical responses separately of cells and extracellular matrix from measurements on tissue constructs and to quantify the effects of drug treatment on these responses. These methods and their application are the main subjects of this review.


Author(s):  
H.A. Cohen ◽  
T.W. Jeng ◽  
W. Chiu

This tutorial will discuss the methodology of low dose electron diffraction and imaging of crystalline biological objects, the problems of data interpretation for two-dimensional projected density maps of glucose embedded protein crystals, the factors to be considered in combining tilt data from three-dimensional crystals, and finally, the prospects of achieving a high resolution three-dimensional density map of a biological crystal. This methodology will be illustrated using two proteins under investigation in our laboratory, the T4 DNA helix destabilizing protein gp32*I and the crotoxin complex crystal.


Author(s):  
B. Ralph ◽  
A.R. Jones

In all fields of microscopy there is an increasing interest in the quantification of microstructure. This interest may stem from a desire to establish quality control parameters or may have a more fundamental requirement involving the derivation of parameters which partially or completely define the three dimensional nature of the microstructure. This latter categorey of study may arise from an interest in the evolution of microstructure or from a desire to generate detailed property/microstructure relationships. In the more fundamental studies some convolution of two-dimensional data into the third dimension (stereological analysis) will be necessary.In some cases the two-dimensional data may be acquired relatively easily without recourse to automatic data collection and further, it may prove possible to perform the data reduction and analysis relatively easily. In such cases the only recourse to machines may well be in establishing the statistical confidence of the resultant data. Such relatively straightforward studies tend to result from acquiring data on the whole assemblage of features making up the microstructure. In this field data mode, when parameters such as phase volume fraction, mean size etc. are sought, the main case for resorting to automation is in order to perform repetitive analyses since each analysis is relatively easily performed.


Author(s):  
Yu Liu

The image obtained in a transmission electron microscope is the two-dimensional projection of a three-dimensional (3D) object. The 3D reconstruction of the object can be calculated from a series of projections by back-projection, but this algorithm assumes that the image is linearly related to a line integral of the object function. However, there are two kinds of contrast in electron microscopy, scattering and phase contrast, of which only the latter is linear with the optical density (OD) in the micrograph. Therefore the OD can be used as a measure of the projection only for thin specimens where phase contrast dominates the image. For thick specimens, where scattering contrast predominates, an exponential absorption law holds, and a logarithm of OD must be used. However, for large thicknesses, the simple exponential law might break down due to multiple and inelastic scattering.


Author(s):  
D. E. Johnson

Increased specimen penetration; the principle advantage of high voltage microscopy, is accompanied by an increased need to utilize information on three dimensional specimen structure available in the form of two dimensional projections (i.e. micrographs). We are engaged in a program to develop methods which allow the maximum use of information contained in a through tilt series of micrographs to determine three dimensional speciman structure.In general, we are dealing with structures lacking in symmetry and with projections available from only a limited span of angles (±60°). For these reasons, we must make maximum use of any prior information available about the specimen. To do this in the most efficient manner, we have concentrated on iterative, real space methods rather than Fourier methods of reconstruction. The particular iterative algorithm we have developed is given in detail in ref. 3. A block diagram of the complete reconstruction system is shown in fig. 1.


Author(s):  
A.M. Jones ◽  
A. Max Fiskin

If the tilt of a specimen can be varied either by the strategy of observing identical particles orientated randomly or by use of a eucentric goniometer stage, three dimensional reconstruction procedures are available (l). If the specimens, such as small protein aggregates, lack periodicity, direct space methods compete favorably in ease of implementation with reconstruction by the Fourier (transform) space approach (2). Regardless of method, reconstruction is possible because useful specimen thicknesses are always much less than the depth of field in an electron microscope. Thus electron images record the amount of stain in columns of the object normal to the recording plates. For single particles, practical considerations dictate that the specimen be tilted precisely about a single axis. In so doing a reconstructed image is achieved serially from two-dimensional sections which in turn are generated by a series of back-to-front lines of projection data.


Author(s):  
Douglas L. Dorset ◽  
Andrew K. Massalski

Matrix porin, the ompF gene product of E. coli, has been the object of a electron crystallographic study of its pore geometry in an attempt to understand its function as a membrane molecular sieve. Three polymorphic forms have been found for two-dimensional crystals reconstituted in phospholipid, two hexagonal forms with different lipid content and an orthorhombic form coexisting with and similar to the hexagonal form found after lipid loss. In projection these have been shown to retain the same three-fold pore triplet geometry and analyses of three-dimensional data reveal that the small hexagonal and orthorhombic polymorphs have similar structure as well as unit cell spacings.


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