Abstract: This granular material consists of a granular porous support bearing negative or positive charges, coated on its surface with a first layer of impregnation with a hydrophilic polymer bearing charges opposite to those of the support, the quantity of said charges present on said polymer being substantially equal to that of the charges present at the surface of the support; and another layer, bound to the first by irreversible chemical coupling, of another hydrophilic polymer which is functional, namely bearing groups endowing said functional hydrophilic polymer with a specific but reversible affinity for at least one biological substance. Among the applications of this material, there are mentioned the separation and purification of antithrombin III and coagulation factors (factors II, VII, VIII, IX, X), and separation of activated coagulation factors (activated factor II, activated factor IX, activated factor X) in solutions containing said non-activated factors.

Abstract: The present invention relates to the application, as the stationary phase in affinity chromatography for the purification of the FGF type growth factors, of the polymers or copolymers onto which --SO.sub.3 H and --SO.sub.3 M groups are randomly bound, groups in which M denotes a physiologically acceptable metal, as well as, preferably, --SO.sub.2 R groups, in which R denotes a radical obtained by removal of a hydrogen atom from the amino group of an amino acid or an amino acid derivative.The invention relates also to the obtaining of a purified bFGF or aFGF growth factor, or a mixture of these growth factors, consisting in carrying out an affinity chromatography on a resin such as defined hereinabove, by carrying out an elution with a neutral pH buffer having an ionic strength equivalent to that of a 0.15 M to 2.5 M NaCl solution.