Cellular Angiogenesis Assay
Cell-Based Assays

In Vitro Angiogenesis Assay for Drug Testing

The Angiogenesis Assay allows for the evaluation of pro- or anti-angiogenic effects of drugs on HUVEC sprouting capacity on a cellular basis.

Angiogenesis, the formation of new blood vessels, is a physiological process during growth and development. Beyond that, angiogenesis is necessary for tumor growth and is involved in other pathological disorders (e.g. psoriasis, macular degeneration).

The In Vitro Angiogenesis Assay is a vessel sprouting assay that mimics the in vivo situation with respect to the first stages of the angiogenic cascade, (i) the sprouting in a 3D environment promotes cell-cell signaling between the endothelial cells, (ii) the surrounding matrix is degraded before the invasion, (iii) the spheroids used in the angiogenesis assay generate sprouts that are close to the physiological arrangement of endothelial cell vessels

  • Vessel sprouting can be induced by VEGF-A, FGF-1, FGF-2, DFO, or others
  • IC50 determination can be performed for angio-stimulating and angio-inhibiting compounds
  • The in vitro angiogenesis assay is reproducible and robust despite its complexity

Vessel sprouting

In the angiogenesis assay endothelial cell spheroids will sprout new capillary-like vessels when stimulated with pro-angiogenic factors like VEGF-A.

The number and length of the sprouts correspond to the angiogenic activity of the endothelial cells. Pro-angiogenic compounds induce sprouting; whereas angiogenesis inhibitors prevent new vessel formation.

angiogenesis assay for vessel sprouting of human endothelial cells in the cell based angiogenesis assay

angiogenesis assay for vessel sprouting of human endothelial cells in the cell based angiogenesis assay

Sprouting Assay Details

  • Assay Procedure
  • Example data
  • Screening Formats
Assay Procedure


assay procedure of cell based angiogenesis assays with human endothelial spheroids


Endothelial cells aggregate to form spheroids in a hanging drop system. The spheroids are pipetted into multi-well plates in a collagen matrix where the test compounds and stimulation factors are added. During a 24-hour period, vessels sprout from the spheroids and are quantified by measuring their length to determine the cumulative sprout length.

Example data

angiogenesis assay example for sprouting assay

Two angiogenesis inhibitors were tested for inhibition of endothelial cell sprouting activated by two factors, VEGF-A or DFO (a metal chelator that induced hypoxia) and fibroblast scattering. In the upper panel, the inhibitor is active on endothelial cell sprouting but does not affect fibroblast scattering. In contrast, the drug in the lower panel inhibits both endothelial cell sprouting and fibroblast scattering.

Screening Formats

Setup: IC50 value determination and single concentration testing are possible. Drug combination treatment is an option.

We offer a variety of stimulating factors for the induction of vessel sprouting such as VEGF-A, DFO, FGF-1, FGF-2, and more.

Testing of pro- and anti-angiogenic drug candidates is possible.

Controls: Stimulus-free media only is the low control of vessel sprouting. VEGF-A only is the high control. Treatment with a reference inhibitor is included to ensure quality control.

Report: A detailed report including assay conditions, methodology, and comprehensive evaluation of data as well as raw data for each analysis will be provided. Photographs are optional.

Turnaround time: Results will be available within about 3 weeks.

Screening facility: The assay is performed in Freiburg, Germany.

Compound requirements: In brief: 100 µl of the stock solution with 100x of the highest assay concentration or the equivalent of solid material.