Angiogenesis

 
If individual tumor cells grow into a macroscopic tumor they drastically increase their demand for oxygen and nutrients. An important example of angiogenesis is the generation of new blood vessels to feed a tumor. In vitro angiogenesis assays provide a better understanding of these processes on a cellular and molecular level.

The µ-Slide Angiogenesis was designed for biomedical and pharmaceutical research. It can be used with all common gel matrices, like Matrigel™, collagen gels, and hyaluronic acid gels. Only 10 µl gel per well are needed.

Angiogenesis assays in vitro

Cells on gel matrices can be used to monitor their ability to form new vessels. The tube formation assay is done by seeding single cells and observing characteristic patterns. To carry out the sprouting assays either spheroids or pieces of tissue e.g. from aorta are placed on the gel matrix. All these assays share a need for a well defined thickness of the gel layer underneath.

The assays performed in the µ-Slide Angiogenesis benefit from a well defined thickness of the gel matrices. Besides reproducible cell culture conditions, the cells are placed in one optical plane.

Optical improvements

The μ-Slide Angiogenesis was primarily developed to simplify the tube formation assay of endothelial cells on Matrigel™. This kind of assay is usually done in multi-well plates. In large wells, such as 6 or 12 well plates, the great amount of gel matrix required is very expensive. Using smaller wells causes a meniscus formation of the gel surface which leads to inhomogeneous cell distribution patterns. Also, the meniscus does not allow the cells to be in one optical plane.

Another meniscus (formed by the air-liquid interface) restricts phase contrast to a small area in the center of the well.

The µ-Slide Angiogenesis solves these problems providing a 4 mm well in a 5 mm well. This optical improvement is called “well in a well“.

Filling the smaller well with exactly 10 µl of gel will result in a plane gel surface. Filling the major well with exactly 50 µl also avoids meniscus formation on the air-liquid interface.

3D Cell cultures

The “well in a well“ feature of the µ-Slide Angiogenesis also supports the microscopy of cells embedded in gel matrices. 3D cell cultures mimick in vivo conditions e.g. of cancer cells and hepatocytes. Also non-adherent cells such as blood cells or bacteria can be immobilized for enhanced microscopy access.

The amounts of gel matrix and medium volume are balanced for the nutrient supply of those 3D cell cultures with low and medium cell densities.