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Stem Cell Biology

HyStem™ Cell Culture

The First Customizable Synthetic ECM

Sigma® is pleased to introduce HyStem™, the first customizable synthetic ECM, to enable three-dimensional culture of stem cells.

Customizable
The HyStem platform offers you, the researcher, control over growth factor incorporation, attachment factor incorporation, ECM protein incorporation, rigidity of the hydrogel, and cell encapsulation vs. top plating

Synthetic
Because HyStem is a synthesized matrix and not a biological extract, researchers are able to closely control the composition of their cells’ environment. HyStem’s components include chemically synthesized HyStem (thiolated Hyaluronic acid), Extralink (thiol-reactive crosslinker), and degassed Water and biologically purified Gelin-S (denatured collagen).

Biologically Accurate
HyStem kits are optimal for culturing stem cells whose natural environments are rich in hyaluronic acid. The HyStem hydrogel scaffold closely mimics the rich, natural extracellular matrix environment, complete with hyaluronic acid and collagen fibrils, while offering the flexibility to customize with appropriate growth factors, attachment factors, and proteins.

The HyStem platform includes three unique members

HyStem

Cell Culture Scaffold Kit: For researchers who require an animal component free system, for researchers who will customize with their own attachment factors and/or ECM proteins/peptides, and for researchers who require a minimal number of cell attachment sites

HyStem-C

Cell Culture Scaffold Kit: For researchers who require a large number of generalized cell attachment sites for their stem cell culture(s).

HyStem-HP

Cell Culture Scaffold Kit: For researchers planning to incorporate and gradually release growth factors into the stem cell environment.

Hyaluronan Relevancy for Stem Cells

HyStem hydrogels are composed of HyStem (thiol-modified hyaluronan, HA) and Extralink™ (thiol-reactive crosslinking agent). HA is the simplest glycosaminoglycan (a class of negatively charged polysaccharides) and a major constituent of the ECM1,2. Embryonic ECM possesses a high quantity of glycosaminoglycans of which HA is predominant3. Human embryonic stem cells (H1, H9 and H13 lines) have been shown to express both CD44 and CD168 (RHAMM), which are HA receptors. Human embryonic stem cells (hESCs) have also been cultivated by encapsulating them in HA hydrogels. These cells were grown for 15 days without detectable differentiation. After recovery from the hydrogels, the hESCs could be differentiated using endothelial growth media supplemented with VEGF3.

HA is also present in large amounts in the ECM of embryonic livers, fetal livers and the putative stem cell niche within the liver (the Canals of Hering). Hepatic stem and progenitors cells (hepatoblasts) have been successfully cultured for over 4 weeks without differentiation when encapsulated in HA hydrogels and grown with a defined media (Kubota’s medium). Additionally, these hepatic progenitor cells express CD44 at high levels4.

References

  1. X.Z. Shu, S. Ahmad, Y. Liu, and G.D. Prestwich, “Synthesis and Evaluation of Injectable, in situ Crosslinkable Synthetic Extracellular Matrices (sECMs) for  Tissue Engineering,” J. Biomed Mater. Res. A, 79A(4), 901-912 (2006).
  2. X.Z. Shu, Y. Liu, F. Palumbo, G.D. Prestwich, “Disulfide-crosslinked Hyaluronan-Gelatin Hydrogel Films: A Covalent Mimic of the Extracellular Matrix for In Vitro Cell Growth,” Biomaterials, 24, 3825-3834 (2003).
  3. S. Gerecht, J.A. Brudick, L.S. Ferreira, S.A. Townsend, R. Langer, G. Vunjak-Novakovic, “Hyaluronic acid hydrogel for controlled self-renewal and differentiation of human embryonic stem cells,” PNAs 104(27): 11298-11303.
  4. Unpublished data from W. Turner, R. Turner, L. Reid, University of North Carolina (publications submitted August 2007).

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