Introduction
Matrigel is a natural extracellular matrix (ECM) secreted by Englebreth-Holm Swam mouse sarcoma. It has numerous applications in 2D and 3D cell culture for its ability to mimic in vivo environments. However, its complex and highly variable composition can negatively affect experimental reproducibility and accuracy. Furthermore, components naturally occurring in Matrigel can interfere with assays generating false positives or false negatives. Synthetic hydrogels with their well-defined chemical composition are an appealing alternative to Matrigel and other natural ECMs. This study utilizes ProPlate® chambers to generate a synthetic hydrogel array to identify environments suitable for embryonic stem cell expansion and vascular toxicity studies.
Identification of synthetic hydrogels that support endothelial network formation to study vascularization mechanisms.
Over 1,200 photo cross-linked, cell-degradable polyethylene glycol (PEG) hydrogels have been evaluated for vascular screening assays, human embryonic stem cell adhesion and maintenance of pluripotency. Synthetic hydrogels were arrayed onto glass slides. Individual wells, created by affixing ProPlate Multi-Array chambers, were submerged with different culture media depending on the cell type. Peptides and growth factors that promote endothelial network formation were also added to the cultures.
Synthetic hydrogels were demonstrated to
- Support consistent and reproducible endothelial network formation by human umbilical vein endothelial cells (HUVECs) as well as human induced pluripotent stem cells (iPSC-ECs)
- Demonstrated superior reproducibility in vascular inhibition assays
- Increased sensitivity of HUVECs cells to VEGF inhibitors
Synthetic hydrogels were only minimally affected by Suramin hydrochloride which has been shown to cause Matrigel dissolution. The consequent disruption of endothelial network formation could be attributable to the effect on Matrigel rather than angiogenesis inhibition, thus affecting results interpretation.
A panel of 38 unique chemicals, comprising a range of anti-angiogenetic activity, was tested. Results indicated that cells cultured in the presence of synthetic hydrogels have higher sensitivity to anti-angiogenic compounds than cells cultured in the presence of Matrigel. Additional experiments, including testing inhibitors at different concentrations, should be conducted before conclusive data can be derived.
Conclusions
This work demonstrates that synthetic hydrogels can out-perform a natural biomaterial and that they can be utilized in applications requiring a complex multicellular tissue model for drug and toxicity screening. They enabled evaluation of known pharmacological inhibitors of angiogenesis and offer improved reproducibility, superior screening performance within a chemically defined environment, free of the components that can potentially interfere with cell growth and drug screening.
For more information: https://www.nature.com/articles/s41551-017-0096
