Two-dimensional agarose gel electrophoresis without gel manipulation

The apparatus and procedure to perform two-dimensional agarose gel electrophoresis without manipulating the gel used for the first electrophoresis (first-dimension gel) have been developed. The procedure is less complex, less damaging to first-dimension gels, and more precise than procedures that require manipulation of the first-dimension gel. When combined with gel-embedding techniques, the procedure presented can be used to perform the second electrophoresis in a gel different from the first-dimension gel. A first-dimension gel too dilute to be manipulated and a more concentrated gel for the second electrophoresis have been used to separate DNA open circles from a mixture of variable-length linear DNAs.     

One-step casting of Laemmli discontinued sodium dodecyl sulfate-polyacrylamide gel electrophoresis gel

A modified Laemmli sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) protocol is described. The new method saves 30 min for gel casting without loss of the resolution power of Laemmli gel. In this method, both the upper and lower gels can be cast at the same time because the lower gel contains 10% glycerol, which generates higher density in the lower gel than in the upper gel.     

Effects of gel thickness on microscopic indentation measurements of gel modulus

In vitro, animal cells are mostly cultured on a gel substrate. It was recently shown that substrate stiffness affects cellular behaviors in a significant way, including adhesion, differentiation, and migration. Therefore, an accurate method is needed to characterize the modulus of the substrate. In situ microscopic measurements of the gel substrate modulus are based on Hertz contact mechanics, where Young's modulus is derived from the indentation force and displacement measurements. In Hertz theory, the substrate is modeled as a linear elastic half-space with an infinite depth, whereas in practice, the thickness of the substrate, h, can be comparable to the contact radius and other relevant dimensions such as the radius of the indenter or steel ball, R. As a result, measurements based on Hertz theory overestimate the Young's modulus. In this work, we discuss the limitations of Hertz theory and then modify it, taking into consideration the nonlinearity of the material and large deformation using a finite-element method. We present our results in a simple correction factor, ψ, the ratio of the corrected Young's modulus and the Hertz modulus in the parameter regime of δ/h ≤ min (0.6, R/h) and 0.3 ≤ R/h ≤ 12.7. The ψ factor depends on two dimensionless parameters, R/h and δ/h (where δ is the indentation depth), both of which are easily accessible to experiments. This correction factor agrees with experimental observations obtained with the use of polyacrylamide gel and a microsphere indentation method in the parameter range of 0.1 ≤ δ/h ≤ 0.4 and 0.3 ≤ R/h ≤ 6.2. The effect of adhesion on the use of Hertz theory for small indentation depth is also discussed.     

Ausgestorbene V?gel

Ohne ZusammenfassungNach Strickland's the Dodo and its Kindred und anderen Quellen.     

Seeing gel wells well

Indicator dyes have been incorporated in the stacking gel monomer used in acrylamide gels to render readily visible and delineate the sample wells. Some dyes, such as bromphenol blue, migrate during the electrophoresis, whereas others, such as the ortho-unsubstituted phenol red, become chemically bound to the polymerized gel. The method can be used for agarose gels.     

Radiolucent prosthetic gel.

The successful use of silicone breast implants is complicated by their interference with mammography. We have evaluated clinically available implant filling materials and found that a new Bio-Oncotic gel approximates the radiolucency of normal breast tissue. Silicone implants completely obscure areas of the breast in mammography. Recently proposed as a filler material, peanut oil is significantly more radiolucent than normal tissue. Physiologic saline solution compares favorably as a tissue-density-simulating substance. However, saline's lack of lubricating properties results in leakage, making it less than optimal. Bio-Oncotic gel is biologically compatible. We conclude that this gel is the most appropriate filler for breast prostheses. Clinical studies are indicated.