PuraMatrix® is the first commercial synthetic extracellular matrix (ECM) scaffold, enabling cells to be cultured in carefully controlled microenvironments for life science research, pharmaceutical drug discovery and bioproduction. PuraMatrix® enhances valuable and expensive cell assays that predict proper drug interactions and metabolism. In particular, PuraMatrix® has improved cell assays in which one or more types of cells form complex structures (such as spheroids, networks, synapses, vascularization). The result is improved models for in vivo and in vitro research and testing, increasing predictability and reducing the cost of drug discovery research. Click here to review PuraMatrix® Guidelines for Use.
Q. What cell types/applications are suitable for this material?
A. PuraMatrix®, including the related family of amphipathic peptide gels, have been shown to promote, among others, the differentiation of primary rat hepatocytes and hepatocyte progenitor cells, murine endothelial and cardiomyocyte cells, rat pheochromocytoma cells (PC12), and hippocampal neurons. Studies have also demonstrated that PuraMatrix® supports the attachment of a variety of primary (e.g., neuronal, fibroblast, keratinocyte) and transformed (e.g., MG-63, SH-SY5Y, HEK293, NIH3T3) cell types. A partial list of other applications in which PuraMatrix® has been used includes:
Q. Does PuraMatrix® promote cell growth and differentiation in the absence of protein/growth factor supplementation?
A. PuraMatrix® can often complement typical culture media additives and substitute directly for other matrices, substrates and scaffolds. To achieve optimal cell growth and differentiation, it is necessary to determine the appropriate mixture of PuraMatrix® and bioactive molecules (e.g., growth factors, ECM proteins, and/or other molecules).
Q. Should cells be plated on top of the hydrogel (2D surface plating) or encapsulated within the material (3D encapsulation protocol)?
A. Either option is possible. The optimal plating configuration will depend on the cell type and the experimental objectives. Please refer to the Guidelines for Use for specific examples and recommendations.
Q. If cells are seeding onto the material using the surface plating method, will the cells migrate into the hydrogel?
A. Because the hydrogel ‘fibers’ are flexible (not covalently linked), certain cells will migrate into the hydrogel. 3-D cell structure formation (spheroids, endothelial tubes, neuronal networks, stromal co-cultures, etc.) will depend on the cell types and culture media composition. The capacity for migratory behavior will be dependent on the cell type used.
Q. What seeding density should be used?
A. 3-D Matrix suggests a seeding density comparable to that used for surface plating on standard tissue culture-treated or ECM-coated substrates. A seeding density of 0.5-1.0 x 106 cells/ml is recommended for 3-D encapsulation cultures.
Q. PuraMatrix® gels seem to be thick. How can I best seed cells, proteins and other additives into the gels with an even distribution?
A. PuraMatrix® thickens after sitting in the vial over a period of a few hours, but this gel can be liquefied (prior to the addition of salt or media) by sonication, vortexing, or even pipetting up and down.
Q. How long can cells survive on PuraMatrix®? What about scaffold degradation?
A. The actual duration of the culture will depend on the cell type, culture conditions, and concentration of PuraMatrix®. Different cultures in PuraMatrix® have remained viable for weeks and months.
Q. Can cells that have been maintained on PuraMatrix® be subcultured?
A. Yes. Cells can be recovered from the hydrogel and then sub-cultured for an additional period of growth/differentiation using a fresh layer of PuraMatrix® or an alternative growth substrate (e.g., TC-treated, ECM-coated). Please refer to theGuidelines for Use for the cell recovery protocol.
Q. What about co-culturing cells using PuraMatrix®?
A. Co-culturing of two different cell types can be achieved by first encapsulating the first cell type in PuraMatrix® and then overlaying the second cell type on the layer containing the first cell type. PuraMatrix® matrices can be used in a similar manner as collagen or Matrigel© ECM gels in sandwich cultures.
Q. How is PuraMatrix® similar to and/or different from agarose, collagen, hyaluronic acid, poly(ethylene glycol), and methylcellulose hydrogels for long-term cultures?
A. PuraMatrix® is similar to agarose, collagen and methylcellulose in that it will typically support the long-term growth of many different cell types, either for differentiation or tumorigenicity studies. Unlike collagen substrates and scaffolds, PuraMatrix® will not shrink due to contraction by fibroblasts and other cell types.
PuraMatrix® is different from the three listed matrices in that it is transparent, synthetic and supports anchorage dependent cell types. PuraMatrix® is often used at much lower concentrations (i.e. 1.0%, 0.5% and 0.25%) than other hydrogels, improving nutrient diffusion, cell morphology and cell viability. PuraMatrix® forms a loose gel, allowing improved culture, complex cell structure formation, analysis and recovery of cells. In many cases, differential cell growth will be evident and it is much easier to isolate cells, DNA and proteins from PuraMatrix® than other synthetic or animal-derived matrices.
Q. How are extracellular matrix proteins (Laminin, Collagen I, Collagen IV, Fibronectin, Integrin sequences, etc.) added into PuraMatrix® to create defined ECMs?
A. PuraMatrix® can be mixed with ECM proteins, growth factors, and other additives. Often, these additives are packaged in solutions containing salt, which activates formation of PuraMatrix® nanofibers. We recommend washing the additives with a sucrose solution to remove the salt, then mixing the additive(s) with PuraMatrix® before coating plates or inserts with the mixture.